Merge pull request 'chore(sonar): bulk-fix production INFO analyzer warnings + skill update' (#12) from chore/sonarqube-info-prod-bulk into main

Reviewed-on: #12

.claude/skills/sonarqube/SKILL.MD

@@ -38,29 +38,74 @@ Invoke-RestMethod -Uri "$url/api/issues/search?componentKeys=sql-utilities&resol
 
 `SONARQUBE_URL` / `SONARQUBE_TOKEN` are read here; `scan-sonar.ps1` reads the separate `SONAR_TOKEN` / `SONAR_HOST_URL` for the *upload* path — do not conflate them.
 
-## B — Cleanup loop
+## B — Cleanup loop (tiered)
 
 ```dot
 digraph cleanup {
-    query [label="Query open issues + facets"];
+    query [label="Query open issues + facets=rules"];
-    pick [label="Pick one rule group"];
+    triage [label="Tier each rule:\nmechanical / judgment / API-impact"];
-    edit [label="Edit code"];
+    t1 [label="Tier 1 — mechanical:\nbulk-fix in one commit"];
-    build [label="dotnet build -c Release"];
+    t2 [label="Tier 2 — judgment:\none commit per rule, audit diff"];
-    test  [label="dotnet test -c Release --no-build"];
+    t3 [label="Tier 3 — API-impact:\nmanual, accept !breaking or skip"];
-    commit [label="git commit\nchore(sonar): … (Sxxxx)"];
+    build [label="dotnet build + dotnet test\nafter EACH commit"];
-    more [label="More groups?" shape=diamond];
+    push [label="git push + open PR"];
-    scan [label="scan-sonar.ps1"];
+    ci [label="CI runs SonarScanner\non Java 17"];
-    verify [label="Query API: confirm net-down"];
+    verify [label="Re-query API:\nconfirm rule counts dropped"];
 
-    query -> pick -> edit -> build -> test -> commit -> more;
+    query -> triage;
-    more -> pick [label="yes"];
+    triage -> t1 -> build;
-    more -> scan [label="no"];
+    triage -> t2 -> build;
-    scan -> verify;
+    triage -> t3 -> build;
+    build -> push -> ci -> verify;
 }
 ```
 
-1. **Query.** Start with `severities=MAJOR,MINOR` + `facets=rules` to see what's worth fixing.
+**The loop has shifted from per-rule commits to *tiered batches* once a project has more than a handful of issues left.** Use `dotnet format analyzers --diagnostics <ids> --severity info` — it runs all the Roslyn-shipped code fixers for the listed diagnostics, including `CA*`, `IDE*`, and `NUnit*`. (The `csharpsquid:Sxxxx` family from SonarAnalyzer.CSharp usually has no `dotnet format` fixer; those still need manual edits.)
-2. **Pick a rule group.** One Sxxxx (or one tightly-related cluster) per commit, easiest first so a late blocker doesn't strand the others.
+
-3. **Edit → build → test.** Build must succeed; the warning count for the touched rule must drop. Tests must stay green. If a fix would degrade clarity or break a tested contract, prefer **Won't Fix on the server with a justification** over a forced code change — see [[sonarqube-wontfix-rules]] for the catalog of rules already triaged that way (S1168, S3925, CS8601, S107).
+### Tier 1 — mechanical (one bulk commit)
-4. **Commit.** `chore(sonar): <one-line> (Sxxxx)` — bang (`!`) if it's a breaking rename.
+
-5. **After all groups:** `./scan-sonar.ps1` (needs `$env:SONAR_TOKEN`). Wait ~30-60s for the CE task to finish, then re-query the issues endpoint and confirm the open MAJOR/MINOR count fell by the expected number.
+Rules where the fixer's rewrite is purely syntactic and can't change behavior — pile them into one `dotnet format` invocation, audit the diff for sanity, build, test, single commit:
+
+```powershell
+dotnet format analyzers Strata.SqlTools.QueryBreakdown.sln `
+  --diagnostics IDE0028 CA1825 CA1834 CA1845 CA1847 CA1860 CA1866 CA1853 CA1830 CA2249 `
+  --severity info --verbosity normal
+```
+
+Typical safe rules: `IDE0028`, `CA1825`, `CA1834`, `CA1845`, `CA1847`, `CA1853`, `CA1860`, `CA1866`, `CA2249`, `CA1830`. Some rules in this family report "no associated code fix" — they'll need manual handling separately.
+
+### Tier 2 — judgment (one commit per rule)
+
+Rules whose fixer can produce mediocre output or surprise the reader — bulk-fix but **audit before staging**:
+
+- `CA1510` — `ArgumentNullException.ThrowIfNull` rollup; always safe but voluminous, deserves its own commit.
+- `CA1822` — make-method-static; the fixer also rewrites internal callers to use type-name form. **Public methods becoming static are a binary-break for external NuGet consumers** — commit with `chore(sonar)!:` and a `BREAKING CHANGE:` footer naming each affected member, or revert those file diffs and apply only the private-helper changes.
+- `CA1861` — hoists constant array args to `static readonly` fields. The fixer's field names are sometimes cryptic (`stringArray`, `arg2`) or it emits duplicate `separator` fields in the same class. After running, rename ugly fields and dedupe collisions before committing.
+- `CA1854` — `TryGetValue`-style double-lookup elimination; trivial.
+- `CA1859` — concrete return type for perf. **No batch fixer**: edit each site manually after checking visibility. Apply only to private/internal/test; on public/protected, either revert or treat as a `!breaking` change (most cases are private helpers, so this is usually fine).
+
+### Tier 3 — manual (no fixer)
+
+`CA1806`, `CA1846`, `CA1869`, the `csharpsquid:Sxxxx` family that has no `dotnet format` fixer, and individual public-API rules that need design judgment. Edit by hand, one rule at a time. If a fix would degrade clarity or break a tested contract, prefer **server-side Won't Fix with justification** — see [[sonarqube-wontfix-rules]] for the catalog already triaged that way (S1168, S3925, CS8601, S107).
+
+### Guardrail
+
+After every commit (Tier 1, 2, or 3):
+
+```powershell
+dotnet build Strata.SqlTools.QueryBreakdown.sln -c Release --nologo
+dotnet test  Strata.SqlTools.QueryBreakdown.sln -c Release --no-build --nologo
+```
+
+Build succeeds with no new warnings beyond the baseline. Tests stay green. If either fails, fix or revert before continuing to the next tier — incremental builds can mask warning regressions, so re-run with `--no-incremental` if the warning count looks suspicious.
+
+### Scan & verify
+
+**Local `./scan-sonar.ps1` is blocked here** — the system JRE is 8 and the SonarScanner CLI requires Java 17 (`UnsupportedClassVersionError`). CI handles the scan: `.gitea/workflows/sonarqube.yml` runs `actions/setup-java@v4` with `temurin` 17 and uploads on every push and PR. So the path is **push → open PR → CI scans → re-query the API to confirm net-down**:
+
+```powershell
+$h = @{ Authorization = "Basic $b64" }
+Invoke-RestMethod -Uri "$url/api/issues/search?componentKeys=sql-utilities&resolved=false&facets=rules&ps=500" -Headers $h
+```
+
+The targeted rule IDs should each drop to 0 (or near-0 if the fixer left a few cases it couldn't batch-resolve). Commit subject style stays `chore(sonar): … (RuleId)` — bang (`!`) if the change is a deliberate breaking rename or visibility shift.

src/Strata.SqlTools.LinqToSql/Analyzers/QueryCollectionAnalyzer.cs

@@ -186,9 +186,9 @@ public class QueryCollectionAnalyzer
             var table = query.FromClause?.Clause?.Trim();
             if (!string.IsNullOrWhiteSpace(table))
             {
-                if (tableUsage.ContainsKey(table))
+                if (tableUsage.TryGetValue(table, out int value))
                 {
-                    tableUsage[table]++;
+                    tableUsage[table] = ++value;
                 }
                 else
                 {
@@ -221,9 +221,9 @@ public class QueryCollectionAnalyzer
             foreach (var col in columns)
             {
                 var columnName = col.Trim();
-                if (columnUsage.ContainsKey(columnName))
+                if (columnUsage.TryGetValue(columnName, out int value))
                 {
-                    columnUsage[columnName]++;
+                    columnUsage[columnName] = ++value;
                 }
                 else
                 {

src/Strata.SqlTools.LinqToSql/Breakdowns/LinqQueryBreakdown.cs

@@ -71,10 +71,7 @@ public class LinqQueryBreakdown : QueryBreakdown
     /// <returns>A LinqQueryBreakdown representing the query structure.</returns>
     public static LinqQueryBreakdown Analyze<T>(IQueryable<T> query)
     {
-        if (query == null)
+        ArgumentNullException.ThrowIfNull(query);
-        {
-            throw new ArgumentNullException(nameof(query));
-        }
 
         var breakdown = new LinqQueryBreakdown
         {
@@ -232,10 +229,7 @@ public class LinqQueryBreakdown : QueryBreakdown
     /// <returns>An InsertBreakdown representing the insert operation.</returns>
     public static Breakdowns.SqlServer.InsertBreakdown AnalyzeInsert<T>(T entity) where T : class
     {
-        if (entity == null)
+        ArgumentNullException.ThrowIfNull(entity);
-        {
-            throw new ArgumentNullException(nameof(entity));
-        }
 
