Add test for build and runner errors

gaper_test.go

@@ -39,6 +39,35 @@ func TestGaperSetupConfigNoParams(t *testing.T) {
 	assert.Equal(t, args.WatchItems, []string{"."})
 }
 
+func TestGaperBuildError(t *testing.T) {
+	mockBuilder := new(testdata.MockBuilder)
+	mockBuilder.On("Build").Return(errors.New("build-error"))
+	mockRunner := new(testdata.MockRunner)
+	mockWatcher := new(testdata.MockWacther)
+
+	cfg := &Config{}
+
+	chOSSiginal := make(chan os.Signal, 2)
+	err := run(cfg, chOSSiginal, mockBuilder, mockRunner, mockWatcher)
+	assert.NotNil(t, err, "build error")
+	assert.Equal(t, "build error: build-error", err.Error())
+}
+
+func TestGaperRunError(t *testing.T) {
+	mockBuilder := new(testdata.MockBuilder)
+	mockBuilder.On("Build").Return(nil)
+	mockRunner := new(testdata.MockRunner)
+	mockRunner.On("Run").Return(nil, errors.New("runner-error"))
+	mockWatcher := new(testdata.MockWacther)
+
+	cfg := &Config{}
+
+	chOSSiginal := make(chan os.Signal, 2)
+	err := run(cfg, chOSSiginal, mockBuilder, mockRunner, mockWatcher)
+	assert.NotNil(t, err, "runner error")
+	assert.Equal(t, "run error: runner-error", err.Error())
+}
+
 func TestGaperWatcherError(t *testing.T) {
 	mockBuilder := new(testdata.MockBuilder)
 	mockBuilder.On("Build").Return(nil)

testdata/mocks.go

@@ -31,8 +31,12 @@ type MockRunner struct {
 // Run ...
 func (m *MockRunner) Run() (*exec.Cmd, error) {
 	args := m.Called()
-	return args.Get(0).(*exec.Cmd), args.Error(1)
+	cmdArg := args.Get(0)
+	if cmdArg == nil {
+		return nil, args.Error(1)
+	}
 
+	return cmdArg.(*exec.Cmd), args.Error(1)
 }
 
 // Kill ...