How to use assertthat - 10 common examples

const validate = async function ({ directory, repository }) {
  /* eslint-disable global-require */
  const packageJson = require(path.join(directory, 'package.json'));
  /* eslint-enable global-require */

  assert.that(packageJson.version).is.equalTo('1.0.0');

  const listTags = shell.ls(`${repository}/refs/tags`);

  const tags = listTags.stdout.split('\n');

  assert.that(tags[0]).is.equalTo('1.0.0');
};

test('has configure and getLogger functions.', async (): Promise => {
    /* eslint-disable @typescript-eslint/unbound-method */
    assert.that(flaschenpost.configure).is.ofType('function');
    assert.that(flaschenpost.getLogger).is.ofType('function');
    /* eslint-enable @typescript-eslint/unbound-method */
  });

test('has configure and getLogger functions.', async (): Promise => {
    /* eslint-disable @typescript-eslint/unbound-method */
    assert.that(flaschenpost.configure).is.ofType('function');
    assert.that(flaschenpost.getLogger).is.ofType('function');
    /* eslint-enable @typescript-eslint/unbound-method */
  });

const constraint = `>=${latestVersion} <${semver.inc(latestVersion, 'major')}`;

  /* eslint-disable global-require */
  const packageJson = await fs.readFile(path.join(directory, 'package.json'), { encoding: 'utf-8' });
  /* eslint-enable global-require */

  const newPackageJson = stripIndent`
  {
    "name": "test-package",
    "version": "0.0.1",
    "engines": {
      "node": "${constraint}"
    }
  }`;

  assert.that(packageJson).is.atLeast(`${newPackageJson}\n`);
};

const validate = async function ({ directory }) {
  /* eslint-disable global-require */
  const packageJson = require(path.join(directory, 'package.json'));
  /* eslint-enable global-require */

  assert.that(packageJson.version).is.equalTo('0.1.0');
};

test('sets itself as its successor if the successors list only has one element.', done => {
        peer.setSuccessor({ host: 'example.com', port: 3000 });
        peer.successors = [{ host: 'foo.com', port: 3000 }];

        peer.fixSuccessor();

        assert.that(peer.successor).is.equalTo(peer.self);
        done();
      });

test('initially contains information on the endpoint of the peer.', done => {
        assert.that(peer.predecessor).is.equalTo({
          host: 'localhost',
          port: 3000,
          id: sha1('localhost:3000')
        });
        done();
      });
    });

}, (code, stdout, stderr) => {
      assert.that(code).is.equalTo(0);

      const messages = stdout.split('\n').
        filter(line => line !== '').
        map(line => JSON.parse(line));

      assert.that(messages[0].level).is.equalTo('info');
      assert.that(messages[0].message).is.equalTo('Application started.');
      assert.that(messages[1].level).is.equalTo('error');
      assert.that(messages[1].message).is.equalTo('Something, somewhere went horribly wrong...');

      assert.that(stderr).is.equalTo('');
      done();
    });
  });

test('is a function.', done => {
    assert.that(handle).is.ofType('function');
    done();
  });

test('is an object.', done => {
    assert.that(p2p).is.ofType('object');
    done();
  });