         var breakdown = new Breakdowns.SqlServer.InsertBreakdown();
         breakdown.TableName.Clause = typeof(T).Name;
@@ -312,10 +306,7 @@ public class LinqQueryBreakdown : QueryBreakdown
     /// <returns>A DeleteBreakdown representing the delete operation.</returns>
     public static Breakdowns.SqlServer.DeleteBreakdown AnalyzeDelete<T>(Expression<Func<T, bool>> filterExpression) where T : class
     {
-        if (filterExpression == null)
+        ArgumentNullException.ThrowIfNull(filterExpression);
-        {
-            throw new ArgumentNullException(nameof(filterExpression));
-        }
 
         var breakdown = new Breakdowns.SqlServer.DeleteBreakdown();
         breakdown.FromClause.Clause = typeof(T).Name;
@@ -343,14 +334,8 @@ public class LinqQueryBreakdown : QueryBreakdown
         Expression<Func<T, bool>> filterExpression,
         Expression<Func<T, T>> updateExpression) where T : class
     {
-        if (filterExpression == null)
+        ArgumentNullException.ThrowIfNull(filterExpression);
-        {
+        ArgumentNullException.ThrowIfNull(updateExpression);
-            throw new ArgumentNullException(nameof(filterExpression));
-        }
-        if (updateExpression == null)
-        {
-            throw new ArgumentNullException(nameof(updateExpression));
-        }
 
         var breakdown = new Breakdowns.SqlServer.UpdateBreakdown();
         breakdown.TableName.Clause = typeof(T).Name;
@@ -425,10 +410,7 @@ public class LinqQueryBreakdown : QueryBreakdown
     /// <returns>A string representation of the trace analysis.</returns>
     public static string AnalyzeTrace<T>(IQueryable<T> query, string? executionContext = null) where T : class
     {
-        if (query == null)
+        ArgumentNullException.ThrowIfNull(query);
-        {
-            throw new ArgumentNullException(nameof(query));
-        }
 
         var lines = new List<string>
         {
@@ -580,7 +562,7 @@ public class LinqQueryBreakdown : QueryBreakdown
     /// <returns>True if SELECT contains *; otherwise, false.</returns>
     public bool SelectsAllColumns()
     {
-        return SelectClause?.Clause?.Contains("*") ?? false;
+        return SelectClause?.Clause?.Contains('*') ?? false;
     }
 
     /// <summary>

src/Strata.SqlTools.LinqToSql/Converters/ReverseConverterExtensions.cs

@@ -18,10 +18,7 @@ public static class ReverseConverterExtensions
     /// <returns>A new LinqQueryBreakdown with the same clauses.</returns>
     public static LinqQueryBreakdown ToLinqQueryBreakdown(this QueryBreakdown breakdown)
     {
-        if (breakdown == null)
+        ArgumentNullException.ThrowIfNull(breakdown);
-        {
-            throw new ArgumentNullException(nameof(breakdown));
-        }
 
         var linq = new LinqQueryBreakdown(
             breakdown.SelectClause?.Clause ?? "*",
@@ -54,10 +51,7 @@ public static class ReverseConverterExtensions
     /// <returns>A new LinqQueryBreakdown with the same clauses.</returns>
     public static LinqQueryBreakdown ToLinqQueryBreakdown(this PostgreSqlBreakdown breakdown)
     {
-        if (breakdown == null)
+        ArgumentNullException.ThrowIfNull(breakdown);
-        {
-            throw new ArgumentNullException(nameof(breakdown));
-        }
 
         var linq = new LinqQueryBreakdown(
             breakdown.SelectClause?.Clause ?? "*",
@@ -90,10 +84,7 @@ public static class ReverseConverterExtensions
     /// <returns>A new LinqQueryBreakdown with the same clauses.</returns>
     public static LinqQueryBreakdown ToLinqQueryBreakdown(this SnowflakeBreakdown breakdown)
     {
-        if (breakdown == null)
+        ArgumentNullException.ThrowIfNull(breakdown);
-        {
-            throw new ArgumentNullException(nameof(breakdown));
-        }
 
         var linq = new LinqQueryBreakdown(
             breakdown.SelectClause?.Clause ?? "*",
@@ -127,10 +118,7 @@ public static class ReverseConverterExtensions
     /// <returns>A new breakdown in the target dialect format.</returns>
     public static object ConvertToDialect(this QueryBreakdown breakdown, string targetDialect)
     {
-        if (breakdown == null)
+        ArgumentNullException.ThrowIfNull(breakdown);
-        {
-            throw new ArgumentNullException(nameof(breakdown));
-        }
 
         return targetDialect.ToLowerInvariant() switch
         {
@@ -150,10 +138,7 @@ public static class ReverseConverterExtensions
     /// <returns>A new breakdown in the target dialect format.</returns>
     public static object ConvertToDialect(this PostgreSqlBreakdown breakdown, string targetDialect)
     {
-        if (breakdown == null)
+        ArgumentNullException.ThrowIfNull(breakdown);
-        {
-            throw new ArgumentNullException(nameof(breakdown));
-        }
 
         return targetDialect.ToLowerInvariant() switch
         {
@@ -173,10 +158,7 @@ public static class ReverseConverterExtensions
     /// <returns>A new breakdown in the target dialect format.</returns>
     public static object ConvertToDialect(this SnowflakeBreakdown breakdown, string targetDialect)
     {
-        if (breakdown == null)
+        ArgumentNullException.ThrowIfNull(breakdown);
-        {
-            throw new ArgumentNullException(nameof(breakdown));
-        }
 
         return targetDialect.ToLowerInvariant() switch
         {

src/Strata.SqlTools.LinqToSql/Validators/QueryValidator.cs

@@ -71,10 +71,7 @@ public class QueryValidator
     /// <returns>This validator for method chaining.</returns>
     public QueryValidator Validate(LinqQueryBreakdown breakdown)
     {
-        if (breakdown == null)
+        ArgumentNullException.ThrowIfNull(breakdown);
-        {
-            throw new ArgumentNullException(nameof(breakdown));
-        }
 
         _issues.Clear();
 
@@ -225,7 +222,7 @@ public class QueryValidator
         }
     }
 
-    private void ValidateWhereClause(LinqQueryBreakdown breakdown)
+    private static void ValidateWhereClause(LinqQueryBreakdown breakdown)
     {
         // No validation needed - WHERE is optional
     }
@@ -245,12 +242,12 @@ public class QueryValidator
         }
     }
 
-    private void ValidateHavingClause(LinqQueryBreakdown breakdown)
+    private static void ValidateHavingClause(LinqQueryBreakdown breakdown)
     {
         // Validation delegated to ValidateGroupByClause
     }
 
-    private void ValidateOrderByClause(LinqQueryBreakdown breakdown)
+    private static void ValidateOrderByClause(LinqQueryBreakdown breakdown)
     {
         // No validation needed - ORDER BY is optional
     }

src/Strata.SqlTools.LinqToSql/Visitors/LinqExpressionVisitor.cs

@@ -248,13 +248,13 @@ public class LinqExpressionVisitor : ExpressionVisitor
     {
         if (_isInWhereClause)
         {
-            _whereBuilder.Append("(");
+            _whereBuilder.Append('(');
             Visit(node.Left);
 
             _whereBuilder.Append($" {GetOperator(node.NodeType)} ");
 
             Visit(node.Right);
-            _whereBuilder.Append(")");
+            _whereBuilder.Append(')');
 
             return node;
         }
@@ -323,7 +323,7 @@ public class LinqExpressionVisitor : ExpressionVisitor
         return expression.ToString();
     }
 
-    private string GetFullMemberName(MemberExpression expression)
+    private static string GetFullMemberName(MemberExpression expression)
     {
         var parts = new Stack<string>();
         var current = expression;
@@ -354,7 +354,7 @@ public class LinqExpressionVisitor : ExpressionVisitor
         return string.Join(".", parts);
     }
 
-    private string GetOperator(ExpressionType nodeType)
+    private static string GetOperator(ExpressionType nodeType)
     {
         return nodeType switch
         {

src/Strata.SqlTools.Markdown/Expressions/ExpressionGenerator.cs

@@ -260,7 +260,7 @@ public class ExpressionGenerator : IVisitor<string>
         return sb.ToString();
     }
 
-    private int GenerateMermaidNodes(Expression expression, StringBuilder sb, Dictionary<object, int> nodeMap, ref int nodeCounter)
+    private static int GenerateMermaidNodes(Expression expression, StringBuilder sb, Dictionary<object, int> nodeMap, ref int nodeCounter)
     {
         var currentNode = nodeCounter++;
         nodeMap[expression] = currentNode;
@@ -366,7 +366,7 @@ public class ExpressionGenerator : IVisitor<string>
         {
             return text;
         }
-        return text.Substring(0, maxLength) + "...";
+        return string.Concat(text.AsSpan(0, maxLength), "...");
     }
 
