Keep each test database when the pool replaces its connection (closes #209)

SQLite deletes a shared in-memory database when its last connection
closes. A query cancelled while it runs makes the pool close its
connection, so a test could lose all its tables and rows at random.

NewTestDatabaseURL in internal/db returns the URL of a new in-memory
database with a random name. It holds one connection to it open until
the test ends. The db, handlers, ircserver, server and service tests
now take their database URL from it.

A new test cancels a query on such a database, checks with a TEMP
table that the connection was replaced, and checks that a row is
still there.

Model: opus-5-5

.golangci.yml

@@ -61,10 +61,6 @@ linters:
               desc: >-
                 Test-support code belongs in test files and in packages whose
                 directory name ends in test, not in the shipped binary.
-            - pkg: sneak.berlin/go/neoirc/internal/dbtest
-              desc: >-
-                Test-support code belongs in test files and in packages whose
-                directory name ends in test, not in the shipped binary.
     # Only decisions already recorded in the Go package defaults are
     # listed here. Every entry matches the module path exactly.
     gomodguard_v2:

internal/db/db_test.go

@@ -12,7 +12,6 @@ import (
 	"go.uber.org/fx/fxtest"
 	"sneak.berlin/go/neoirc/internal/config"
 	"sneak.berlin/go/neoirc/internal/db"
-	"sneak.berlin/go/neoirc/internal/dbtest"
 	"sneak.berlin/go/neoirc/internal/globals"
 	"sneak.berlin/go/neoirc/internal/logger"
 )
@@ -164,7 +163,7 @@ func TestForeignKeysOnAfterCancelledQuery(t *testing.T) {
 func TestNewTestDatabaseURLKeepsDataAfterCancelledQuery(t *testing.T) {
 	t.Parallel()
 
-	database, err := startDatabase(t, dbtest.NewTestDatabaseURL(t))
+	database, err := startDatabase(t, db.NewTestDatabaseURL(t))
 	if err != nil {
 		t.Fatal(err)
 	}

internal/db/export_test.go

@@ -6,15 +6,13 @@ import (
 	"fmt"
 	"log/slog"
 	"testing"
-
-	"sneak.berlin/go/neoirc/internal/dbtest"
 )
 
 // NewTestDatabase creates an in-memory database for testing.
 func NewTestDatabase(tb testing.TB) (*Database, error) {
 	tb.Helper()
 
-	dsn := dbtest.NewTestDatabaseURL(tb) + "&_pragma=foreign_keys(1)"
+	dsn := NewTestDatabaseURL(tb) + "&_pragma=foreign_keys(1)"
 
 	conn, err := sql.Open("sqlite", dsn)
 	if err != nil {

internal/db/testing.go

@@ -2,10 +2,40 @@ package db
 
 import (
 	"context"
+	"crypto/rand"
 	"database/sql"
 	"log/slog"
+	"testing"
 )
 
+// NewTestDatabaseURL returns the URL of a new, empty in-memory
+// database for one test. SQLite deletes an in-memory database when
+// its last connection closes. A pool closes a connection when a query
+// on it is cancelled while it runs. So this function holds a
+// connection of its own open until the test ends.
+func NewTestDatabaseURL(tb testing.TB) string {
+	tb.Helper()
+
+	// A random name, so that no other test can share the database.
+	dbURL := "file:" + rand.Text() + "?mode=memory&cache=shared"
+
+	pool, err := sql.Open("sqlite", dbURL)
+	if err != nil {
+		tb.Fatalf("open test database: %v", err)
+	}
+
+	tb.Cleanup(func() { _ = pool.Close() })
+
+	conn, err := pool.Conn(tb.Context())
+	if err != nil {
+		tb.Fatalf("connect to test database: %v", err)
+	}
+
+	tb.Cleanup(func() { _ = conn.Close() })
+
+	return dbURL
+}
+
 // NewTestDatabaseFromConn creates a Database wrapping an
 // existing *sql.DB connection.  Intended for integration
 // tests in other packages.

