jasmine_customMatcher_test.js

var customMatchers = {
  toStartWith: function (util, customEqualityTesters) {
    return {
      compare: function (actual, expected) {
        return { pass: actual.slice (0, expected.length) === expected };
      }
    };
  }
};

describe ('test', function () {
  it ('test 1', function () {
    // it() 単位でのみ有効
    jasmine.addMatchers (customMatchers);

    expect ('foobar').toStartWith ('foo');
    expect ('abc').not.toStartWith ('foo');
  });

  xit ('test 2', function () {
    // ここではカスタムマッチャーが登録されてないのでエラーになる
    expect ('foobar').toStartWith ('foo');
    expect ('abc').not.toStartWith ('foo');
  });
});