     #region IVisitor Implementation
@@ -583,7 +583,7 @@ public class ExpressionGenerator : IVisitor<string>
     {
         var sb = new StringBuilder();
         sb.AppendLine($"{Indent()}Function: {function.FunctionName}");
-        if (function.Arguments.Any())
+        if (function.Arguments.Length != 0)
         {
             _indentLevel++;
             sb.AppendLine($"{Indent()}Arguments:");
@@ -602,7 +602,7 @@ public class ExpressionGenerator : IVisitor<string>
     {
         var sb = new StringBuilder();
         sb.AppendLine($"{Indent()}Aggregate Function: {aggregateFunction.FunctionName}");
-        if (aggregateFunction.Arguments.Any())
+        if (aggregateFunction.Arguments.Length != 0)
         {
             _indentLevel++;
             sb.AppendLine($"{Indent()}Arguments:");

src/Strata.SqlTools.Markdown/Expressions/SimpleExpressionGenerator.cs

@@ -106,7 +106,7 @@ public class SimpleExpressionGenerator
         return sb.ToString();
     }
 
-    private string GetExpressionDescription(Expression expression)
+    private static string GetExpressionDescription(Expression expression)
     {
         var typeName = expression.GetType().Name;
 

src/Strata.SqlTools.Markdown/LinqToSql/QueryBreakdownGenerator.cs

@@ -37,7 +37,7 @@ public class QueryBreakdownGenerator
     /// <param name="queryBreakdown">The LINQ QueryBreakdown to visualize.</param>
     /// <param name="title">Optional title for the diagram.</param>
     /// <returns>A string containing the Mermaid flowchart showing method calls.</returns>
-    public string GenerateMethodChainDiagram(LinqQueryBreakdown queryBreakdown, string? title = null)
+    public static string GenerateMethodChainDiagram(LinqQueryBreakdown queryBreakdown, string? title = null)
     {
         var sb = new System.Text.StringBuilder();
 

src/Strata.SqlTools.Markdown/LinqToSql/SqlStatementGenerator.cs

@@ -58,7 +58,7 @@ public class SqlStatementGenerator
     /// <param name="queryBreakdown">The query breakdown containing query information.</param>
     /// <param name="title">Optional title for the diagram.</param>
     /// <returns>A string containing the Mermaid diagram markdown.</returns>
-    public string GenerateLinqPipelineDiagram(IQueryBreakdown queryBreakdown, string? title = null)
+    public static string GenerateLinqPipelineDiagram(IQueryBreakdown queryBreakdown, string? title = null)
     {
         var sb = new System.Text.StringBuilder();
 

src/Strata.SqlTools.Markdown/SqlServer/QueryBreakdownGenerator.cs

@@ -177,7 +177,7 @@ public class QueryBreakdownGenerator
     /// <summary>
     /// Escapes text for Mermaid diagram labels to prevent syntax errors.
     /// </summary>
-    private string EscapeMermaidText(string text)
+    private static string EscapeMermaidText(string text)
     {
         return text
             .Replace("\"", "&quot;")
@@ -194,14 +194,14 @@ public class QueryBreakdownGenerator
     /// <summary>
     /// Truncates text to a maximum length and adds ellipsis if needed.
     /// </summary>
-    private string TruncateText(string text, int maxLength)
+    private static string TruncateText(string text, int maxLength)
     {
         if (string.IsNullOrWhiteSpace(text) || text.Length <= maxLength)
         {
             return text;
         }
 
-        return text.Substring(0, maxLength) + "...";
+        return string.Concat(text.AsSpan(0, maxLength), "...");
     }
 }
 

src/Strata.SqlTools.Markdown/SqlServer/SqlStatementGenerator.cs

@@ -104,7 +104,7 @@ public class SqlStatementGenerator
     /// <summary>
     /// Escapes text for Mermaid diagram labels.
     /// </summary>
-    private string EscapeMermaidText(string text)
+    private static string EscapeMermaidText(string text)
     {
         return text
             .Replace("\"", "&quot;")
@@ -115,20 +115,20 @@ public class SqlStatementGenerator
     /// <summary>
     /// Truncates text to a maximum length.
     /// </summary>
-    private string TruncateText(string text, int maxLength)
+    private static string TruncateText(string text, int maxLength)
     {
         if (string.IsNullOrWhiteSpace(text) || text.Length <= maxLength)
         {
             return text;
         }
 
-        return text.Substring(0, maxLength) + "...";
+        return string.Concat(text.AsSpan(0, maxLength), "...");
     }
 
     /// <summary>
     /// Cleans table name for use in Mermaid diagrams.
     /// </summary>
-    private string CleanTableName(string tableName)
+    private static string CleanTableName(string tableName)
     {
         return tableName
             .Replace("[", "")

src/Strata.SqlTools.PostgreSql/Statements/StatementExpressionParser.cs

@@ -129,7 +129,7 @@ public class StatementExpressionParser : SqlServerStatementExpressionParser
 
                 if (reader.TokenType == TokenType.String || reader.TokenType == TokenType.ColumnIdentifier)
                 {
-                    columnBuilder.Append(".").Append(reader.TokenValue);
+                    columnBuilder.Append('.').Append(reader.TokenValue);
                     reader.Read();
                 }
                 else
@@ -191,7 +191,7 @@ public class StatementExpressionParser : SqlServerStatementExpressionParser
 
             if (reader.TokenType == TokenType.ColumnIdentifier || reader.TokenType == TokenType.String)
             {
-                columnBuilder.Append(".").Append(reader.TokenValue);
+                columnBuilder.Append('.').Append(reader.TokenValue);
                 reader.Read();
             }
             else

src/Strata.SqlTools.PostgreSql/Statements/StatementParser.cs

@@ -113,9 +113,8 @@ public class StatementParser : SqlServerStatementParser
         // PostgreSQL-specific: Append LIMIT/OFFSET to ORDER BY if present
         var orderByClause = clauses.OrderByClause?.Clause ?? string.Empty;
 
-        if (clausePositions.ContainsKey(KeywordLimit))
+        if (clausePositions.TryGetValue(KeywordLimit, out int limitStart))
         {
-            var limitStart = clausePositions[KeywordLimit];
             var limitEnd = clausePositions.Values
                 .Where(v => v > limitStart)
                 .Order()
@@ -127,9 +126,8 @@ public class StatementParser : SqlServerStatementParser
                 : $"{orderByClause} {limitClause}";
         }
 
-        if (clausePositions.ContainsKey(KeywordOffset))
+        if (clausePositions.TryGetValue(KeywordOffset, out int offsetStart))
         {
-            var offsetStart = clausePositions[KeywordOffset];
             var offsetEnd = clausePositions.Values
                 .Where(v => v > offsetStart)
                 .Order()

src/Strata.SqlTools.Query/Value.cs

@@ -11,7 +11,7 @@ public class Value
 
     public IEnumerable<CalculationFilterGroup> FilterGroups { get; }
 
-    public Value() : this(string.Empty, string.Empty, new int[0], new string[0], new CalculationFilterGroup[0])
+    public Value() : this(string.Empty, string.Empty, Array.Empty<int>(), Array.Empty<string>(), Array.Empty<CalculationFilterGroup>())
     {
     }
 

src/Strata.SqlTools.Rules/Rule/Expression/Markdown.cs

@@ -115,7 +115,7 @@ public static class Markdown
         return ParseAtomicExpression(text);
     }
 
-    private static Expression? TryParseLogicalOperation(string text)
+    private static BoolExpr? TryParseLogicalOperation(string text)
     {
         foreach (var op in LogicalOperators.Keys)
         {
@@ -130,7 +130,7 @@ public static class Markdown
         return null;
     }
 
-    private static Expression? TryParseComparison(string text)
+    private static Comparison? TryParseComparison(string text)
     {
         foreach (var op in ComparisonOperators.Keys)
         {

src/Strata.SqlTools.Rules/Rule/RuleSet.cs

@@ -50,7 +50,7 @@ public class RuleSet : IGroup
     /// </summary>
     /// <param name="group">The rule group to traverse.</param>
     /// <returns>An enumerable of all single rules found in the group.</returns>
-    private static IEnumerable<SingleRule> GetAllSingleRules(IGroup group)
+    private static List<SingleRule> GetAllSingleRules(IGroup group)
     {
         var rules = new List<SingleRule>();
         foreach (var rule in group.Rules)

src/Strata.SqlTools.Snowflake/Breakdowns/ProcedureBreakdown.cs

@@ -55,7 +55,7 @@ public class ProcedureBreakdown : SqlServerProcedureBreakdown
 
         sb.Append("CALL ");
         sb.Append(ProcedureName.Clause);
-        sb.Append("(");
+        sb.Append('(');
 
         if (IsUsingParameters)
         {
@@ -68,7 +68,7 @@ public class ProcedureBreakdown : SqlServerProcedureBreakdown
             sb.Append(string.Join(", ", paramList));
         }
 
-        sb.Append(")");
+        sb.Append(')');
 
         return sb.ToString();
     }

src/Strata.SqlTools.Snowflake/Breakdowns/QueryBreakdown.cs

@@ -141,7 +141,7 @@ public class QueryBreakdown : SqlServerQueryBreakdown
 
         if (parameterName.StartsWith('@'))
         {
-            return ":" + parameterName.Substring(1);
+            return string.Concat(":", parameterName.AsSpan(1));
         }
 
