mocking a vendored dependency

b.go

// $GOPATH/src/a/vendor/b/b.go
package b

import "log"

type Type int

type Interface interface {
	InterfaceMethod(Type)
}

type Implementation struct {
}

func (b Implementation) InterfaceMethod(Type) {
	log.Println("in b implementation")
}

bmocks.go

// Automatically generated by MockGen. DO NOT EDIT!
// Source: b (interfaces: Interface)

package mock_b

import (
	b "b"
	gomock "github.com/golang/mock/gomock"
)

// Mock of Interface interface
type MockInterface struct {
	ctrl     *gomock.Controller
	recorder *_MockInterfaceRecorder
}

// Recorder for MockInterface (not exported)
type _MockInterfaceRecorder struct {
	mock *MockInterface
}

func NewMockInterface(ctrl *gomock.Controller) *MockInterface {
	mock := &MockInterface{ctrl: ctrl}
	mock.recorder = &_MockInterfaceRecorder{mock}
	return mock
}

func (_m *MockInterface) EXPECT() *_MockInterfaceRecorder {
	return _m.recorder
}

func (_m *MockInterface) InterfaceMethod(_param0 b.Type) {
	_m.ctrl.Call(_m, "InterfaceMethod", _param0)
}

func (_mr *_MockInterfaceRecorder) InterfaceMethod(arg0 interface{}) *gomock.Call {
	return _mr.mock.ctrl.RecordCall(_mr.mock, "InterfaceMethod", arg0)
}

main.go

// $GOPATH/src/a/main.go
package main

import "b"

func main() {
	bobj := b.Implementation{}
	var btyp b.Type
	bobj.InterfaceMethod(btyp)
}

bmocks.go generated by mockgen -destination bmocks.go b Interface from this PR golang/mock#28