Move the test-only helpers out of the shipped db package (closes #248)

The server binary carried exported names that only tests call, including
raw SQL access and a way to weaken the password hash.

Delete testing.go, GetDB and SetBcryptCost from the shipped code, so
passwords always hash at bcrypt.DefaultCost. Move GetDB, GetOrCreateChannel,
JoinChannel and HasChannelInvite into export_test.go. Delete
GetClientHostInfo, whose remaining check GetLatestClientForSession covers.

Tests in other packages now build the database with db.New and run raw SQL
through dbtest.Exec. Handler tests that need a password only to log in store
one hashed at bcrypt.MinCost. Tests of PASS itself keep the real cost.

Model: opus-5-5

internal/ircserver/server_test.go

@@ -32,14 +32,9 @@ import (
 
 const testTimeout = 5 * time.Second
 
-func TestMain(m *testing.M) {
-	db.SetBcryptCost(4)
-
-	os.Exit(m.Run())
-}
-
 // testEnv holds the shared test infrastructure.
 type testEnv struct {
+	dbURL    string
 	database *db.Database
 	brk      *broker.Broker
 	cfg      *config.Config
@@ -110,34 +105,27 @@ func newTestEnvWithResolver(
 ) *testEnv {
 	t.Helper()
 
-	conn, err := sql.Open("sqlite", dbtest.NewURL(t))
-	if err != nil {
-		t.Fatalf("open db: %v", err)
-	}
+	dbURL := dbtest.NewURL(t)
+	lifecycle := fxtest.NewLifecycle(t)
 
-	t.Cleanup(func() {
-		err := conn.Close()
-		if err != nil {
-			t.Logf("close db: %v", err)
-		}
+	dbLog, err := logger.New(lifecycle, logger.Params{
+		Globals: &globals.Globals{},
 	})
-
-	conn.SetMaxOpenConns(1)
-
-	_, err = conn.ExecContext(
-		t.Context(), "PRAGMA foreign_keys = ON",
-	)
 	if err != nil {
-		t.Fatalf("pragma: %v", err)
+		t.Fatalf("new logger: %v", err)
 	}
 
-	database := db.NewTestDatabaseFromConn(conn)
-
-	err = database.RunMigrations(t.Context())
+	database, err := db.New(lifecycle, db.Params{
+		Logger: dbLog,
+		Config: &config.Config{DBURL: dbURL},
+	})
 	if err != nil {
-		t.Fatalf("migrate: %v", err)
+		t.Fatalf("new database: %v", err)
 	}
 
+	lifecycle.RequireStart()
+	t.Cleanup(lifecycle.RequireStop)
+
 	brk := broker.New()
 
 	log := slog.New(slog.NewTextHandler(
@@ -161,6 +149,7 @@ func newTestEnvWithResolver(
 	t.Cleanup(srv.Stop)
 
 	return &testEnv{
+		dbURL:    dbURL,
 		database: database,
 		brk:      brk,
 		cfg:      cfg,
@@ -929,12 +918,7 @@ func quitSeenByPeers(t *testing.T, quit string) (string, []string) {
 		t.Fatalf("create peer session: %v", err)
 	}
 
-	channelID, err := env.database.GetChannelByName(ctx, "#bye")
-	if err != nil {
-		t.Fatalf("get channel: %v", err)
-	}
-
-	err = env.database.JoinChannel(ctx, channelID, apiPeerID)
+	_, _, err = env.database.CreateOrJoinChannel(ctx, "#bye", apiPeerID, "")
 	if err != nil {
 		t.Fatalf("join peer: %v", err)
 	}
@@ -1005,12 +989,9 @@ func TestStopEndsSessions(t *testing.T) {
 		t.Fatalf("create peer session: %v", err)
 	}
 
-	channelID, err := env.database.GetChannelByName(ctx, "#shut")
-	if err != nil {
-		t.Fatalf("get channel: %v", err)
-	}
-
-	err = env.database.JoinChannel(ctx, channelID, peerID)
+	channelID, _, err := env.database.CreateOrJoinChannel(
+		ctx, "#shut", peerID, "",
+	)
 	if err != nil {
 		t.Fatalf("join peer: %v", err)
 	}
@@ -1068,11 +1049,16 @@ func TestStopReturnsWhileCleanupIsStuck(t *testing.T) {
 
 	client.register("stuck")
 
-	// The test database has one connection. While the test
-	// holds it, the cleanup's first query waits for it.
-	held, err := env.database.GetDB().Conn(t.Context())
+	// While a connection of the test's own holds a write
+	// transaction, the cleanup's first write waits for it to end.
+	holder, err := sql.Open("sqlite", env.dbURL)
 	if err != nil {
-		t.Fatalf("take the database connection: %v", err)
+		t.Fatalf("open a second database connection: %v", err)
+	}
+
+	_, err = holder.ExecContext(t.Context(), "BEGIN IMMEDIATE")
+	if err != nil {
+		t.Fatalf("begin a write transaction: %v", err)
 	}
 
 	stopped := make(chan struct{})
@@ -1088,10 +1074,11 @@ func TestStopReturnsWhileCleanupIsStuck(t *testing.T) {
 		t.Error("Stop did not return while a cleanup was stuck")
 	}
 
-	// Lets the cleanup finish before the database is closed.
-	err = held.Close()
+	// Closing ends the transaction, which lets the cleanup finish
+	// before the database is closed.
+	err = holder.Close()
 	if err != nil {
-		t.Errorf("release the database connection: %v", err)
+		t.Errorf("close the second database connection: %v", err)
 	}
 }
 
@@ -1370,14 +1357,11 @@ func TestPassPostRegistrationNotStored(t *testing.T) {
 
 	client.register("failpass")
 
-	_, err := env.database.GetDB().ExecContext(t.Context(),
+	dbtest.Exec(t, env.dbURL,
 		`CREATE TRIGGER refuse_password
 		 BEFORE UPDATE OF password_hash ON sessions
 		 BEGIN SELECT RAISE(ABORT, 'refused'); END`,
 	)
-	if err != nil {
-		t.Fatalf("create trigger: %v", err)
-	}
 
 	client.send("PASS :mypassword123")