         // Add : prefix
@@ -159,7 +159,7 @@ public class QueryBreakdown : SqlServerQueryBreakdown
             if (paramName.StartsWith(':'))
             {
                 // Add @param version
-                var atParam = "@" + paramName.Substring(1);
+                var atParam = string.Concat("@", paramName.AsSpan(1));
                 if (!Parameters.ContainsKey(atParam))
                 {
                     Parameters[atParam] = Parameters[paramName];
@@ -168,7 +168,7 @@ public class QueryBreakdown : SqlServerQueryBreakdown
             else if (paramName.StartsWith('@'))
             {
                 // Add :param version
-                var colonParam = ":" + paramName.Substring(1);
+                var colonParam = string.Concat(":", paramName.AsSpan(1));
                 if (!Parameters.ContainsKey(colonParam))
                 {
                     Parameters[colonParam] = Parameters[paramName];
@@ -539,7 +539,7 @@ public class QueryBreakdown : SqlServerQueryBreakdown
 
                 if (i > 0)
                 {
-                    sb.Append(",");
+                    sb.Append(',');
                     sb.AppendLine();
                 }
 

src/Strata.SqlTools.Snowflake/Breakdowns/QueryBreakdownCollection.cs

@@ -67,7 +67,7 @@ public class QueryBreakdownCollection : SqlServer.QueryBreakdownCollectionBase<Q
 
                 if (!trimmed.EndsWith(';'))
                 {
-                    sb.Append(";");
+                    sb.Append(';');
                 }
 
                 // Add spacing between statements
@@ -111,7 +111,7 @@ public class QueryBreakdownCollection : SqlServer.QueryBreakdownCollectionBase<Q
                 return true;
             }
 
-            var specificPattern = stageName.Contains("~")
+            var specificPattern = stageName.Contains('~')
                 ? $@"@~/{System.Text.RegularExpressions.Regex.Escape(stageName.TrimStart('@', '~', '/'))}/"
                 : $@"@{System.Text.RegularExpressions.Regex.Escape(stageName.TrimStart('@'))}/";
 
@@ -182,6 +182,15 @@ public class QueryBreakdownCollection : SqlServer.QueryBreakdownCollectionBase<Q
         });
     }
 
+    private static readonly string[] SnowflakeFunctionNames =
+    [
+        "PARSE_JSON", "OBJECT_INSERT", "ARRAY_CONSTRUCT", "ARRAY_AGG",
+        "FLATTEN", "GET_PATH", "TRY_PARSE_JSON", "JSON_EXTRACT_PATH_TEXT",
+        "JSON_EXTRACT_PATH_WITH_DEFAULT", "HASHAGGREGATE", "LISTAGG",
+        "APPROX_COUNT_DISTINCT", "APPROX_PERCENTILE", "GREATEST", "LEAST",
+        "NULLIF", "ZEROIFNULL", "STRTOK", "SPLIT_PART", "PIVOT", "UNPIVOT"
+    ];
+
     /// <summary>
     /// Filters queries that use Snowflake functions (PARSE_JSON, OBJECT_INSERT, ARRAY, etc.).
     /// </summary>
@@ -191,17 +200,7 @@ public class QueryBreakdownCollection : SqlServer.QueryBreakdownCollectionBase<Q
         return QueryBreakdownList.Where(q =>
         {
             var sql = q.GetSql().ToUpperInvariant();
-
+            return SnowflakeFunctionNames.Any(func => sql.Contains(func));
-            var snowflakeFunctions = new[]
-            {
-                "PARSE_JSON", "OBJECT_INSERT", "ARRAY_CONSTRUCT", "ARRAY_AGG",
-                "FLATTEN", "GET_PATH", "TRY_PARSE_JSON", "JSON_EXTRACT_PATH_TEXT",
-                "JSON_EXTRACT_PATH_WITH_DEFAULT", "HASHAGGREGATE", "LISTAGG",
-                "APPROX_COUNT_DISTINCT", "APPROX_PERCENTILE", "GREATEST", "LEAST",
-                "NULLIF", "ZEROIFNULL", "STRTOK", "SPLIT_PART", "PIVOT", "UNPIVOT"
-            };
-
-            return snowflakeFunctions.Any(func => sql.Contains(func));
         });
     }
 
@@ -289,7 +288,7 @@ public class QueryBreakdownCollection : SqlServer.QueryBreakdownCollectionBase<Q
     /// </summary>
     private static bool UsesStageReference(QueryBreakdown query)
     {
-        return query.GetSql().Contains("@") &&
+        return query.GetSql().Contains('@') &&
                (query.GetSql().Contains("FROM @") || query.GetSql().Contains(" @"));
     }
 

src/Strata.SqlTools.Snowflake/Statements/StatementParser.cs

@@ -119,9 +119,9 @@ public class StatementParser : SqlServerStatementParser
     protected override void PostProcessClauses(SqlClauses clauses, string sql, Dictionary<string, int> clausePositions)
     {
         // Snowflake-specific: Append LIMIT to ORDER BY if present
-        if (clausePositions.ContainsKey(KeywordLimit))
+        if (clausePositions.TryGetValue(KeywordLimit, out int value))
         {
-            var limitClause = sql.Substring(clausePositions[KeywordLimit]).Trim();
+            var limitClause = sql.Substring(value).Trim();
             if (clauses.OrderByClause != null)
             {
                 clauses.OrderByClause.Clause = string.IsNullOrEmpty(clauses.OrderByClause.Clause)

src/Strata.SqlTools.SqlBreakdown/Classes/SqlBreakdownCollection.cs

@@ -88,10 +88,7 @@ public class SqlBreakdownCollection : ICollection<ISqlBreakdown>
     /// <exception cref="ArgumentNullException">Thrown when breakdown is null.</exception>
     public void Add(ISqlBreakdown breakdown)
     {
-        if (breakdown == null)
+        ArgumentNullException.ThrowIfNull(breakdown);
-        {
-            throw new ArgumentNullException(nameof(breakdown));
-        }
 
         _breakdowns.Add(breakdown);
     }
@@ -103,10 +100,7 @@ public class SqlBreakdownCollection : ICollection<ISqlBreakdown>
     /// <exception cref="ArgumentNullException">Thrown when breakdowns is null.</exception>
     public void AddRange(IEnumerable<ISqlBreakdown> breakdowns)
     {
-        if (breakdowns == null)
+        ArgumentNullException.ThrowIfNull(breakdowns);
-        {
-            throw new ArgumentNullException(nameof(breakdowns));
-        }
 
         _breakdowns.AddRange(breakdowns);
     }
@@ -142,10 +136,7 @@ public class SqlBreakdownCollection : ICollection<ISqlBreakdown>
     /// <exception cref="ArgumentNullException">Thrown when sqlBatch is null.</exception>
     public void ParseBatch(string sqlBatch, string? separator = null)
     {
-        if (sqlBatch == null)
+        ArgumentNullException.ThrowIfNull(sqlBatch);
-        {
-            throw new ArgumentNullException(nameof(sqlBatch));
-        }
 
         Clear();
 

src/Strata.SqlTools.SqlBreakdown/Classes/SqlExpressionClause.cs

@@ -85,7 +85,7 @@ public class SqlExpressionClause : SqlClause, ISqlExpressionClause
     /// </summary>
     /// <param name="clause">The clause to split.</param>
     /// <returns>An enumerable collection of individual items.</returns>
-    private static IEnumerable<string> SplitOnComma(string clause)
+    private static List<string> SplitOnComma(string clause)
     {
         var items = new List<string>();
         var current = new StringBuilder();

src/Strata.SqlTools.SqlBreakdown/Expressions/InputPropertyExpression.cs

@@ -269,20 +269,15 @@ public static class FlatDataUtils
 
     public static object GetValue(this IFlatData data, string key)
     {
-        if (data == null)
+        ArgumentNullException.ThrowIfNull(data);
-        {
-            throw new ArgumentNullException(nameof(data));
-        }
 
-        if (!data.ContainsKey(key))
+        if (!data.TryGetValue(key, out object? rawValue))
         {
             throw new ArgumentException(
                 $"The specified key is not available. Requested key: [{key}] Available keys: [{string.Join(", ", data.Keys)}]",
                 nameof(key));
         }
 
-        var rawValue = data[key];
-
         return rawValue;
     }
 

src/Strata.SqlTools.SqlBreakdown/Utilities/GuidUtils.cs

@@ -41,7 +41,7 @@ public static class GuidUtils
             return Guid.Empty;
         }
 
-        if (value.Contains("-"))
+        if (value.Contains('-'))
         {
             // This function was called on an already valid guid
             return new Guid(value);
@@ -92,7 +92,7 @@ public static class GuidUtils
         var sb = new System.Text.StringBuilder(newguid);
         while (sb.Length < Guid.Empty.ToString().Length)
         {
-            sb.Append(sb.ToString());
+            sb.Append(sb);
         }
         newguid = sb.ToString();
 
