Comparison of golang mocking libraries

golang-mocks.md

Comparison of golang mocking libraries

Updated 2025-04-13

	gomock	testify + mockery	mockio	minimock	moq
Library
GitHub stars		+
Latest release date		+
Maintained	✅	✅	✅	✅	✅
Notes	1	2	3
Mock creation
Code generation 4	✅	✅	✖️	✅	✅
Works without code generation 5	❌	✅	✅	❌	❌
Use t.Cleanup() 6	✅	✅	✅	✅	❌
Support generics	✅	✅	✅	✅	✅
DSL
Execute custom func 7	✅	✅	✅	✅	✅
Calls order 8	✅	✅	❌	❌	❌
Wait for time.Duration 9	❌	✅	❌	❌	❌
Wait for message from chan 10	❌	✅	❌	❌	❌
Panic 11	❌	✅	❌	❌	❌
Assert expectations with timeout	❌	❌	❌	✅	❌
Return zero values by default 12	✅	❌	✅	❌	❌
Capturer 13	❌	✅	✅	✅	✅
Calls count
Exact calls count 14	✅	✅	✅	✅	❌
Min/max calls count 15	✅	❌	❌	❌	❌
Called at least once	✅	❌	✅	❌	❌
Don't check calls count	✅	✅	✅	✅	❌
Expect once by default 16	✅	❌	❌	❌	❌
Matchers
Any value	✅	✅	✅	✅	❌
Equal to (reflect)	✅	✅	✅	✅	❌
Not equal to	✅	❌	✅	❌	❌
Exact (==)	❌	❌	✅	❌	❌
One of values	✅	❌	✅	❌	❌
Regex	✅	❌	✅	❌	❌
Substring	❌	❌	✅	❌	❌
Is nil	✅	❌	✅	❌	❌
Not nil	✅	❌	✅	❌	❌
Type is	✅	✅	✅	❌	❌
Length is	✅	❌	✔️ 17	❌	❌
Slice elements in any order	✅	❌	✅	❌	❌
Slice contains	❌	❌	✅	❌	❌
Map contains keys	❌	❌	✅	❌	❌
Functional options	❌	✅	❌	❌	❌
Logical operations on matchers	✅	❌	❌	❌	❌
Custom matcher	✅	✅	✅	✅	❌

Examples

gomock

func TestUberGomock(t *testing.T) {
	ctrl := gomock.NewController(t)
	m := NewMockMyInterface(ctrl)
	gomock.InOrder(
		m.EXPECT().Method(gomock.Any(), "abc").Return(123, nil),
		m.EXPECT().AnotherMethod(gomock.Any(), gomock.Len(3)),
	)
	...
}

testify/mock + mockery

func TestTestifyMock(t *testing.T) {
	m := mocks.NewMyInterface(t)
	m.EXPECT().Method(mock.Anything, "abc").After(5*time.Second).Return(123, nil).Once()
	m.EXPECT().AnotherMethod(mock.Anything, "abc").Return(0, nil).Once()
	...
}

mockio

func TestMockio(t *testing.T) {
	ctrl := mock.NewMockController(t, mockopts.StrictVerify())
	m := mock.Mock[MyInterface](ctrl)
	mock.WhenDouble(m.Method(mock.AnyContext(), mock.Equal("abc"))).ThenReturn(123, nil).Verify(mock.Once())
	mock.WhenDouble(m.AnotherMethod(mock.AnyContext(), mock.Regex("ab?c"))).Verify(mock.Once())
	captor := mock.Captor[string]()
	mock.WhenDouble(m.Method(mock.AnyContext(), captor.Capture()))
	...
	assert.Equal(t, "abc", captor.Last())
}

minimock

func TestMinimock(t *testing.T) {
	ctrl := minimock.NewController(t)
	m := NewMyInterfaceMock(ctrl)
	m.MethodMock.When(minimock.AnyContext, "abc").Then(123, nil)
	m.AnotherMethodMock.When(minimock.AnyContext, "abc").Then(0, nil)
	...
}

moq

func TestMoq(t *testing.T) {
	m := MyInterfaceMock{
		MethodFunc: func(ctx context.Context, s string) (int, error) {
			assert.Equal(t, "abc", s)
			return 123, nil
		},
		AnotherMethodFunc: func(ctx context.Context, s string) (int, error) {
			assert.Len(t, s, 1)
			return 0, nil
		},
	}
	t.Cleanup(func() {
		assert.Len(t, m.MethodCalls(), 1)
		assert.Len(t, m.AnotherMethodCalls(), 1)
	})
	...
}

Footnotes

1. Google stopped maintaining the original gomock with 9K stars, Uber forked it and continue development ↩

2. mockery, starting from v3, became a generic interface-based code generation framework, see blog post ↩

3. mockio supports only amd64 and arm64 processors and it heavily depends on compiler internals and unsafe package, see docs ↩

4. CLI tool to auto generate mocks from interfaces ↩

5. Create mocks in runtime, without code generation ↩

6. Mock constructor uses t.Cleanup() to assert expectations after test by default ↩

7. Use arbitrary function to execute, allowing to implement any feature in the table ↩

8. Define expected order of calls ↩

9. Block execution of method using time.Sleep() ↩

10. Block execution of method using <- channel ↩

11. Panic instead of method execution ↩

12. Not defining return values leads to returning zero values ↩

13. Ability to capture actual call arguments to validate them later (not in mock) ↩

14. Define expected exact number of calls in test ↩

15. Define expected min/max number of calls in test ↩

16. Not defining number of calls leads to expectation that method to be called once ↩

17. There are only length matchers for slices and maps, not for strings ↩

@LandonTClipp, thanks for pointing me this. Most probably, the wording in the table needs to be better. Typed expected arguments means that a method to define expectation is typed. The RunAndReturn method doesn't define an expectation. In your example, the method Get does it, and it accepts any.

But I've removed the wrong checkmark in Uber gomock for that feature.

Actually, I realized that having Typed expected arguments means not having matches at all.

UPD: The last statement is incorrect as mockio has matchers, and it's strictly typed at the same time.

Theoretically, setting all elements to mock.Anything to the argument matcher, then using .RunAndReturn has the effect of a totally type-safe expectation. This is kind of the style of matryer/moq, just done in a different way.

It's for sure a hard thing to categorize correctly :D

Hi, thanks for this table, it is quite helpful.

There is another, quite new, mocking library that I've been evaluating for our projects that is quite promising too, in case you want to consider it: https://github.com/ovechkin-dm/mockio

It is still not well known, but what I've tested so far works fine and the fact that it does not require mock generation is quite helpful.

It’s strange that it’s still not in the table. great library without code generation

@m1khal3v @Zurvarian I've added mockio to the table

Hi, thanks for your great comparison.

Just a small correction: minimock has a "Capturer" capability. All call parameters are stored in a mock and may be accessed later via Calls() function.

@mbalabin good catch, thanks! Actually, all libs but gomock allow introspecting calls afterward. IMO, mockio provides the best API for that, but I've updated the table accordingly.

@m1khal3v @Zurvarian I've added mockio to the table

Thank you for adding mockio to your table.
The feature set for it is very accurate.