test(e2e): give the suite a throwaway database of its own (#186)

The e2e suite ran against the development database and nothing truncated it. Every run seeded more fixtures and left them, so the unfiltered storefront grew monotonically — 1,662 items by the time #186 was filed — until rendering it outran the assertions' timeouts. It failed locally, passed in CI where the database is fresh, and got steadily worse, which is the combination nobody can act on.

start-local.ps1 -E2eDb runs the stack against a separate container on a separate port with tmpfs storage, so it starts empty every time. Migrations already run on every start, so an empty volume is a working one. The development database is untouched, so anything set up there by hand survives.

Deliberately a third database rather than sharing either existing one. The integration suite truncates between tests, so an e2e run sharing with it would have its fixtures deleted underneath it (#116) — different container, different port, different credentials, so the mistake is impossible rather than discouraged.

Verified by recreating the database from the compose file, confirming it came up with zero items, and running the full suite against it: 157 of 157. An earlier attempt at this reported 23 passed and 53 not run, which was worthless — a stale backend from a previous run still held port 3000 and was talking to a database I had already deleted. The port is checked before the run now, and the same mistake produced a wrong rate-limiter measurement earlier in this work.

Pagination is the other half of #186 and is filed separately: a shop that renders its whole catalogue in one page is worth fixing on its own merits, not as a side effect of a test fix.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

scripts/run-tests.ps1

@@ -18,7 +18,15 @@
     integration  Backend Jest integration tests against a disposable Postgres.
                  Brings the container up itself.
     e2e          Frontend Playwright tests. Needs the app stack up; start it
-                 with .\scripts\start-local.ps1 first.
+                 with .\scripts\start-local.ps1 -E2eDb first.
+
+                 -E2eDb matters. Without it the suite runs against the
+                 development database, which nothing truncates: every run seeds
+                 more fixtures and leaves them, the unfiltered storefront grows
+                 monotonically, and eventually rendering it outruns the
+                 assertions' timeout. It then fails locally, passes in CI where
+                 the database is fresh, and gets worse (#186). With it, the
+                 stack runs against a throwaway database that starts empty.
     all          All three, in that order — cheapest and most isolated first,
                  so a failure that a later suite would also show up in is
                  reported by the suite that localises it best.

scripts/start-local.ps1

@@ -35,6 +35,19 @@ param(
     [int]$ApiPort = 3000,
     [int]$WebPort = 5173,
     [switch]$Fresh,
+    # Runs the stack against the throwaway end-to-end database instead of the
+    # development one: a separate container on a separate port, with tmpfs
+    # storage, so it starts empty every time.
+    #
+    # The e2e suite used to run against the development database, and nothing
+    # ever truncated it. Every run seeded more fixtures and left them, so the
+    # unfiltered storefront grew monotonically — 1,662 items by the time #186
+    # was filed — until rendering it outran the assertions' timeout. It failed
+    # locally, passed in CI where the database is fresh, and got steadily worse.
+    #
+    # This does not touch the development database, so anything you have set up
+    # there by hand survives.
+    [switch]$E2eDb,
     [switch]$Stop,
     # What -Stop puts the machine back to. nvm's default here is 18.16.1, which
     # is too old to run this project's tooling but is what everything else on
@@ -52,10 +65,25 @@ $ErrorActionPreference = 'Stop'
 $RepoRoot = Split-Path -Parent $PSScriptRoot
 $StateDir = Join-Path $RepoRoot '.local'
 $PidFile = Join-Path $StateDir 'pids.json'
-$Container = 'redefined-designs-local-db'
-$DbUser = 'redefined_local'
-$DbPassword = 'redefined_local'
-$DbName = 'redefined_local'
+# Which database this run uses. Everything downstream reads these four, so the
+# choice is made once here rather than branched at each use.
+if ($E2eDb) {
+    $Container = 'redefined-designs-e2e-db'
+    $DbUser = 'redefined_e2e'
+    $DbPassword = 'redefined_e2e'
+    $DbName = 'redefined_e2e'
+    # Not 55500 (development) and not 55432 (the integration suite). The three
+    # must not collide: the integration suite truncates between tests, so
+    # sharing a database with an e2e run would delete that run's fixtures
+    # underneath it (#116).
+    if (-not $PSBoundParameters.ContainsKey('DbPort')) { $DbPort = 55501 }
+}
+else {
+    $Container = 'redefined-designs-local-db'
+    $DbUser = 'redefined_local'
+    $DbPassword = 'redefined_local'
+    $DbName = 'redefined_local'
+}
 
 function Write-Step { param([string]$Message) Write-Host "==> $Message" -ForegroundColor Cyan }
 function Write-Note { param([string]$Message) Write-Host "    $Message" -ForegroundColor DarkGray }
@@ -165,11 +193,19 @@ function Start-Database {
     }
     else {
         Write-Step "Creating the database container on port $DbPort"
+        # tmpfs for the e2e database only: its contents are worthless the
+        # moment the run ends, and storing nothing is what makes it start empty
+        # every time rather than accumulating fixtures the way the development
+        # database did (#186). Migrations run on every start below, so an empty
+        # volume is a working one. The development database keeps its storage.
+        $storage = if ($E2eDb) { @('--tmpfs', '/var/lib/postgresql/data') } else { @() }
+
         docker run -d --name $Container `
             -e "POSTGRES_USER=$DbUser" `
             -e "POSTGRES_PASSWORD=$DbPassword" `
             -e "POSTGRES_DB=$DbName" `
             -p "${DbPort}:5432" `
+            @storage `
             postgres:16 *>$null
 
         if ($LASTEXITCODE -ne 0) {