How to Mock out AWS SDK for Go call

Question

I am writing a unit test for a function that uses the AWS SDK for Go to get a secret from the AWS Secrets Manager:

main.go

//Helper function to get secret from AWS Secret Manager
func getAWSSecrets(svc secretsmanageriface.SecretsManagerAPI) (secretMap map[string]string, err error) {
    //Get secret config values
    req, resp := svc.GetSecretValueRequest(&secretsmanager.GetSecretValueInput{
        SecretId: aws.String("my/secret/string"),
    })

    err = req.Send()
    if err != nil {
        return nil, err
    }

 ...
}

In order to test this, I need to create a mock AWS Secret Manager Client. I've set up the basic skeleton of how that will work:

main_test.go

type MockSecretsManagerClient struct {
  secretsmanageriface.SecretsManagerAPI
} 

func (m *MockSecretsManagerClient) GetSecretValueRequest(input *secretsmanager.GetSecretValueInput) (req *request.Request, resp *secretsmanager.GetSecretValueOutput){
  // Confused on how to mock out the returned `req`
}


// tests getAWSSecrets
func (suite *ServerTestSuite) TestGetAWSSecrets() {
    //Setup test 
  mockSvc := &MockSecretsManagerClient{}
  req, resp := getAWSSecrets(mockSvc)
}

I'm running into trouble trying to mock the returned request from GetSecretValueRequest. Furthermore, once I mock this request, I'm not sure how to handle mocking req.Send(). Is there a simple way to do this? Or are there any good examples of someone doing this?

Answer 1

First, find the service in the "AWS SDK for Go API Reference."

Then look up the API call. Your call is here https://docs.aws.amazon.com/sdk-for-go/api/service/secretsmanager/#SecretsManager.GetSecretValueRequest

The prototype for the API call is

func (c *SecretsManager) GetSecretValueRequest(input *GetSecretValueInput) (req *request.Request, output *GetSecretValueOutput)

So it returns a request.Request and a GetSecretValueOutput

The two output items are structs and they are linked in the documentation. The mock should return those two items in the same way ie

func (m *MockSecretsManagerClient) GetSecretValueRequest(input *secretsmanager.GetSecretValueInput) (req *request.Request, resp *secretsmanager.GetSecretValueOutput) {

    req = new(request.Request)
    r := new(http.Response)
    r.Status = "200 OK"
    r.Status = 200
    req.HTTPRequest = r
    resp.SecretString = new(String("this is the dummy value"))

    return
}

If you need the mock values to be mock like "real" data from a live API service then write a quick program to do a call and Printf the return values using "%#v" format. This should give you most of what you need