fix: strip port/proto suffix in wait.ForSQL URL callback

.github/workflows/test.yml

@@ -0,0 +1,22 @@
+name: Test
+
+on:
+  push:
+    branches: [master]
+  pull_request:
+    branches: [master]
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Setup Go
+        uses: actions/setup-go@v5
+        with:
+          go-version-file: 'go.mod'
+          cache-dependency-path: 'go.sum'
+
+      - name: Run tests
+        run: go test -race -v -timeout=3m ./...

container.go

@@ -345,7 +345,10 @@ func setupPostgresTestContainer(ctx context.Context, cfg Config) (testcontainers
 			"/var/lib/pg/data": "rw",
 		},
 		WaitingFor: wait.ForSQL(port, "pgx", func(host string, port string) string {
-			return fmt.Sprintf("postgres://%s:%s@%s:%s/%s?sslmode=disable", cfg.User, cfg.Password, host, port, cfg.Database)
+			// testcontainers-go v0.42 passes the port as "<num>/<proto>" (e.g. "5432/tcp").
+			// Strip the protocol suffix so it doesn't leak into the URL path and corrupt the dbname.
+			portNum, _, _ := strings.Cut(port, "/")
+			return fmt.Sprintf("postgres://%s:%s@%s:%s/%s?sslmode=disable", cfg.User, cfg.Password, host, portNum, cfg.Database)
 		}).WithStartupTimeout(10 * time.Second),
 	}
 
@@ -371,5 +374,5 @@ type SlogAdapter struct {
 }
 
 func (s *SlogAdapter) Printf(format string, v ...any) {
-	s.logger.Info(fmt.Sprintf(format, v))
+	s.logger.Info(fmt.Sprintf(format, v...))
 }

container_test.go

@@ -0,0 +1,102 @@
+package brrr_test
+
+import (
+	"context"
+	"os"
+	"testing"
+	"time"
+
+	"github.com/modfin/brrr"
+)
+
+var testContainer *brrr.Container
+
+func TestMain(m *testing.M) {
+	c, err := brrr.NewContainer(brrr.Config{
+		User:     "postgres",
+		Password: "postgres",
+		Database: "brrr_test",
+	})
+	if err != nil {
+		panic("failed to start test container: " + err.Error())
+	}
+	testContainer = c
+	code := m.Run()
+	if err := c.Close(); err != nil {
+		panic("failed to close test container: " + err.Error())
+	}
+	os.Exit(code)
+}
+
+// TestNewContainer_StartsCleanly is the regression test for the wait.ForSQL URL
+// construction bug introduced when testcontainers-go migrated to moby modules in
+// v0.42. The callback was receiving the port as "<num>/<proto>" (e.g. "5432/tcp"),
+// and embedding the suffix into the URL path, which corrupted the dbname and made
+// the SQL wait strategy fail until the 10s startup timeout expired.
+// If TestMain completes successfully, this test passes; it exists to name the
+// guarantee explicitly so future regressions surface as a named failure.
+func TestNewContainer_StartsCleanly(t *testing.T) {
+	if testContainer == nil {
+		t.Fatal("test container was not initialized in TestMain")
+	}
+}
+
+func TestContainer_NewInstance_IsUsable(t *testing.T) {
+	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
+	defer cancel()
+
+	di, err := testContainer.NewInstance(ctx)
+	if err != nil {
+		t.Fatalf("NewInstance: %v", err)
+	}
+	t.Cleanup(func() {
+		if err := testContainer.CloseInstance(context.Background(), di); err != nil {
+			t.Errorf("CloseInstance: %v", err)
+		}
+	})
+
+	var got int
+	if err := di.Connection.QueryRow(ctx, "SELECT 1").Scan(&got); err != nil {
+		t.Fatalf("SELECT 1 against instance failed: %v", err)
+	}
+	if got != 1 {
+		t.Fatalf("expected 1, got %d", got)
+	}
+}
+
+func TestContainer_NewInstance_InstancesAreIsolated(t *testing.T) {
+	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
+	defer cancel()
+
+	a, err := testContainer.NewInstance(ctx)
+	if err != nil {
+		t.Fatalf("NewInstance a: %v", err)
+	}
+	t.Cleanup(func() { _ = testContainer.CloseInstance(context.Background(), a) })
+
+	b, err := testContainer.NewInstance(ctx)
+	if err != nil {
+		t.Fatalf("NewInstance b: %v", err)
+	}
+	t.Cleanup(func() { _ = testContainer.CloseInstance(context.Background(), b) })
+
+	if a.Name == b.Name {
+		t.Fatalf("expected distinct instance names, both were %q", a.Name)
+	}
+
+	if _, err := a.Connection.Exec(ctx, "CREATE TABLE isolation_probe (v int)"); err != nil {
+		t.Fatalf("create table on a: %v", err)
+	}
+	if _, err := a.Connection.Exec(ctx, "INSERT INTO isolation_probe (v) VALUES (42)"); err != nil {
+		t.Fatalf("insert on a: %v", err)
+	}
+
+	var exists bool
+	err = b.Connection.QueryRow(ctx, "SELECT EXISTS (SELECT 1 FROM information_schema.tables WHERE table_name = 'isolation_probe')").Scan(&exists)
+	if err != nil {
+		t.Fatalf("lookup on b: %v", err)
+	}
+	if exists {
+		t.Fatal("expected isolation_probe to not exist on instance b; template contamination")
+	}
+}