@@ -114,7 +114,7 @@ public static class GuidUtils
         for (int i = 0; i < guidChars.Length; i++)
         {
             char chr = guidChars[i];
-            if (valid.IndexOf(chr) == -1 && !((chr == '-') && (i == 8 || i == 13 || i == 18 || i == 23)))
+            if (!valid.Contains(chr) && !((chr == '-') && (i == 8 || i == 13 || i == 18 || i == 23)))
             {
                 guidChars[i] = valid[Math.Abs(StringUtils.GetHashCode32Bit(chr)) % valid.Length];
             }

src/Strata.SqlTools.SqlBreakdown/Utilities/SqlColumnHelpers.cs

@@ -16,7 +16,7 @@ public static partial class SqlUtils
     public static void AppendAliasColumnWithComma(StringBuilder stringBuilder, string alias, string columnName)
     {
         stringBuilder.Append(alias);
-        stringBuilder.Append(".");
+        stringBuilder.Append('.');
         stringBuilder.Append(columnName);
         stringBuilder.AppendLine(",");
     }
@@ -58,7 +58,7 @@ public static partial class SqlUtils
     {
         stringBuilder.Append("CAST(");
         stringBuilder.Append(alias);
-        stringBuilder.Append(".");
+        stringBuilder.Append('.');
         stringBuilder.Append(columnName);
         stringBuilder.Append(" AS ");
         stringBuilder.Append(dataType);
@@ -94,7 +94,7 @@ public static partial class SqlUtils
         {
             if (i > 0)
             {
-                sb.Append(",");
+                sb.Append(',');
             }
 
             string trimmed = columnNames[i].Trim();

src/Strata.SqlTools.SqlBreakdown/Utilities/SqlGuidHelpers.cs

@@ -42,10 +42,10 @@ public static partial class SqlUtils
 
         foreach (Guid g in guidList)
         {
-            sb.Append("'");
+            sb.Append('\'');
             sb.Append(g.ToString());
-            sb.Append("'");
+            sb.Append('\'');
-            sb.Append(",");
+            sb.Append(',');
         }
 
         return sb.ToString().Trim().TrimEnd(',');

src/Strata.SqlTools.SqlBreakdown/Utilities/SqlUtils.Filters.cs

@@ -27,7 +27,7 @@ public static partial class SqlUtils
         double.TryParse(value, out double dblValue);
 
         // Optimize IN if only one value
-        if (operation == FilterOperation.In && !value.Contains(","))
+        if (operation == FilterOperation.In && !value.Contains(','))
         {
             operation = FilterOperation.Equal;
         }
@@ -144,7 +144,7 @@ public static partial class SqlUtils
                 }
 
                 int lastCloseParen = sb.ToString().LastIndexOf(')');
-                filter.SqlExpression = sb.ToString().Substring(0, lastCloseParen + 1) + ")";
+                filter.SqlExpression = string.Concat(sb.ToString().AsSpan(0, lastCloseParen + 1), ")");
                 break;
 
             case FilterOperation.NotBetween:

src/Strata.SqlTools.SqlBreakdown/Utilities/SqlUtils.cs

@@ -23,6 +23,7 @@ public static partial class SqlUtils
     public const string DATETIME_INSERT_FORMAT = "yyyyMMdd HH:mm:ss";
 
     private const string DEFAULT_SCHEMA = "dbo";
+    private static readonly char[] separator = new[] { ',' };
 
     #region SQL String Manipulation
 
@@ -34,7 +35,7 @@ public static partial class SqlUtils
     public static string StripColumnTableAlias(string sql)
     {
         // Break sql into words and remove "abc." from each column
-        string[] commaWords = sql.Split(new[] { ',' }, StringSplitOptions.RemoveEmptyEntries);
+        string[] commaWords = sql.Split(separator, StringSplitOptions.RemoveEmptyEntries);
         var newParts = new List<string>();
 
         foreach (string commaWord in commaWords)

src/Strata.SqlTools.SqlServer/Breakdowns/QueryBreakdown.cs

@@ -578,7 +578,7 @@ public class QueryBreakdown : SqlBreakdownBase, IQueryBreakdown
 
                 if (i > 0)
                 {
-                    sb.Append(",");
+                    sb.Append(',');
                     sb.AppendLine();
                 }
 

src/Strata.SqlTools.SqlServer/Breakdowns/QueryBreakdownCollectionBase.cs

@@ -51,10 +51,7 @@ public abstract class QueryBreakdownCollectionBase<TQuery> : SqlBreakdownCollect
     /// <exception cref="ArgumentNullException">Thrown when <paramref name="queryBreakdown"/> is null.</exception>
     public void Add(TQuery queryBreakdown)
     {
-        if (queryBreakdown == null)
+        ArgumentNullException.ThrowIfNull(queryBreakdown);
-        {
-            throw new ArgumentNullException(nameof(queryBreakdown));
-        }
 
         QueryBreakdownList.Add(queryBreakdown);
         base.Add(queryBreakdown);
@@ -67,10 +64,7 @@ public abstract class QueryBreakdownCollectionBase<TQuery> : SqlBreakdownCollect
     /// <exception cref="ArgumentNullException">Thrown when <paramref name="queryBreakdowns"/> is null.</exception>
     public void AddRange(IEnumerable<TQuery> queryBreakdowns)
     {
-        if (queryBreakdowns == null)
+        ArgumentNullException.ThrowIfNull(queryBreakdowns);
-        {
-            throw new ArgumentNullException(nameof(queryBreakdowns));
-        }
 
         foreach (var breakdown in queryBreakdowns)
         {

src/Strata.SqlTools.SqlServer/Statements/StatementParser.cs

@@ -21,6 +21,7 @@ public class StatementParser
     public const string KeywordGroupBy = "GROUP BY";
     public const string KeywordHaving = "HAVING";
     public const string KeywordOrderBy = "ORDER BY";
+    private static readonly char[] separator = new[] { '\r', '\n' };
 
     #endregion
 
@@ -50,7 +51,7 @@ public class StatementParser
         // Replace multiple spaces/tabs with single space, but preserve newlines for comment handling
         sql = Regex.Replace(sql, @"[ \t]+", " ", RegexOptions.None, RegexDefaults.MatchTimeout);
         // Remove leading/trailing whitespace from each line
-        var lines = sql.Split(new[] { '\r', '\n' }, StringSplitOptions.None);
+        var lines = sql.Split(separator, StringSplitOptions.None);
         sql = string.Join("\n", lines.Select(line => line.Trim()));
         return sql.Trim();
     }

tests/Strata.SqlTools.EFCore.Tests/QueryBreakdownRepositoryTests.cs

@@ -11,7 +11,7 @@ public class QueryBreakdownRepositoryTests
 {
     private DbContext _dbContext = null!;
     private IQueryBreakdownMapper _mapper = null!;
-    private IQueryBreakdownRepository _repository = null!;
+    private QueryBreakdownRepository _repository = null!;
 
     [SetUp]
     public void Setup()

tests/Strata.SqlTools.LinqToSql.Tests/LinqQueryBreakdownTests.cs

@@ -7,6 +7,7 @@ namespace Strata.SqlTools.LinqToSql.Tests;
 public class LinqQueryBreakdownTests
 {
     private TestDataContext _context = null!;
+    private static readonly string[] separator = new[] { "AND" };
 
     [SetUp]
     public void Setup()
@@ -18,7 +19,7 @@ public class LinqQueryBreakdownTests
     public void Analyze_SimpleSelectQuery_ExtractsCorrectClauses()
     {
         // Arrange
-        var query = from user in _context.Users
+        var query = from user in TestDataContext.Users
                     select user;
 
         // Act
@@ -34,7 +35,7 @@ public class LinqQueryBreakdownTests
     public void Analyze_WhereClause_ExtractsCondition()
     {
         // Arrange
-        var query = from user in _context.Users
+        var query = from user in TestDataContext.Users
                     where user.Age > 21
                     select user;
 
@@ -51,7 +52,7 @@ public class LinqQueryBreakdownTests
     public void Analyze_SelectWithProjection_ExtractsSelectedFields()
     {
         // Arrange
-        var query = from user in _context.Users
+        var query = from user in TestDataContext.Users
                     select new { user.Id, user.Name };
 
         // Act
@@ -67,7 +68,7 @@ public class LinqQueryBreakdownTests
     public void Analyze_OrderByClause_ExtractsOrdering()
     {
         // Arrange
-        var query = from user in _context.Users
+        var query = from user in TestDataContext.Users
                     orderby user.Name
                     select user;
 
@@ -83,7 +84,7 @@ public class LinqQueryBreakdownTests
     public void Analyze_MethodSyntax_ExtractsCorrectClauses()
     {
         // Arrange
-        var query = _context.Users
+        var query = TestDataContext.Users
             .Where(u => u.Age > 18)
             .OrderBy(u => u.Name)
             .Select(u => new { u.Id, u.Name });
@@ -101,7 +102,7 @@ public class LinqQueryBreakdownTests
     public void Analyze_MethodSyntax_TracksMethodChain()
     {
         // Arrange
-        var query = _context.Users
+        var query = TestDataContext.Users
             .Where(u => u.Age > 18)
             .OrderBy(u => u.Name)
             .Select(u => u.Name);
@@ -120,7 +121,7 @@ public class LinqQueryBreakdownTests
     public void GetQuerySummary_ReturnsFormattedString()
     {
         // Arrange
-        var query = _context.Users.Where(u => u.Age > 21);
+        var query = TestDataContext.Users.Where(u => u.Age > 21);
         var breakdown = LinqQueryBreakdown.Analyze(query);
 
         // Act
@@ -137,7 +138,7 @@ public class LinqQueryBreakdownTests
     public void GetMethodChain_ReturnsMethodSequence()
     {
         // Arrange
-        var query = _context.Users.Where(u => u.Age > 18).OrderBy(u => u.Name);
+        var query = TestDataContext.Users.Where(u => u.Age > 18).OrderBy(u => u.Name);
         var breakdown = LinqQueryBreakdown.Analyze(query);
 
