Global Fixtures

Global Teardown Fixtures

The Global Teardown fixture shuts down the server created by the global setup fixture for the testing. To use the teardown fixture, we have to export it from the script file first. 

exports.mochaGlobalTeardown = async function () {
  await this.server.stop();
  console.log('server stopped!');
};

We can access the server created in the setup fixture using this.server and shut it down using the stop() method. This prints a message “Server stopped” to the console.

You can use Global fixtures only when you want to run them once and do not want to share the state with tests. If you want to access an in-memory value, you cannot use the global fixtures directly. Instead, we can create the fixtures to start and stop the server and then connect it to a server in your tests. 

let server;
export const mochaGlobalSetup = async () => {
  server = await startServer({port: process.env.TEST_PORT});
  console.log(`server running on port ${server.port}`);
};

export const mochaGlobalTeardown = async () => {
  await server.stop();
  console.log('server stopped!');
};

This program starts and stops the server as we discussed before in this article. 

import {connect} from 'my-server-connector-thingy';
describe('my API', function () {
  let connection;
  before(async function () {
    connection = await connect({port: process.env.TEST_PORT});
  });
  it('API', function () {
    // write tests here
  });

  after(async function () {
    return connection.close();
  });
});

We imported "connect" from the server library to connect to the server of the test port and then execute your tests using the it() method to execute them individually. After the tests are performed, the server can be closed using the after() and connection.close() methods.

FAQs

1. What are global fixtures?
   This global initialization and clean-up after and before running the tests to start and stop the servers are called global fixtures. The global fixture methods are monitored by an execution monitor, which makes error handling and reporting easier than initialization functions. 
    
2. What does a global setup fixture do?
   Global setup fixtures run before you run your tests and start a server required to run your tests using a specified port. The server created by this fixture runs until you shut it down.
    
3. What does a global teardown fixture do?
   The Global Teardown fixture shuts down the server created by the global setup fixture for the testing after all the tests are run individually or as a group. 
    
4. Is the export function async?
   The export function used to export the global fixtures can either be async or not async. It depends on the code of tests we want to run.
    
5. When do we use global fixtures?
   We use global fixtures for spinning servers, creating resources for tests, creating sockets or schedulers, etc.

Key Takeaways

We have discussed global fixtures in Mocha, Global Setup, and Teardown. The global fixtures are used to start and clean up before and after a test is executed. We also discussed how to use global fixtures in different cases.

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