update to add tests

datastores/sql/migrate/migrate_test.go

@@ -0,0 +1,206 @@
+package migrate
+
+import (
+	"context"
+	"database/sql"
+	"os"
+	"path/filepath"
+	"testing"
+
+	_ "modernc.org/sqlite"
+)
+
+// sqliteDialect implements Dialect for SQLite.
+type sqliteDialect struct{}
+
+func (sqliteDialect) Placeholder(n int) string { return "?" }
+
+func (sqliteDialect) TableExistsQuery() string {
+	return "SELECT EXISTS (SELECT 1 FROM sqlite_master WHERE type='table' AND name = ?)"
+}
+
+func openTestDB(t *testing.T) *sql.DB {
+	t.Helper()
+	db, err := sql.Open("sqlite", ":memory:")
+	if err != nil {
+		t.Fatalf("open sqlite: %v", err)
+	}
+	t.Cleanup(func() { db.Close() })
+	return db
+}
+
+// writeMigrations creates .up.sql files in dir and returns the directory path.
+func writeMigrations(t *testing.T, files map[string]string) string {
+	t.Helper()
+	dir := t.TempDir()
+	for name, content := range files {
+		if err := os.WriteFile(filepath.Join(dir, name), []byte(content), 0o644); err != nil {
+			t.Fatalf("write migration %s: %v", name, err)
+		}
+	}
+	return dir
+}
+
+func TestDiscoverMigrations(t *testing.T) {
+	dir := writeMigrations(t, map[string]string{
+		"000002_create_posts.up.sql":   "CREATE TABLE posts (id INTEGER);",
+		"000001_create_users.up.sql":   "CREATE TABLE users (id INTEGER);",
+		"000001_create_users.down.sql": "DROP TABLE users;",
+		"README.md":                    "not a migration",
+	})
+
+	got, err := discoverMigrations(dir)
+	if err != nil {
+		t.Fatalf("discoverMigrations: %v", err)
+	}
+
+	want := []string{
+		"000001_create_users.up.sql",
+		"000002_create_posts.up.sql",
+	}
+	if len(got) != len(want) {
+		t.Fatalf("got %d migrations, want %d", len(got), len(want))
+	}
+	for i := range want {
+		if got[i] != want[i] {
+			t.Errorf("migration[%d] = %q, want %q", i, got[i], want[i])
+		}
+	}
+}
+
+func TestDiscoverMigrations_empty(t *testing.T) {
+	dir := t.TempDir()
+
+	got, err := discoverMigrations(dir)
+	if err != nil {
+		t.Fatalf("discoverMigrations: %v", err)
+	}
+	if got != nil {
+		t.Fatalf("got %v, want nil", got)
+	}
+}
+
+func TestRun(t *testing.T) {
+	db := openTestDB(t)
+	ctx := context.Background()
+	dialect := sqliteDialect{}
+
+	dir := writeMigrations(t, map[string]string{
+		"000001_create_users.up.sql": "CREATE TABLE users (id INTEGER PRIMARY KEY, name TEXT);",
+		"000002_create_posts.up.sql": "CREATE TABLE posts (id INTEGER PRIMARY KEY, user_id INTEGER);",
+	})
+
+	err := Run(ctx, db, dialect, &Options{MigrationsDir: dir})
+	if err != nil {
+		t.Fatalf("Run: %v", err)
+	}
+
+	// Verify tables were created.
+	for _, table := range []string{"users", "posts", "schema_migrations"} {
+		if !tableExists(ctx, db, dialect, table) {
+			t.Errorf("table %q should exist", table)
+		}
+	}
+
+	// Verify migration records.
+	applied, err := getAppliedMigrations(ctx, db)
+	if err != nil {
+		t.Fatalf("getAppliedMigrations: %v", err)
+	}
+	if !applied["000001_create_users.up.sql"] || !applied["000002_create_posts.up.sql"] {
+		t.Errorf("applied = %v, want both migrations", applied)
+	}
+}
+
+func TestRun_idempotent(t *testing.T) {
+	db := openTestDB(t)
+	ctx := context.Background()
+	dialect := sqliteDialect{}
+
+	dir := writeMigrations(t, map[string]string{
+		"000001_create_users.up.sql": "CREATE TABLE users (id INTEGER PRIMARY KEY);",
+	})
+
+	opts := &Options{MigrationsDir: dir}
+
+	if err := Run(ctx, db, dialect, opts); err != nil {
+		t.Fatalf("first Run: %v", err)
+	}
+	if err := Run(ctx, db, dialect, opts); err != nil {
+		t.Fatalf("second Run: %v", err)
+	}
+
+	// Still only one record.
+	applied, err := getAppliedMigrations(ctx, db)
+	if err != nil {
+		t.Fatalf("getAppliedMigrations: %v", err)
+	}
+	if len(applied) != 1 {
+		t.Errorf("got %d applied migrations, want 1", len(applied))
+	}
+}
+
+func TestRun_nilOpts(t *testing.T) {
+	db := openTestDB(t)
+	ctx := context.Background()
+	dialect := sqliteDialect{}
+
+	// nil opts should not panic; it will use cwd/migrations which won't exist,
+	// so we expect an error but not a panic.
+	err := Run(ctx, db, dialect, nil)
+	if err == nil {
+		t.Fatal("expected error with nil opts (no migrations dir), got nil")
+	}
+}
+
+func TestRun_bootstrap(t *testing.T) {
+	db := openTestDB(t)
+	ctx := context.Background()
+	dialect := sqliteDialect{}
+
+	// Create the sentinel table to simulate an existing schema.
+	if _, err := db.ExecContext(ctx, "CREATE TABLE my_app (id INTEGER)"); err != nil {
+		t.Fatalf("create sentinel: %v", err)
+	}
+
+	dir := writeMigrations(t, map[string]string{
+		"000001_create_users.up.sql": "CREATE TABLE users (id INTEGER PRIMARY KEY);",
+		"000002_create_posts.up.sql": "CREATE TABLE posts (id INTEGER PRIMARY KEY);",
+	})
+
+	err := Run(ctx, db, dialect, &Options{
+		MigrationsDir:  dir,
+		BootstrapTable: "my_app",
+	})
+	if err != nil {
+		t.Fatalf("Run: %v", err)
+	}
+
+	// Migrations should be recorded but NOT executed (tables should not exist).
+	applied, err := getAppliedMigrations(ctx, db)
+	if err != nil {
+		t.Fatalf("getAppliedMigrations: %v", err)
+	}
+	if len(applied) != 2 {
+		t.Fatalf("got %d applied, want 2 (bootstrapped)", len(applied))
+	}
+
+	// The actual tables should NOT have been created.
+	if tableExists(ctx, db, dialect, "users") {
+		t.Error("users table should not exist after bootstrap")
+	}
+	if tableExists(ctx, db, dialect, "posts") {
+		t.Error("posts table should not exist after bootstrap")
+	}
+}
+
+func TestRun_noMigrationsDir(t *testing.T) {
+	db := openTestDB(t)
+	ctx := context.Background()
+	dialect := sqliteDialect{}
+
+	err := Run(ctx, db, dialect, &Options{MigrationsDir: "/nonexistent/path"})
+	if err == nil {
+		t.Fatal("expected error for nonexistent dir, got nil")
+	}
+}