         // Act
@@ -153,7 +154,7 @@ public class LinqQueryBreakdownTests
     public void TryAnalyze_ValidQuery_ReturnsTrue()
     {
         // Arrange
-        var query = _context.Users.Where(u => u.Age > 21);
+        var query = TestDataContext.Users.Where(u => u.Age > 21);
 
         // Act
         var success = LinqQueryBreakdown.TryAnalyze(query, out var breakdown, out var error);
@@ -182,7 +183,7 @@ public class LinqQueryBreakdownTests
     public void Analyze_ComplexQuery_HandlesCombinedClauses()
     {
         // Arrange
-        var query = from user in _context.Users
+        var query = from user in TestDataContext.Users
                     where user.Age > 21 && user.IsActive
                     orderby user.Name descending
                     select new { user.Id, user.Name, user.Email };
@@ -205,7 +206,7 @@ public class LinqQueryBreakdownTests
     public void AnalyzeAndModify_AddWhereClause_GeneratesUpdatedSql()
     {
         // Arrange - Analyze an existing LINQ query
-        var originalQuery = _context.Users.Where(u => u.Age > 21);
+        var originalQuery = TestDataContext.Users.Where(u => u.Age > 21);
         var breakdown = LinqQueryBreakdown.Analyze(originalQuery);
 
         // Act - Add additional filter using breakdown
@@ -222,7 +223,7 @@ public class LinqQueryBreakdownTests
     public void AnalyzeAndModify_ChangeSelectClause_GeneratesNewProjection()
     {
         // Arrange - Analyze query with projection
-        var originalQuery = _context.Users.Select(u => new { u.Id, u.Name });
+        var originalQuery = TestDataContext.Users.Select(u => new { u.Id, u.Name });
         var breakdown = LinqQueryBreakdown.Analyze(originalQuery);
 
         // Act - Modify the SELECT clause
@@ -243,7 +244,7 @@ public class LinqQueryBreakdownTests
     public void AnalyzeAndModify_CloneAndExtend_CreatesIndependentQuery()
     {
         // Arrange - Analyze base query
-        var baseQuery = _context.Users.Where(u => u.Age > 18);
+        var baseQuery = TestDataContext.Users.Where(u => u.Age > 18);
         var baseBreakdown = LinqQueryBreakdown.Analyze(baseQuery);
 
         // Act - Clone and extend
@@ -267,10 +268,10 @@ public class LinqQueryBreakdownTests
     public void AnalyzeAndCompose_MultipleQueries_CreatesUnionScenario()
     {
         // Arrange - Analyze two different queries
-        var activeUsersQuery = _context.Users.Where(u => u.IsActive);
+        var activeUsersQuery = TestDataContext.Users.Where(u => u.IsActive);
         var activeBreakdown = LinqQueryBreakdown.Analyze(activeUsersQuery);
 
-        var recentUsersQuery = _context.Users.Where(u => u.Age < 25);
+        var recentUsersQuery = TestDataContext.Users.Where(u => u.Age < 25);
         var recentBreakdown = LinqQueryBreakdown.Analyze(recentUsersQuery);
 
         // Act - Get SQL for both (could be used in UNION scenario)
@@ -287,7 +288,7 @@ public class LinqQueryBreakdownTests
     public void AnalyzeAndBuildFilter_IncrementallyAddConditions_BuildsComplexFilter()
     {
         // Arrange - Start with simple query
-        var query = _context.Users;
+        var query = TestDataContext.Users;
         var breakdown = LinqQueryBreakdown.Analyze(query);
 
         // Act - Incrementally add filter conditions (simulating filter builder UI)
@@ -303,7 +304,7 @@ public class LinqQueryBreakdownTests
         Assert.That(filterSql, Does.Contain("IsActive = 1"));
 
         // Should have multiple AND conditions
-        var andCount = filterSql.Split(new[] { "AND" }, StringSplitOptions.None).Length - 1;
+        var andCount = filterSql.Split(separator, StringSplitOptions.None).Length - 1;
         Assert.That(andCount, Is.GreaterThanOrEqualTo(2));
     }
 
@@ -311,7 +312,7 @@ public class LinqQueryBreakdownTests
     public void AnalyzeAndPaginate_AddOrderAndLimits_CreatesPaginatedQuery()
     {
         // Arrange - Analyze base query
-        var query = _context.Users.Where(u => u.IsActive);
+        var query = TestDataContext.Users.Where(u => u.IsActive);
         var breakdown = LinqQueryBreakdown.Analyze(query);
 
         // Act - Add pagination (ORDER BY required for consistent pagination)
@@ -335,7 +336,7 @@ public class LinqQueryBreakdownTests
     public void AnalyzeAndGenerateReport_ExtractQueryMetrics_ProvidesAnalytics()
     {
         // Arrange - Complex query to analyze
-        var query = _context.Users
+        var query = TestDataContext.Users
             .Where(u => u.Age > 21)
             .Where(u => u.IsActive)
             .OrderBy(u => u.Name)
@@ -364,7 +365,7 @@ public class LinqQueryBreakdownTests
     public void AnalyzeAndOptimize_RemoveSelectStar_ImprovedProjection()
     {
         // Arrange - Analyze query with SELECT *
-        var query = _context.Users.Where(u => u.IsActive);
+        var query = TestDataContext.Users.Where(u => u.IsActive);
         var breakdown = LinqQueryBreakdown.Analyze(query);
 
         // Verify it initially has SELECT *
@@ -390,10 +391,10 @@ public class LinqQueryBreakdownTests
     public void AnalyzeMultipleQueries_CompareAndMerge_CreatesCompositeQuery()
     {
         // Arrange - Analyze two related queries
-        var usersQuery = _context.Users.Where(u => u.Age > 21);
+        var usersQuery = TestDataContext.Users.Where(u => u.Age > 21);
         var usersBreakdown = LinqQueryBreakdown.Analyze(usersQuery);
 
-        var activeQuery = _context.Users.Where(u => u.IsActive);
+        var activeQuery = TestDataContext.Users.Where(u => u.IsActive);
         var activeBreakdown = LinqQueryBreakdown.Analyze(activeQuery);
 
         // Act - Merge conditions from both queries
@@ -416,7 +417,7 @@ public class LinqQueryBreakdownTests
     public void AnalyzeAndDocument_GenerateQueryDocumentation_CreatesReadableOutput()
     {
         // Arrange - Analyze a business query
-        var query = _context.Orders
+        var query = TestDataContext.Orders
             .Where(o => o.Amount > 1000)
             .Where(o => o.OrderDate > DateTime.Now.AddDays(-30))
             .OrderBy(o => o.OrderDate);
@@ -451,8 +452,8 @@ public class LinqQueryBreakdownTests
 // Test data context and entities
 public class TestDataContext
 {
-    public IQueryable<User> Users => new List<User>().AsQueryable();
+    public static IQueryable<User> Users => new List<User>().AsQueryable();
-    public IQueryable<Order> Orders => new List<Order>().AsQueryable();
+    public static IQueryable<Order> Orders => new List<Order>().AsQueryable();
 }
 
 public class User
@@ -488,7 +489,7 @@ public class GetQueryTests
     public void GetQuery_LinqBreakdown_ReturnsNullByDefault()
     {
         // Arrange
-        var query = _context.Users.Where(u => u.Age > 18);
+        var query = TestDataContext.Users.Where(u => u.Age > 18);
         var breakdown = LinqQueryBreakdown.Analyze(query);
 
         // Act - GetQuery returns null because LinqQueryBreakdown needs the original provider
@@ -515,7 +516,7 @@ public class GetQueryTests
     public void GetQuery_MultipleBreakdownTypes_AllReturnNull()
     {
         // Arrange
-        var linqBreakdown = LinqQueryBreakdown.Analyze(_context.Users);
+        var linqBreakdown = LinqQueryBreakdown.Analyze(TestDataContext.Users);
         var sqlBreakdown = new QueryBreakdown("*", "Users");
 
         // Act
@@ -710,7 +711,7 @@ public class GetQueryTests
     public void AnalyzeTrace_WithValidQuery_ReturnsTraceString()
     {
         // Arrange
-        var query = _context.Users.Where(u => u.Age > 18);
+        var query = TestDataContext.Users.Where(u => u.Age > 18);
 
         // Act
         var trace = LinqQueryBreakdown.AnalyzeTrace(query);
@@ -726,7 +727,7 @@ public class GetQueryTests
     public void AnalyzeTrace_WithExecutionContext_IncludesContextInTrace()
     {
         // Arrange
-        var query = _context.Users;
+        var query = TestDataContext.Users;
         const string context = "Initial Load";
 
         // Act
@@ -754,7 +755,7 @@ public class GetQueryTests
     public void ConvertToSqlServerBreakdown_CopiesAllClauses()
     {
         // Arrange
-        var query = _context.Users.Where(u => u.Age > 21).OrderBy(u => u.Name);
+        var query = TestDataContext.Users.Where(u => u.Age > 21).OrderBy(u => u.Name);
         var breakdown = LinqQueryBreakdown.Analyze(query);
 
