Tag: testing

Example of Apex HttpCalloutMock

September 21st, 2023
Reading Time: 2 minutes
In Apex, you can use the HttpCalloutMock interface to mock HTTP callouts when writing unit tests for code that makes HTTP requests. This allows you to control the responses returned by the mock instead of making actual HTTP requests during testing. Here’s an example of how to use HttpCalloutMock in Apex:

Let’s say you have a class that makes an HTTP callout to an external service, and you want to write a unit test for it. First, you need to create a mock class that implements the HttpCalloutMock interface. This mock class will simulate the HTTP response you expect:
```
@IsTest
public class MyHttpCalloutMock implements HttpCalloutMock {
    // Implement the respond method to simulate the HTTP response.
    public HTTPResponse respond(HTTPRequest request) {
        // Create a new HTTPResponse object to mock the response.
        HTTPResponse response = new HTTPResponse();
        response.setHeader('Content-Type', 'application/json');
        response.setBody('{"message": "Mocked response"}');
        response.setStatusCode(200);

        return response;
    }
}
```
In this example, MyHttpCalloutMock implements the HttpCalloutMock interface and provides a mock response with a JSON body and a 200 status code.

Now, you can use this mock class in your unit test to simulate the HTTP callout:
```
@IsTest
public class MyHttpCalloutTest {
    @isTest static void testHttpCallout() {
        // Create an instance of the HttpCalloutMock class.
        HttpCalloutMock mock = new MyHttpCalloutMock();

        // Set the mock in the test context.
        Test.setMock(HttpCalloutMock.class, mock);

        // Call your code that makes the HTTP callout.
        // Replace this with the actual call to your HTTP request method.
        String response = MyHttpCalloutClass.makeHttpCallout();

        // Perform assertions on the response.
        System.assertEquals('{"message": "Mocked response"}', response);
    }
}
```
In the testHttpCallout method, we set the MyHttpCalloutMock as the mock for HTTP callouts using Test.setMock(). Then, we call the code that makes the HTTP callout, which will now use the mock response provided by MyHttpCalloutMock. Finally, we assert that the response matches the expected value.

This way, you can write unit tests for code that makes HTTP callouts without actually making external requests, ensuring predictable and controlled testing conditions.
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How to mock callouts in Salesforce Apex

September 20th, 2023
Reading Time: 2 minutes
No, you cannot make any callouts in Apex unit tests. Even if one day is possible, it is generally recommended to avoid making actual callouts to external services during unit testing. Instead, you should mock the callouts to ensure isolation, control, efficiency, and determinism in your tests.

Mocking callouts means simulating the responses you expect from the callouts without actually making the network requests. This approach helps you maintain consistent test results and reduces the reliance on external services during testing.

Mocking callouts in Apex is important for several reasons:
1. Isolation: By mocking callouts, you can isolate your Apex code from external dependencies. This means that your tests will not rely on external services or APIs, ensuring that they can be executed consistently, regardless of the availability or stability of those external services.
2. Control: Mocking allows you to have complete control over the responses received from the callouts. You can simulate different scenarios and responses, such as successful responses, error responses, or even timeouts, to thoroughly test how your code handles different situations.
3. Efficiency: Avoiding actual callouts during testing improves the efficiency of your test suite. Callouts involve network requests, which can be time-consuming and add unnecessary overhead to your tests. Mocking allows your tests to run faster since the responses are generated locally without the need for network communication.
4. Deterministic Testing: Mocking enables you to have predictable and deterministic tests. By defining the exact responses your code will receive, you can ensure consistent test results every time you run your tests, regardless of external factors.
5. Error Handling: Mocking callouts allows you to easily test and verify how your code handles various error scenarios. You can simulate different error conditions and ensure that your code behaves correctly by handling the errors and executing the appropriate error-handling logic.
Overall, mocking callouts in Apex provides a controlled and efficient way to test your code, helping you identify and fix issues early on, while ensuring the reliability and stability of your application.

To mock callouts in Apex unit tests, you can use the built-in Apex mocking framework. By implementing the HttpCalloutMock interface and defining the desired response in the respond method, you can simulate callout responses.

