helper/resource: Show last state in timeout err message

helper/resource/error.go

@@ -40,15 +40,26 @@ func (e *UnexpectedStateError) Error() string {
 // TimeoutError is returned when WaitForState times out
 type TimeoutError struct {
 	LastError     error
+	LastState     string
 	ExpectedState []string
 }
 
 func (e *TimeoutError) Error() string {
-	if e.LastError != nil {
-		return fmt.Sprintf("timeout while waiting for state to become '%s': %s",
-			strings.Join(e.ExpectedState, ", "), e.LastError)
+	expectedState := "resource to be gone"
+	if len(e.ExpectedState) > 0 {
+		expectedState = fmt.Sprintf("state to become '%s'", strings.Join(e.ExpectedState, ", "))
 	}
 
-	return fmt.Sprintf("timeout while waiting for state to become '%s'",
-		strings.Join(e.ExpectedState, ", "))
+	lastState := ""
+	if e.LastState != "" {
+		lastState = fmt.Sprintf(" (last state: '%s')", e.LastState)
+	}
+
+	if e.LastError != nil {
+		return fmt.Sprintf("timeout while waiting for %s%s: %s",
+			expectedState, lastState, e.LastError)
+	}
+
+	return fmt.Sprintf("timeout while waiting for %s%s",
+		expectedState, lastState)
 }

helper/resource/state.go

@@ -63,6 +63,7 @@ func (conf *StateChangeConf) WaitForState() (interface{}, error) {
 
 	var result interface{}
 	var resulterr error
+	var currentState string
 
 	doneCh := make(chan struct{})
 	go func() {
@@ -98,7 +99,6 @@ func (conf *StateChangeConf) WaitForState() (interface{}, error) {
 				}
 			}
 
-			var currentState string
 			result, currentState, err = conf.Refresh()
 			if err != nil {
 				resulterr = err
@@ -168,6 +168,7 @@ func (conf *StateChangeConf) WaitForState() (interface{}, error) {
 	case <-time.After(conf.Timeout):
 		return nil, &TimeoutError{
 			LastError:     resulterr,
+			LastState:     currentState,
 			ExpectedState: conf.Target,
 		}
 	}

helper/resource/state_test.go

@@ -106,7 +106,7 @@ func TestWaitForState_inconsistent_negative(t *testing.T) {
 	if err == nil {
 		t.Fatal("Expected timeout error. No error returned.")
 	}
-	expectedErr := "timeout while waiting for state to become 'done'"
+	expectedErr := "timeout while waiting for state to become 'done' (last state: 'done')"
 	if err.Error() != expectedErr {
 		t.Fatalf("Errors don't match.\nExpected: %q\nGiven: %q\n", expectedErr, err.Error())
 	}
@@ -173,6 +173,28 @@ func TestWaitForState_successEmpty(t *testing.T) {
 	}
 }
 
+func TestWaitForState_failureEmpty(t *testing.T) {
+	conf := &StateChangeConf{
+		Pending:        []string{"pending", "incomplete"},
+		Target:         []string{},
+		NotFoundChecks: 1,
+		Refresh: func() (interface{}, string, error) {
+			return 42, "pending", nil
+		},
+		PollInterval: 10 * time.Millisecond,
+		Timeout:      100 * time.Millisecond,
+	}
+
+	_, err := conf.WaitForState()
+	if err == nil {
+		t.Fatal("Expected timeout error. Got none.")
+	}
+	expectedErr := "timeout while waiting for resource to be gone (last state: 'pending')"
+	if err.Error() != expectedErr {
+		t.Fatalf("Errors don't match.\nExpected: %q\nGiven: %q\n", expectedErr, err.Error())
+	}
+}
+
 func TestWaitForState_failure(t *testing.T) {
 	conf := &StateChangeConf{
 		Pending: []string{"pending", "incomplete"},