costexploreriface package – github.com/aws/aws-sdk-go-v2/service/costexplorer/costexploreriface – Go Packages

ClientAPI provides an interface to enable mocking the
costexplorer.Client methods. 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 SDK’s request pipeline.

// myFunc uses an SDK service client to make a request to
// AWS Cost Explorer.
func myFunc(svc costexploreriface.ClientAPI) bool {
    // Make svc.CreateCostCategoryDefinition request
}

func main() {
    cfg, err := external.LoadDefaultAWSConfig()
    if err != nil {
        panic("failed to load config, " + err.Error())
    }

    svc := costexplorer.New(cfg)

    myFunc(svc)
}

In your _test.go file:

// Define a mock struct to be used in your unit tests of myFunc.
type mockClientClient struct {
    costexploreriface.ClientPI
}
func (m *mockClientClient) CreateCostCategoryDefinition(input *costexplorer.CreateCostCategoryDefinitionInput) (*costexplorer.CreateCostCategoryDefinitionOutput, error) {
    // mock response/functionality
}

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

    myfunc(mockSvc)

    // 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.