ae: add test that we run a full before a partial sync

agent/ae/ae_test.go

@@ -3,8 +3,12 @@ package ae
 import (
 	"errors"
 	"fmt"
+	"log"
+	"os"
 	"reflect"
+	"sync"
 	"testing"
+	"time"
 )
 
 func TestAE_scaleFactor(t *testing.T) {
@@ -91,3 +95,58 @@ func TestAE_Pause_ifNotPausedRun(t *testing.T) {
 		t.Fatalf("got error %q want %q", got, want)
 	}
 }
+
+func TestAE_Run_SyncFullBeforeChanges(t *testing.T) {
+	shutdownCh := make(chan struct{})
+	state := &mock{
+		syncChanges: func() error {
+			close(shutdownCh)
+			return nil
+		},
+	}
+
+	// indicate that we have partial changes before starting Run
+	l := testSyncer(state, shutdownCh)
+	l.SyncChanges.Trigger()
+
+	var wg sync.WaitGroup
+	wg.Add(1)
+	go func() {
+		defer wg.Done()
+		l.Run()
+	}()
+	wg.Wait()
+
+	if got, want := state.seq, []string{"full", "changes"}; !reflect.DeepEqual(got, want) {
+		t.Fatalf("got call sequence %v want %v", got, want)
+	}
+}
+
+type mock struct {
+	seq                   []string
+	syncFull, syncChanges func() error
+}
+
+func (m *mock) SyncFull() error {
+	m.seq = append(m.seq, "full")
+	if m.syncFull != nil {
+		return m.syncFull()
+	}
+	return nil
+}
+
+func (m *mock) SyncChanges() error {
+	m.seq = append(m.seq, "changes")
+	if m.syncChanges != nil {
+		return m.syncChanges()
+	}
+	return nil
+}
+
+func testSyncer(state State, shutdownCh chan struct{}) *StateSyncer {
+	logger := log.New(os.Stderr, "", 0)
+	l := NewStateSyncer(state, 0, shutdownCh, logger)
+	l.stagger = func(d time.Duration) time.Duration { return d }
+	l.ClusterSize = func() int { return 1 }
+	return l
+}