Here’s an example to illustrate the process:
```
@isTest
public class MockCallout implements HttpCalloutMock {
    public HttpResponse respond(HttpRequest req) {
        // Create and return the desired response data
        HttpResponse res = new HttpResponse();
        res.setHeader('Content-Type', 'application/json');
        res.setBody('{"example": "mock response"}');
        res.setStatusCode(200);
        return res;
    }
}

@isTest
public class MyCalloutClassTest {
    @isTest
    static void testCallout() {
        // Set the mock callout
        Test.setMock(HttpCalloutMock.class, new MockCallout());
        
        // Start test context
        Test.startTest();
        
        // Call the method that makes the callout
        MyCalloutClass myClass = new MyCalloutClass();
        myClass.makeCallout();
        
        // Stop test context
        Test.stopTest();
        
        // Assert the results
        // ...
    }
}
```
In this example, the MockCallout class implements the HttpCalloutMock interface to simulate the expected response. The MyCalloutClassTest test class sets the mock callout using Test.setMock and then calls the method that makes the callout. This enables you to test the behavior of your code without actually making the callout.

By following this approach, you can effectively mock callouts and perform thorough testing of your Apex code while maintaining control, efficiency, and deterministic results.
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How to Mock Axios with Jest

March 28th, 2023
Reading Time: < 1 minutes
Axios is a popular JavaScript library used for making HTTP requests in web applications. Jest, on the other hand, is a JavaScript testing framework that comes with a built-in mocking feature that makes it easy to mock Axios in your tests. In this blog post, we’ll explore how to mock Axios with Jest, step by step.

To mock Axios with Jest, you can use the Jest mock function to replace the actual Axios library with a mock implementation.

Here is an example of how to mock Axios with Jest:
```
// Import the Axios library
import axios from 'axios';

// Mock the Axios library with Jest
jest.mock('axios');

// Define the mock response data
const mockResponse = {
  data: {
    id: 1,
    name: 'John Doe',
  },
};

// Set up the mock implementation for Axios
axios.get.mockImplementation(() => Promise.resolve(mockResponse));

// Call the Axios method in your test
axios.get('/users/1').then((response) => {
  expect(response.data).toEqual(mockResponse.data);
});
```
In the example above, we first import the Axios library and then mock it with Jest. We then define a mock response data object and set up the mock implementation for the Axios get method to return a Promise that resolves with the mock response data.

Finally, we call the Axios get method in our test and use Jest’s expect function to assert that the response data matches the mock response data.

Note that you may need to modify this example to suit your specific use case, depending on the methods you are calling and the data you are expecting in response.
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Mock AWS SDK with Jest in TypeScript

January 29th, 2023
Reading Time: 2 minutes

The AWS SDK is an incredibly powerful tool for managing resources in the cloud. But what if you want to use the SDK without having to deploy your code to AWS?

Mocking the SDK with Jest and TypeScript is a great way to quickly and easily test code that interacts with AWS services. By mocking the SDK, you can simulate requests and responses to ensure that everything works as expected.

This tutorial will walk you through how to create a mock of the AWS SDK and how to use it with Jest and TypeScript

When writing automated tests for applications that use Amazon Web Services (AWS) APIs, it can be difficult to test code that interacts with the AWS SDK. In order to make testing easier, you can use Jest in combination with TypeScript to mock the AWS SDK and simulate responses from the AWS service. This makes it possible to create reliable tests for your application without actually calling AWS APIs.

Advantages of mocking the AWS SDK
- Avoid hitting AWS services will make you save so much money, especially if you have thousands of tests. Even if you use Localstack, your project’s configuration from checking out the code until you run it will take more time.
- You tests will run faster
Disadvantages of mocking the AWS SDK
- Slow down development process
- Mocks for almost every scenario, otherwis,e it will call the real code (what we want to avoid)
Let’s see an example of how to mock the AWS SDK with Jest and TypeScript

The following code mocks two methods of SQS: receiveMessage and deleteMessage. If your code uses more methods of the AWS SDK you will have to mock all of them. Otherwise, your tests will call the real code.
```
import AWS from "aws-sdk";
jest.mock("aws-sdk");
const mockAws = AWS as jest.Mocked;

const mySQSMock = {
  receiveMessage: () => {
    return {
      promise: () =>
        Promise.resolve({
          Messages: [{ Body: "test" }],
        }),
    };
  },
  deleteMessage: () => {
    return {
      promise: () => Promise.resolve(),
    };
  },
};

describe("My test suite", () => {
  beforeAll(() => {
    mockAws.SQS.mockImplementation(jest.fn().mockImplementation(() => mySQSMock));
  });

  test("My test", async () => {
    // TBD
  });
});
```
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Tag: testing

Example of Apex HttpCalloutMock

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How to mock callouts in Salesforce Apex

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How to Mock Axios with Jest

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Mock AWS SDK with Jest in TypeScript

Advantages of mocking the AWS SDK

Disadvantages of mocking the AWS SDK

Let’s see an example of how to mock the AWS SDK with Jest and TypeScript

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