MIGRATION__18_0_0.md

Migration of jasmine to jest

This release has removed the previous unit testing approach using karma as test runner and jasmine as testing framework in favor of jest for both. Most of the required migration stuff - including a tool for automatic migration - is listed in the official migration guide: https://facebook.github.io/jest/docs/en/migration-guide.html It is strongly recommended to use this tool the automatically migrate your existing unit tests.

Most code is similar or equivalent to jasmine. In case the automatic tool does not or only partially works, you will find a (non-exhaustive) list of statements to replace below.

jasmine	jest	Notes
jasmine.addMatchers	expect.extend
jasmine.createSpy	jest.fn	Spies cannot be named in jest.
jasmine.createSpyObj	./.	There is no counterpart for this in jest. You will have to create your own helper function.
jasmine.any	expect.any
jasmine.objectContaining	expect.objectContaining

Helper function as replacement suggestion for jasmine.createSpyObj:

export default function createSpyObj<T>(...names: string[]): T {
  const result = {};
  names.forEach(n => (result[n] = jest.fn()));

  return (result as any) as T;
}

Note that it does not take a name for the spy object as its first parameter, since spies cannot be named.

As general rules:

• The test structure itself does not differ from the jasmine version.
• Most helper functions included in the jasmine.* namespace before are now contained in extend.*.
• Spies and every utility linked to them are included in the jest.* namespace.

In case you are facing any errors or problems - especially with DOM-heavy libraries in use - see the - troubleshooting guide.