         // Act
@@ -772,7 +773,7 @@ public class GetQueryTests
     public void ConvertToPostgreSqlBreakdown_CopiesAllClauses()
     {
         // Arrange
-        var query = _context.Users
+        var query = TestDataContext.Users
             .Where(u => u.IsActive)
             .OrderBy(u => u.Name)
             .Select(u => new { u.Id, u.Name });
@@ -793,7 +794,7 @@ public class GetQueryTests
     public void ConvertToSnowflakeBreakdown_CopiesAllClauses()
     {
         // Arrange
-        var query = _context.Users.Where(u => u.Age > 21).OrderBy(u => u.Name);
+        var query = TestDataContext.Users.Where(u => u.Age > 21).OrderBy(u => u.Name);
         var breakdown = LinqQueryBreakdown.Analyze(query);
 
         // Act
@@ -827,7 +828,7 @@ public class GetQueryTests
     public void ConvertToPostgreSqlBreakdown_WithComplexQuery_CopieAllClauses()
     {
         // Arrange
-        var query = _context.Users
+        var query = TestDataContext.Users
             .Where(u => u.IsActive && u.Age >= 18)
             .OrderByDescending(u => u.Age);
 
@@ -848,7 +849,7 @@ public class GetQueryTests
     public void ConvertToSnowflakeBreakdown_PreservesAllClauseInformation()
     {
         // Arrange
-        var breakdown = LinqQueryBreakdown.Analyze(_context.Users.OrderBy(u => u.Name));
+        var breakdown = LinqQueryBreakdown.Analyze(TestDataContext.Users.OrderBy(u => u.Name));
 
         // Act
         var snowflakeBreakdown = breakdown.ConvertToSnowflakeBreakdown();
@@ -862,7 +863,7 @@ public class GetQueryTests
     public void ConvertToSqlServerBreakdown_InstancesAreIndependent()
     {
         // Arrange
-        var breakdown = LinqQueryBreakdown.Analyze(_context.Users.Where(u => u.Age > 21));
+        var breakdown = LinqQueryBreakdown.Analyze(TestDataContext.Users.Where(u => u.Age > 21));
         var sqlServerBreakdown = breakdown.ConvertToSqlServerBreakdown();
 
         // Act - Modify the SQL Server breakdown
@@ -876,7 +877,7 @@ public class GetQueryTests
     public void ConvertChainMultipleTimes_EachConversionIndependent()
     {
         // Arrange
-        var breakdown = LinqQueryBreakdown.Analyze(_context.Users.OrderBy(u => u.Name));
+        var breakdown = LinqQueryBreakdown.Analyze(TestDataContext.Users.OrderBy(u => u.Name));
 
         // Act
         var sqlServer1 = breakdown.ConvertToSqlServerBreakdown();

tests/Strata.SqlTools.Markdown.Tests/LinqToSql/QueryBreakdownGeneratorTests.cs

@@ -20,7 +20,7 @@ public class QueryBreakdownGeneratorTests
     public void GenerateMermaidDiagram_SimpleLinqQuery_GeneratesValidMermaid()
     {
         // Arrange
-        var query = _context.Users.Where(u => u.Age > 21);
+        var query = TestDataContext.Users.Where(u => u.Age > 21);
         var breakdown = LinqQueryBreakdown.Analyze(query);
 
         // Act
@@ -39,14 +39,14 @@ public class QueryBreakdownGeneratorTests
     public void GenerateMethodChainDiagram_WithMethodCalls_ShowsChain()
     {
         // Arrange
-        var query = _context.Users
+        var query = TestDataContext.Users
             .Where(u => u.Age > 18)
             .OrderBy(u => u.Name)
             .Select(u => new { u.Id, u.Name });
         var breakdown = LinqQueryBreakdown.Analyze(query);
 
         // Act
-        var result = _generator.GenerateMethodChainDiagram(breakdown, "Method Chain");
+        var result = QueryBreakdownGenerator.GenerateMethodChainDiagram(breakdown, "Method Chain");
 
         // Assert
         Assert.That(result, Does.Contain("```mermaid"));
@@ -66,7 +66,7 @@ public class QueryBreakdownGeneratorTests
         var breakdown = new LinqQueryBreakdown("*", "Users");
 
         // Act
-        var result = _generator.GenerateMethodChainDiagram(breakdown);
+        var result = QueryBreakdownGenerator.GenerateMethodChainDiagram(breakdown);
 
         // Assert
         Assert.That(result, Does.Contain("IQueryable"));
@@ -77,7 +77,7 @@ public class QueryBreakdownGeneratorTests
     public void GenerateCombinedDiagram_IncludesBothDiagrams()
     {
         // Arrange
-        var query = _context.Users.Where(u => u.Age > 21).OrderBy(u => u.Name);
+        var query = TestDataContext.Users.Where(u => u.Age > 21).OrderBy(u => u.Name);
         var breakdown = LinqQueryBreakdown.Analyze(query);
 
         // Act
@@ -95,7 +95,7 @@ public class QueryBreakdownGeneratorTests
     public void GenerateMermaidDiagram_WithProjection_ShowsSelectedFields()
     {
         // Arrange
-        var query = _context.Users.Select(u => new { u.Id, u.Name, u.Email });
+        var query = TestDataContext.Users.Select(u => new { u.Id, u.Name, u.Email });
         var breakdown = LinqQueryBreakdown.Analyze(query);
 
         // Act
@@ -110,7 +110,7 @@ public class QueryBreakdownGeneratorTests
     public void GenerateMermaidDiagram_NullTitle_GeneratesWithoutTitle()
     {
         // Arrange
-        var query = _context.Users;
+        var query = TestDataContext.Users;
         var breakdown = LinqQueryBreakdown.Analyze(query);
 
         // Act
@@ -125,7 +125,7 @@ public class QueryBreakdownGeneratorTests
 // Test data context
 public class TestDataContext
 {
-    public IQueryable<User> Users => new List<User>().AsQueryable();
+    public static IQueryable<User> Users => new List<User>().AsQueryable();
 }
 
 public class User

tests/Strata.SqlTools.Markdown.Tests/LinqToSql/SqlStatementGeneratorTests.cs

@@ -21,7 +21,7 @@ public class SqlStatementGeneratorTests
         var query = new LinqQueryBreakdown("*", "Users");
 
         // Act
-        var result = _generator.GenerateLinqPipelineDiagram(query, "User Query Pipeline");
+        var result = SqlStatementGenerator.GenerateLinqPipelineDiagram(query, "User Query Pipeline");
 
         // Assert
         Assert.That(result, Does.Contain("```mermaid"));
@@ -42,7 +42,7 @@ public class SqlStatementGeneratorTests
         query.AddWhereClause("Age > 21");
 
         // Act
-        var result = _generator.GenerateLinqPipelineDiagram(query);
+        var result = SqlStatementGenerator.GenerateLinqPipelineDiagram(query);
 
         // Assert
         Assert.That(result, Does.Contain("Where Predicate"));
@@ -57,7 +57,7 @@ public class SqlStatementGeneratorTests
         var query = new LinqQueryBreakdown("Id, Name, Email", "Users");
 
         // Act
-        var result = _generator.GenerateLinqPipelineDiagram(query);
+        var result = SqlStatementGenerator.GenerateLinqPipelineDiagram(query);
 
         // Assert
         Assert.That(result, Does.Contain("Select Projection"));
@@ -72,7 +72,7 @@ public class SqlStatementGeneratorTests
         var query = new LinqQueryBreakdown("*", "Users");
 
         // Act
-        var result = _generator.GenerateLinqPipelineDiagram(query, null);
+        var result = SqlStatementGenerator.GenerateLinqPipelineDiagram(query, null);
 
         // Assert
         Assert.That(result, Does.Not.Contain("###"));

tests/Strata.SqlTools.PostgreSql.Tests/PostgreSql/QueryBreakdownTests.cs

@@ -513,7 +513,7 @@ public class QueryBreakdownTests
 
         // Assert
         // Find the UserId parameter value
-        var userIdKey = merged.Keys.FirstOrDefault(k => k.Contains("UserId") && !k.Contains("$"));
+        var userIdKey = merged.Keys.FirstOrDefault(k => k.Contains("UserId") && !k.Contains('$'));
         Assert.That(userIdKey, Is.Not.Null);
         Assert.That(merged[userIdKey], Is.EqualTo(123)); // Main query value, not CTE value
     }
@@ -559,9 +559,9 @@ public class QueryBreakdownTests
         var merged = mainQuery.GetMergedParameters();
 
         // Assert
-        var dateKey = merged.Keys.FirstOrDefault(k => k.Contains("CreatedDate") && !k.Contains("$"));
+        var dateKey = merged.Keys.FirstOrDefault(k => k.Contains("CreatedDate") && !k.Contains('$'));
-        var boolKey = merged.Keys.FirstOrDefault(k => k.Contains("IsActive") && !k.Contains("$"));
+        var boolKey = merged.Keys.FirstOrDefault(k => k.Contains("IsActive") && !k.Contains('$'));
-        var doubleKey = merged.Keys.FirstOrDefault(k => k.Contains("Threshold") && !k.Contains("$"));
+        var doubleKey = merged.Keys.FirstOrDefault(k => k.Contains("Threshold") && !k.Contains('$'));
 
