remove Sleep from TestLockWithContext

state/state.go

@@ -74,6 +74,9 @@ type Locker interface {
 	Unlock(id string) error
 }
 
+// test hook to verify that LockWithContext has attempted a lock
+var postLockHook func()
+
 // Lock the state, using the provided context for timeout and cancellation.
 // This backs off slightly to an upper limit.
 func LockWithContext(ctx context.Context, s State, info *LockInfo) (string, error) {
@@ -96,6 +99,10 @@ func LockWithContext(ctx context.Context, s State, info *LockInfo) (string, erro
 			return "", fmt.Errorf("lock error missing ID: %s", err)
 		}
 
+		if postLockHook != nil {
+			postLockHook()
+		}
+
 		// there's an existing lock, wait and try again
 		select {
 		case <-ctx.Done():

state/state_test.go

@@ -74,11 +74,18 @@ func TestLockWithContext(t *testing.T) {
 		t.Fatal("lock should have failed immediately")
 	}
 
+	// block until LockwithContext has made a first attempt
+	attempted := make(chan struct{})
+	postLockHook = func() {
+		close(attempted)
+		postLockHook = nil
+	}
+
 	// unlock the state during LockWithContext
 	unlocked := make(chan struct{})
 	go func() {
 		defer close(unlocked)
-		time.Sleep(500 * time.Millisecond)
+		<-attempted
 		if err := s.Unlock(id); err != nil {
 			t.Fatal(err)
 		}