stuff_test.go

package stuff

import (
	"github.com/stretchr/testify/mock"
	"testing"
)

// Interface to mock
type Stuff interface {
	DoThings(fu, bar string) (string, error)
}

// Function under test
func DoThingsWithStuff(s Stuff) (string, error) {
	return s.DoThings("hello", "world")
}

// Test code

type MockedStuff struct {
	mock.Mock
}

func (m *MockedStuff) DoThings(fu, bar string) (string, error) {
	args := m.Called(fu, bar)
	return args.String(0), args.Error(1)

}

// Causes index out of range
func TestDoThingsWithStuffDoesThingsWithoutArgs(t *testing.T) {
	mocked_stuff := new(MockedStuff)
	mocked_stuff.On("DoThings").Return("did things", nil)
	DoThingsWithStuff(mocked_stuff)
}

// Correct
func TestDoThingsWithStuffActualyDoesWithArgs(t *testing.T) {
	mocked_stuff := new(MockedStuff)
	mocked_stuff.On("DoThings", mock.Anything, mock.Anything).Return("did things", nil)
	DoThingsWithStuff(mocked_stuff)
}