Getting Started with Testing with Jasmine

Testing is an important part of JavaScript.

In this article, we’ll look at getting started with Jasmine.

Using Jasmine with Node

We can add Jasmine to our Node project by running:

npm install --save-dev jasmine

This will install a local copy of Jasmine for our project.

We can also install it globally by running:

npm install -g jasmine

Then we can initialize the Jasmine project by running:

jasmine init

if we installed Jasmine globally.

If we didn’t we run:

npx jasmine init

Then we generate the spec and source files by running:

jasmine examples

Then we can change the configuration in spec/support/jasmine.json /

The spec_dir property is the directory with the test files.

spec_file has the patterns for the spec files.

helpers have the paths for the helpers for the test files.

stopSpecOnExpectationFailure is a boolean that indicates whether we want to stop running tests when a test fails.

random means whether we run specs in a semi-random order.

We can run tests with:

jasmine spec/appSpec.js

where spec/appSpec.js is the path.

We can also specify a pattern for the path of the tests;

jasmine "**/tests/**/*Spec.js"

CLI Options

We can change the options by setting some config.

For instance, we can write:

JASMINE_CONFIG_PATH=spec/config/jasmine.json jasmine

jasmine --config=spec/config/jasmine.json

We can disable colors with the --no-color flag.

--filter lets us specs that match a given string.

--stop-on-failure lets us stop running tests on first failure if it’s true .

--random tells Jasmine to run tests in semi-random order.

--seed lets us set the randomization seed if randomization is turned on.

--reporter lets us set the test reporter.

We can also use the jasmine library to set the config.

For instance, we can write:

const Jasmine = require('jasmine');
const jasmine = new Jasmine();
jasmine.loadConfigFile('spec/support/jasmine.json');
jasmine.loadConfig({
  spec_dir: 'spec',
  spec_files: [
    'appSpec.js',
    'requests/**/*[sS]pec.js',
    'utils/**/*[sS]pec.js'
  ],
  helpers: [
    'helpers/**/*.js'
  ]
});

to set the config.

We can also set our own onComplete callback to do what we want is all tests pass or when they fail:

jasmine.onComplete(function(passed) {
  if (passed) {
    console.log('passed');
  } else {
    console.log('failed');
  }
});

Reporters

We can set the test reports.

The default is the ConsoleReporter.

We can set the reporter by writing:

jasmine.configureDefaultReporter({
  timer: new jasmine.jasmine.Timer(),
  print(...args) {
    process.stdout.write(args);
  },
  showColors: true
});

to change how test results are reported.

Run Tests

To run tests, we run the execute method:

jasmine.execute();

We can also pass in a file name or spec name to run them:

jasmine.execute(['fooSpec.js'], 'a spec name');

So we can write:

const Jasmine = require('jasmine');
const jasmine = new Jasmine();

jasmine.loadConfigFile('spec/support/jasmine.json');
jasmine.configureDefaultReporter({
  showColors: false
});
jasmine.execute();

to run our tests.

Conclusion

We can use Jasmine to run our tests.

There’re many options we can set, like the files to run, whether to show colors or not, randomize tests, etc.