feat(selfupdate): defer self-replacement until response flushed

internal/selfupdate/selfupdate_test.go

@@ -0,0 +1,87 @@
+package selfupdate_test
+
+import (
+	"context"
+	"errors"
+	"sync"
+	"testing"
+	"time"
+
+	"github.com/shcizo/package-updater/internal/discovery"
+	"github.com/shcizo/package-updater/internal/selfupdate"
+	"github.com/stretchr/testify/require"
+)
+
+type recExec struct {
+	mu     sync.Mutex
+	called bool
+	at     time.Time
+}
+
+func (r *recExec) Execute(_ context.Context, _ discovery.Job) error {
+	r.mu.Lock()
+	r.called = true
+	r.at = time.Now()
+	r.mu.Unlock()
+	return nil
+}
+
+func TestIsSelf(t *testing.T) {
+	require.True(t, selfupdate.IsSelf(
+		discovery.Job{Project: "package-updater", Service: "package-updater"},
+		"package-updater",
+	))
+	require.False(t, selfupdate.IsSelf(
+		discovery.Job{Project: "other", Service: "web"},
+		"package-updater",
+	))
+}
+
+func TestWrap_DefersSelf(t *testing.T) {
+	inner := &recExec{}
+	wrapped := selfupdate.Wrap(inner, "package-updater", 30*time.Millisecond)
+
+	flushed := make(chan time.Time, 1)
+	flush := func() { flushed <- time.Now() }
+
+	job := discovery.Job{Project: "package-updater", Service: "package-updater"}
+	require.NoError(t, wrapped.ExecuteWithFlush(context.Background(), job, flush))
+
+	flushAt := <-flushed
+	inner.mu.Lock()
+	require.True(t, inner.called)
+	require.True(t, inner.at.After(flushAt))
+	inner.mu.Unlock()
+}
+
+func TestWrap_NormalJobIsImmediate(t *testing.T) {
+	inner := &recExec{}
+	wrapped := selfupdate.Wrap(inner, "package-updater", 30*time.Millisecond)
+
+	flushed := make(chan time.Time, 1)
+	flush := func() { flushed <- time.Now() }
+
+	job := discovery.Job{Project: "other", Service: "web"}
+	require.NoError(t, wrapped.ExecuteWithFlush(context.Background(), job, flush))
+
+	inner.mu.Lock()
+	require.True(t, inner.called)
+	inner.mu.Unlock()
+	select {
+	case <-flushed:
+		t.Fatal("flush should not be called for non-self jobs")
+	default:
+	}
+}
+
+func TestWrap_PropagatesError(t *testing.T) {
+	wrapped := selfupdate.Wrap(failExec{}, "x", 1*time.Millisecond)
+	err := wrapped.ExecuteWithFlush(context.Background(), discovery.Job{Project: "other"}, func() {})
+	require.Error(t, err)
+}
+
+type failExec struct{}
+
+func (failExec) Execute(_ context.Context, _ discovery.Job) error {
+	return errors.New("boom")
+}