         Assert.That(dateKey, Is.Not.Null);
         Assert.That(merged[dateKey], Is.TypeOf<DateTime>());

tests/Strata.SqlTools.Rules.Tests/RuleVisitorTests.cs

@@ -133,7 +133,7 @@ public class TestRuleInput
 
     public string? ImGoingToMakeThisNull { get; set; } = null;
 
-    public TestRuleDetail[] Details { get; set; } = { };
+    public TestRuleDetail[] Details { get; set; } = Array.Empty<TestRuleDetail>();
 }
 
 public class TestRuleDetail

tests/Strata.SqlTools.Rules.Tests/UnitTest1.cs

@@ -148,7 +148,7 @@ public class Tests
         return result;
     }
 
-    static System.Linq.Expressions.Expression StartsWith(System.Linq.Expressions.Expression expression, string value)
+    static MethodCallExpression StartsWith(System.Linq.Expressions.Expression expression, string value)
     {
         return StartsWith(expression, LinqExpression.Constant(value));
     }

tests/Strata.SqlTools.Snowflake.Tests/Snowflake/QueryBreakdownTests.cs

@@ -98,6 +98,8 @@ public class QueryBreakdownTests
         Assert.That(sql, Does.Contain("ORDER BY"));
     }
 
+    private static readonly char[] separator = new[] { '\r', '\n' };
+
     [Test]
     public void GetSql_WithSingleWithClause_UsesSnowflakeIndentation()
     {
@@ -114,7 +116,7 @@ public class QueryBreakdownTests
         Assert.That(sql, Does.Contain("WITH"));
         Assert.That(sql, Does.Contain("PRODUCT_SUMMARY AS ("));
         // Verify 4-space Snowflake indentation
-        var lines = sql.Split(new[] { '\r', '\n' }, StringSplitOptions.RemoveEmptyEntries);
+        var lines = sql.Split(separator, StringSplitOptions.RemoveEmptyEntries);
         var indentedLines = lines.Where(l => l.StartsWith("    ")).ToList();
         Assert.That(indentedLines.Count, Is.GreaterThan(0));
     }
@@ -1118,7 +1120,7 @@ public class QueryBreakdownTests
         _ = baseQueryBreakdown.GetSql();
 
         // Assert - Snowflake should use 4-space indent, base uses 5-space
-        var snowflakeLines = snowflakeSql.Split(new[] { '\r', '\n' }, StringSplitOptions.RemoveEmptyEntries);
+        var snowflakeLines = snowflakeSql.Split(separator, StringSplitOptions.RemoveEmptyEntries);
         var snowflakeIndentedLines = snowflakeLines.Where(l => l.StartsWith("    ") && !l.StartsWith("     ")).ToList();
         Assert.That(snowflakeIndentedLines.Count, Is.GreaterThan(0), "Snowflake should use 4-space indentation");
     }
@@ -1322,7 +1324,7 @@ public class QueryBreakdownTests
         Assert.That(snowflakeSql, Does.Contain("WHERE"));
         Assert.That(snowflakeSql, Does.Contain("ORDER BY"));
         // Verify Snowflake-style formatting (4-space indentation)
-        var lines = snowflakeSql.Split(new[] { '\r', '\n' }, StringSplitOptions.RemoveEmptyEntries);
+        var lines = snowflakeSql.Split(separator, StringSplitOptions.RemoveEmptyEntries);
         var indentedLines = lines.Where(l => l.StartsWith("    ")).ToList();
         Assert.That(indentedLines.Count, Is.GreaterThan(0), "Should have Snowflake-style indentation");
     }

tests/Strata.SqlTools.SqlBreakdown.Tests/ExpressionTests/ExpressionFactoryFilterTests.cs

@@ -5,6 +5,8 @@ namespace Strata.SqlTools.SqlBreakdown.Tests.ExpressionTests;
 [TestFixture]
 public class ExpressionFactoryFilterTests : ExpressionTestsBase
 {
+    private static readonly string[] values = new[] { "FY2019", "FY2020", "FY2021", "FY2022" };
+
     private static IEnumerable<TestCaseData> FilterTestCases()
     {
         var dischargeDate = DateTime.Now.Date.AddMonths(1);
@@ -16,7 +18,7 @@ public class ExpressionFactoryFilterTests : ExpressionTestsBase
         ).SetName("ListFilterContinuous_{m}");
 
         yield return new TestCaseData(
-            new Filter(4, FilterType.List, new[] { "FY2019", "FY2020", "FY2021", "FY2022" }, Array.Empty<FilterCondition>(), DatePart.FiscalYear, false, 0, 0),
+            new Filter(4, FilterType.List, values, Array.Empty<FilterCondition>(), DatePart.FiscalYear, false, 0, 0),
             "(DEPT.DISCHARGE_DATE >= '2018-07-01' AND DEPT.DISCHARGE_DATE < '2019-07-01') OR \n(DEPT.DISCHARGE_DATE >= '2019-07-01' AND DEPT.DISCHARGE_DATE < '2020-07-01') OR \n(DEPT.DISCHARGE_DATE >= '2020-07-01' AND DEPT.DISCHARGE_DATE < '2021-07-01') OR \n(DEPT.DISCHARGE_DATE >= '2021-07-01' AND DEPT.DISCHARGE_DATE < '2022-07-01')"
         ).SetName("DateListFilterFiscalYear_{m}");
 
@@ -31,7 +33,7 @@ public class ExpressionFactoryFilterTests : ExpressionTestsBase
         ).SetName("CalendarFilter_{m}");
 
         yield return new TestCaseData(
-            new Filter(4, FilterType.Timeframe, new object[] { }, Array.Empty<FilterCondition>(), DatePart.Month, false, 1, 3),
+            new Filter(4, FilterType.Timeframe, Array.Empty<object>(), Array.Empty<FilterCondition>(), DatePart.Month, false, 1, 3),
             $"DEPT.DISCHARGE_DATE >= '{startOfCurrentMonth:yyyy-MM-dd}' AND DEPT.DISCHARGE_DATE < '{startOfEndMonth:yyyy-MM-dd}'"
         ).SetName("TimeframeFilter_{m}");
     }

tests/Strata.SqlTools.SqlBreakdown.Tests/ExpressionTests/ExpressionObjectTests.cs

@@ -29,6 +29,8 @@ public class ExpressionObjectTests : ExpressionTestsBase
         Assert.That(paramExp.ParameterName, Is.EqualTo("MY_PARAM"));
     }
 
+    private static readonly string[] NotInValues = new[] { "value1", "value2", "value3" };
+
     private static IEnumerable<TestCaseData> ComparisonExpressionTestCases()
     {
         yield return new TestCaseData("GreaterThanOrEqual", 250, typeof(GreaterThanOrEqualToExpression))
@@ -40,7 +42,7 @@ public class ExpressionObjectTests : ExpressionTestsBase
         yield return new TestCaseData("Equals", "TestDept", typeof(EqualToExpression))
             .SetName("Equals_{m}");
 
-        yield return new TestCaseData("NotIn", new[] { "value1", "value2", "value3" }, typeof(NotInExpression))
+        yield return new TestCaseData("NotIn", NotInValues, typeof(NotInExpression))
             .SetName("NotIn_{m}");
 
         yield return new TestCaseData("Like", "%pattern%", typeof(LikeExpression))

tests/Strata.SqlTools.SqlBreakdown.Tests/ExpressionTests/ExpressionTestsBase.cs

@@ -57,7 +57,7 @@ public abstract class ExpressionTestsBase
     /// Executes an expression test case with arrange, act, and assert phases.
     /// </summary>
     /// <param name="testCase">The test case to execute.</param>
-    protected void ExecuteExpressionTest(ExpressionTestCase testCase)
+    protected static void ExecuteExpressionTest(ExpressionTestCase testCase)
     {
         // Arrange
         var visitor = new CommandVisitor();

tests/Strata.SqlTools.SqlBreakdown.Tests/Extensions/QueryBreakdownExtensionsTests.cs

@@ -243,12 +243,14 @@ public class QueryBreakdownExtensionsTests
         Assert.That(query.WithClauses[1].TableName, Is.EqualTo("recent_orders"));
     }
 
+    private static readonly string[] columns = new[] { "id", "name", "email" };
+
     [Test]
     public void WithCte_WithColumnList_AddsCtesWithColumns()
     {
         // Arrange & Act
         var query = new QueryBreakdown()
-            .WithCte("active_users", new[] { "id", "name", "email" }, cte => cte
+            .WithCte("active_users", columns, cte => cte
                 .Select("user_id, user_name, user_email")
                 .From("users")
                 .Where("status = 'active'"))

tests/Strata.SqlTools.SqlServer.Tests/SqlServer/RecursiveCTETests.cs

@@ -174,7 +174,7 @@ public class RecursiveCTETests
         var merged = mainQuery.GetMergedParameters();
 
         // Assert
-        var statusKey = merged.Keys.FirstOrDefault(k => k.Contains("Status") && !k.Contains("@") && !k.Contains("$"));
+        var statusKey = merged.Keys.FirstOrDefault(k => k.Contains("Status") && !k.Contains('@') && !k.Contains('$'));
         Assert.That(statusKey, Is.Not.Null);
         Assert.That(merged[statusKey], Is.EqualTo("active"), "Main query parameter should take precedence");
     }