mocaccino

Mocaccino

Mocaccino is a mocking framework for the Go programming language in the same fashion as gomock. However, typed stubs is available, and chaining is supported. This library is heavily inspired by the aforementioned project.

Installation

First, install mocagen:

go install github.com/heyvito/mocaccino/mocagen@latest

Generating Stubs

The mocagen utility is responsible for generating code based on either source files, or external packages present in your go.mod.

Providing Source Files

The simplest call to the codegen utility takes an output directory through the -o parameter, an input file, and a list of interfaces to have stubs generated.

mocagen -o mocks ./my_interface.go MyInterface

Alternatively, when generating stubs from source files, mocagen provides a way to generate stubs for all interfaces present in the source file by providing a single all interface instead of a list:

mocagen -o mocks ./my_interface.go all

Providing External Packages

In order to generate stubs from external packages declared in your go.mod, simply provide the package name instead of a file path:

mocagen -o mocks github.com/someuser/somepackage InterfaceA InterfaceB

Available Arguments

--package NAME: Package to be used when generating sources. If absent, will be inferred from --out

--rename OLD=NEW[,OLD=NEW[,...]]: Assigns new names to generated interfaces. Renames OLD to NEW when generating stubs.

--out PATH: Sets the path to the directory in which sources will be generated. Directories will be created as required in case they don't exist. Required.

Using Stubs

gomock users will find the interface provided by Mocaccino quite familiar. First, create a Controller, then create a mock instance by calling the New function associated with the name of a generated stub. For instance:

// impl.go

package example

//go:generate mocagen -o . impl.go Service

type User struct {
	Name    string
	Address string
}

type Message struct {
	Subject string
	Body    string
}

type RandomService interface {
	PerformAdd(a, b int) (int, error)
	PerformSend(user *User, mail *Message) error
}

// impl_test.go

package example

import (
	"github.com/heyvito/mocaccino"
	"github.com/stretchr/testify/require"
	"testing"
)

func TestSimpleCall(t *testing.T) {
	ctrl := mocaccino.NewController(t)
	mock := NewRandomServiceMock(ctrl)
	mock.EXPECT().PerformAdd().With(1, 2).Return(3, nil)

	result, err := mock.PerformAdd(1, 2)
	require.NoError(t, err)
	require.Equal(t, 3, result)
}