Matchers: Core

allOf matches if an item matches all of the given Matchers.

  assertThat("good", allOf(equalTo("good"), not(equalTo("bad"))));

anyOf matches if the item being matched matches any of the given Matchers.

  assertThat("good", anyOf(equalTo("bad"), equalTo("good")));

anything always matches.

  assertThat("the great void", anything());

both, and either create a CombinableMatcher, useful for chaining matchers together for readability.

  assertThat("good", both(equalTo("good")).and(not(equalTo("bad"));
  assertThat("good", either(equalTo("good")).or(not(equalTo("bad"));

describedAs wraps another Matcher to return a modified description.

  assertThat(3, describedAs("%0 is a magic number", equalTo(3), 3);

isA matches if the item is an instance of the given type.

  assertThat("waffles", isA(String));

not inverts the result of another Matcher or value.

  assertThat(3, not(4));

throws matches if the item under test is a Function, and throws an Error matching the given Matcher.

  assertThat(function():void {
      systemUnderTest.methodCall(given, bad, args);
    }, 
    throws( 
      allOf(
        instanceOf(OhNoItsAnError),
        hasPropertyValue("message", "oh no"))));