LambdaAPI provides an interface to enable mocking the lambda.Lambda service client's API operation, paginators, and waiters. This make unit testing your code that calls out to the SDK's service client's calls easier.

The best way to use this interface is so the SDK's service client's calls can be stubbed out for unit testing your code with the SDK without needing to inject custom request handlers into the the SDK's request pipeline.

// myFunc uses an SDK service client to make a request to
// AWS Lambda.
func myFunc(svc lambdaiface.LambdaAPI) bool {
    // Make svc.AddPermission request

func main() {
    sess := session.New()
    svc := lambda.New(sess)


In your _test.go file:

// Define a mock struct to be used in your unit tests of myFunc.
type mockLambdaClient struct {
func (m *mockLambdaClient) AddPermission(input *lambda.AddPermissionInput) (*lambda.AddPermissionOutput, error) {
    // mock response/functionality

TestMyFunc(t *testing.T) {
    // Setup Test
    mockSvc := &mockLambdaClient{}


    // Verify myFunc's functionality

It is important to note that this interface will have breaking changes when the service model is updated and adds new API operations, paginators, and waiters. Its suggested to use the pattern above for testing, or using tooling to generate mocks to satisfy the interfaces.

LambdaAPI is referenced in 2 repositories