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.

The new package internal/dbtest has NewURL. It returns the URL of a
new in-memory database with a random name and holds one connection to
it open until the test ends. The db, handlers, ircserver, server and
service tests take their database URL from it. The test-support lint
rule keeps the package out of the server binary.

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

README.md

@@ -3342,6 +3342,7 @@ neoirc/
 │   │   └── schema/
 │   │       ├── 000.sql     # schema_migrations bootstrap
 │   │       └── 001_initial.sql
+│   ├── dbtest/             # Gives each test its own database; only tests import it
 │   ├── globals/            # Application-wide metadata
 │   │   └── globals.go
 │   ├── handlers/           # HTTP request handlers

internal/db/db_test.go

@@ -156,15 +156,15 @@ func TestForeignKeysOnAfterCancelledQuery(t *testing.T) {
 	}
 }
 
-// TestNewTestDatabaseURLKeepsDataAfterCancelledQuery cancels a query
+// TestNewURLKeepsDataAfterCancelledQuery cancels a query on a test
-// on a test database while it runs, which makes the pool close its
+// database while it runs, which makes the pool close its only
-// only connection and open a new one. A TEMP table lasts only as long
+// connection and open a new one. A TEMP table lasts only as long as
-// as its connection, so its absence shows the connection was replaced.
+// its connection, so its absence shows the connection was replaced.
 // The database must still have its tables and rows.
-func TestNewTestDatabaseURLKeepsDataAfterCancelledQuery(t *testing.T) {
+func TestNewURLKeepsDataAfterCancelledQuery(t *testing.T) {
 	t.Parallel()
 
-	database, err := startDatabase(t, dbtest.NewTestDatabaseURL(t))
+	database, err := startDatabase(t, dbtest.NewURL(t))
 	if err != nil {
 		t.Fatal(err)
 	}

internal/db/export_test.go

@@ -14,7 +14,7 @@ import (
 func NewTestDatabase(tb testing.TB) (*Database, error) {
 	tb.Helper()
 
-	dsn := dbtest.NewTestDatabaseURL(tb) + "&_pragma=foreign_keys(1)"
+	dsn := dbtest.NewURL(tb) + "&_pragma=foreign_keys(1)"
 
 	conn, err := sql.Open("sqlite", dsn)
 	if err != nil {

internal/dbtest/dbtest.go

@@ -10,12 +10,12 @@ import (
 	_ "modernc.org/sqlite" // registers the sqlite driver
 )
 
-// NewTestDatabaseURL returns the URL of a new, empty in-memory
+// NewURL returns the URL of a new, empty in-memory database for one
-// database for one test. SQLite deletes an in-memory database when
+// test. SQLite deletes an in-memory database when its last connection
-// its last connection closes. A pool closes a connection when a query
+// closes. A pool closes a connection when a query on it is cancelled
-// on it is cancelled while it runs. So this function holds a
+// while it runs. So this function holds a connection of its own open
-// connection of its own open until the test ends.
+// until the test ends.
-func NewTestDatabaseURL(tb testing.TB) string {
+func NewURL(tb testing.TB) string {
 	tb.Helper()
 
 	// A random name, so that no other test can share the database.

internal/handlers/api_test.go

@@ -164,7 +164,7 @@ func newTestServerWith(
 	viperMu.Lock()
 	defer viperMu.Unlock()
 
-	dbURL := dbtest.NewTestDatabaseURL(t)
+	dbURL := dbtest.NewURL(t)
 	copyTemplateDB(t, dbURL)
 
 	var (

internal/ircserver/server_test.go

@@ -107,7 +107,7 @@ func newTestEnvWithResolver(
 ) *testEnv {
 	t.Helper()
 
-	conn, err := sql.Open("sqlite", dbtest.NewTestDatabaseURL(t))
+	conn, err := sql.Open("sqlite", dbtest.NewURL(t))
 	if err != nil {
 		t.Fatalf("open db: %v", err)
 	}

internal/server/server_test.go

@@ -241,7 +241,7 @@ func newApp(
 			stats.New,
 		),
 		fx.Decorate(func(cfg *config.Config) *config.Config {
-			cfg.DBURL = dbtest.NewTestDatabaseURL(t)
+			cfg.DBURL = dbtest.NewURL(t)
 			cfg.Port = port
 
 			return cfg

internal/service/service_test.go

@@ -46,7 +46,7 @@ type testEnv struct {
 func newTestEnv(t *testing.T) *testEnv {
 	t.Helper()
 
-	dbURL := dbtest.NewTestDatabaseURL(t)
+	dbURL := dbtest.NewURL(t)
 
 	var (
 		database *db.Database