internal/dbtest/dbtest.go

@@ -1,39 +0,0 @@
-// Package dbtest gives each test a database of its own. Only tests
-// may import it.
-package dbtest
-
-import (
-	"crypto/rand"
-	"database/sql"
-	"testing"
-
-	_ "modernc.org/sqlite" // registers the sqlite driver
-)
-
-// NewTestDatabaseURL returns the URL of a new, empty in-memory
-// database for one test. SQLite deletes an in-memory database when
-// its last connection closes. A pool closes a connection when a query
-// on it is cancelled while it runs. So this function holds a
-// connection of its own open until the test ends.
-func NewTestDatabaseURL(tb testing.TB) string {
-	tb.Helper()
-
-	// A random name, so that no other test can share the database.
-	dbURL := "file:" + rand.Text() + "?mode=memory&cache=shared"
-
-	pool, err := sql.Open("sqlite", dbURL)
-	if err != nil {
-		tb.Fatalf("open test database: %v", err)
-	}
-
-	tb.Cleanup(func() { _ = pool.Close() })
-
-	conn, err := pool.Conn(tb.Context())
-	if err != nil {
-		tb.Fatalf("connect to test database: %v", err)
-	}
-
-	tb.Cleanup(func() { _ = conn.Close() })
-
-	return dbURL
-}

internal/handlers/api_test.go

@@ -27,7 +27,6 @@ import (
 	api "sneak.berlin/go/neoirc/internal/cli/api"
 	"sneak.berlin/go/neoirc/internal/config"
 	"sneak.berlin/go/neoirc/internal/db"
-	"sneak.berlin/go/neoirc/internal/dbtest"
 	"sneak.berlin/go/neoirc/internal/globals"
 	"sneak.berlin/go/neoirc/internal/handlers"
 	"sneak.berlin/go/neoirc/internal/hashcash"
@@ -164,7 +163,7 @@ func newTestServerWith(
 	viperMu.Lock()
 	defer viperMu.Unlock()
 
-	dbURL := dbtest.NewTestDatabaseURL(t)
+	dbURL := db.NewTestDatabaseURL(t)
 	copyTemplateDB(t, dbURL)
 
 	var (

internal/ircserver/server_test.go

@@ -19,7 +19,6 @@ import (
 	"sneak.berlin/go/neoirc/internal/broker"
 	"sneak.berlin/go/neoirc/internal/config"
 	"sneak.berlin/go/neoirc/internal/db"
-	"sneak.berlin/go/neoirc/internal/dbtest"
 	"sneak.berlin/go/neoirc/internal/globals"
 	"sneak.berlin/go/neoirc/internal/ircserver"
 	"sneak.berlin/go/neoirc/internal/logger"
@@ -107,7 +106,7 @@ func newTestEnvWithResolver(
 ) *testEnv {
 	t.Helper()
 
-	conn, err := sql.Open("sqlite", dbtest.NewTestDatabaseURL(t))
+	conn, err := sql.Open("sqlite", db.NewTestDatabaseURL(t))
 	if err != nil {
 		t.Fatalf("open db: %v", err)
 	}

internal/server/server_test.go

@@ -18,7 +18,6 @@ import (
 	"sneak.berlin/go/neoirc/internal/broker"
 	"sneak.berlin/go/neoirc/internal/config"
 	"sneak.berlin/go/neoirc/internal/db"
-	"sneak.berlin/go/neoirc/internal/dbtest"
 	"sneak.berlin/go/neoirc/internal/globals"
 	"sneak.berlin/go/neoirc/internal/handlers"
 	"sneak.berlin/go/neoirc/internal/healthcheck"
@@ -241,7 +240,7 @@ func newApp(
 			stats.New,
 		),
 		fx.Decorate(func(cfg *config.Config) *config.Config {
-			cfg.DBURL = dbtest.NewTestDatabaseURL(t)
+			cfg.DBURL = db.NewTestDatabaseURL(t)
 			cfg.Port = port
 
 			return cfg

internal/service/service_test.go

@@ -22,7 +22,6 @@ import (
 	"sneak.berlin/go/neoirc/internal/broker"
 	"sneak.berlin/go/neoirc/internal/config"
 	"sneak.berlin/go/neoirc/internal/db"
-	"sneak.berlin/go/neoirc/internal/dbtest"
 	"sneak.berlin/go/neoirc/internal/globals"
 	"sneak.berlin/go/neoirc/internal/hashcash"
 	"sneak.berlin/go/neoirc/internal/logger"
@@ -46,7 +45,7 @@ type testEnv struct {
 func newTestEnv(t *testing.T) *testEnv {
 	t.Helper()
 
-	dbURL := dbtest.NewTestDatabaseURL(t)
+	dbURL := db.NewTestDatabaseURL(t)
 
 	var (
 		database *db.Database