test: Add unit and integration tests for API and storage

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

backend/internal/storage/testhelpers_test.go

@@ -0,0 +1,107 @@
+//go:build integration
+
+package storage
+
+import (
+	"context"
+	"fmt"
+	"testing"
+	"time"
+
+	"github.com/testcontainers/testcontainers-go"
+	"github.com/testcontainers/testcontainers-go/modules/postgres"
+	"github.com/testcontainers/testcontainers-go/wait"
+)
+
+// testDB holds the shared database connection for integration tests
+type testDB struct {
+	*DB
+	container *postgres.PostgresContainer
+}
+
+// setupTestDB creates a PostgreSQL container and returns a connected DB instance
+func setupTestDB(t *testing.T) *testDB {
+	t.Helper()
+
+	ctx := context.Background()
+
+	container, err := postgres.Run(ctx,
+		"postgres:16-alpine",
+		postgres.WithDatabase("training_tracker_test"),
+		postgres.WithUsername("test"),
+		postgres.WithPassword("test"),
+		testcontainers.WithWaitStrategy(
+			wait.ForLog("database system is ready to accept connections").
+				WithOccurrence(2).
+				WithStartupTimeout(30*time.Second),
+		),
+	)
+	if err != nil {
+		t.Fatalf("failed to start postgres container: %v", err)
+	}
+
+	connStr, err := container.ConnectionString(ctx, "sslmode=disable")
+	if err != nil {
+		t.Fatalf("failed to get connection string: %v", err)
+	}
+
+	db, err := NewDBWithConnString(ctx, connStr)
+	if err != nil {
+		t.Fatalf("failed to connect to database: %v", err)
+	}
+
+	if err := db.Migrate(ctx); err != nil {
+		t.Fatalf("failed to run migrations: %v", err)
+	}
+
+	return &testDB{
+		DB:        db,
+		container: container,
+	}
+}
+
+// cleanup terminates the container and closes the database connection
+func (tdb *testDB) cleanup(t *testing.T) {
+	t.Helper()
+
+	ctx := context.Background()
+
+	if tdb.DB != nil {
+		tdb.DB.Close()
+	}
+
+	if tdb.container != nil {
+		if err := tdb.container.Terminate(ctx); err != nil {
+			t.Logf("failed to terminate container: %v", err)
+		}
+	}
+}
+
+// truncateTables clears all data from tables for test isolation
+func (tdb *testDB) truncateTables(t *testing.T) {
+	t.Helper()
+
+	ctx := context.Background()
+	tables := []string{"session_entries", "sessions", "plan_exercises", "training_plans", "exercises"}
+
+	for _, table := range tables {
+		_, err := tdb.ExecContext(ctx, fmt.Sprintf("TRUNCATE TABLE %s CASCADE", table))
+		if err != nil {
+			t.Fatalf("failed to truncate %s: %v", table, err)
+		}
+	}
+}
+
+// NewDBWithConnString creates a DB instance with a custom connection string
+func NewDBWithConnString(ctx context.Context, connStr string) (*DB, error) {
+	db, err := openDB(connStr)
+	if err != nil {
+		return nil, err
+	}
+
+	if err := db.PingContext(ctx); err != nil {
+		return nil, fmt.Errorf("failed to ping database: %w", err)
+	}
+
+	return &DB{db}, nil
+}