feat: mail service

mail/internal/app/app_test.go

@@ -0,0 +1,85 @@
+package app
+
+import (
+	"context"
+	"sync"
+	"testing"
+	"time"
+
+	"galaxy/mail/internal/config"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestAppRunStopsComponentsOnContextCancellation(t *testing.T) {
+	t.Parallel()
+
+	component := &blockingComponent{}
+	app := New(config.Config{ShutdownTimeout: time.Second}, component)
+
+	ctx, cancel := context.WithCancel(context.Background())
+	done := make(chan error, 1)
+	go func() {
+		done <- app.Run(ctx)
+	}()
+
+	require.Eventually(t, func() bool {
+		component.mu.Lock()
+		defer component.mu.Unlock()
+		return component.runStarted
+	}, time.Second, 10*time.Millisecond)
+
+	cancel()
+
+	require.Eventually(t, func() bool {
+		select {
+		case err := <-done:
+			return err == nil
+		default:
+			return false
+		}
+	}, time.Second, 10*time.Millisecond)
+	require.Equal(t, 1, component.shutdownCalls)
+}
+
+func TestAppRunReportsEarlyComponentExit(t *testing.T) {
+	t.Parallel()
+
+	app := New(config.Config{ShutdownTimeout: time.Second}, componentFunc(func(context.Context) error {
+		return nil
+	}))
+
+	err := app.Run(context.Background())
+	require.Error(t, err)
+	require.Contains(t, err.Error(), "exited without error before shutdown")
+}
+
+type blockingComponent struct {
+	mu            sync.Mutex
+	runStarted    bool
+	shutdownCalls int
+}
+
+func (component *blockingComponent) Run(ctx context.Context) error {
+	component.mu.Lock()
+	component.runStarted = true
+	component.mu.Unlock()
+
+	<-ctx.Done()
+	return ctx.Err()
+}
+
+func (component *blockingComponent) Shutdown(context.Context) error {
+	component.shutdownCalls++
+	return nil
+}
+
+type componentFunc func(context.Context) error
+
+func (fn componentFunc) Run(ctx context.Context) error {
+	return fn(ctx)
+}
+
+func (fn componentFunc) Shutdown(context.Context) error {
+	return nil
+}