JsHamcrest.Operators — Matcher Operators

Provides utilitary functions on top of matchers.

List Processing

JsHamcrest.Operators.filter(array, matcherOrValue)

Returns those items of array for which matcherOrValue matches:

var filtered = filter([0,1,2,3,4,5,6], even());
assertThat(filtered, equalTo([0,2,4,6]));

var filtered = filter([0,1,2,'1',0], 1);
assertThat(filtered, equalTo([1,'1']));

Parameters:

• array – Array of items to be filtered.
• matcherOrValue – Instance of JsHamcrest.SimpleMatcher or a value.

Returns:

Filtered array.

Unit Testing

JsHamcrest.Operators.assert(actualValue, matcherOrValue[, {fail, pass, message}])

Generic assert function to be used for easy integration with testing frameworks. Usage example:

// Add the following method to your testing framework...

function iAssertThat(actualValue, matcherOrValue, message) {
    return JsHamcrest.Operators.assert(actualValue, matcherOrValue, {
        message: message,
        fail: function(failMessage) {
            // Forward the call to the appropriate method provided by the testing framework
            myTestingFramework.fail(failMessage);
        },
        pass: function(passMessage) {
            // Forward the call to the appropriate method provided by the testing framework
            myTestingFramework.pass(passMessage);
        }
    });
}

// ...and then you'll be able to leverage the power of JsHamcrest in your test cases
result = iAssertThat(50, between(0).and(100));

result.passed // Output: true
result.get()  // Output: "50 between 0 and 100: Success"

Parameters:

• actualValue – Actual value.
• matcherOrValue – Instance of JsHamcrest.SimpleMatcher or a value.
• fail – (Optional) Callback function to be called when actualValue doesn’t match matcherOrValue.
• pass – (Optional) Callback function to be called when actualValue does match matcherOrValue.
• message – (Optional) Text that describes the assertion on an even higher level.

Returns:

Instance of JsHamcrest.Description with the assertion description. Also, the result of the assertion (success or failure/error) can be accessed through the passed attribute.

JsHamcrest.Operators.callTo(func[, arg...])

Returns a zero-args function that calls the function func with the given args:

var func = callTo(parseInt, "2");
assertThat(func(), sameAs(2));

This is specially useful when used along with JsHamcrest.Matchers.raises() or JsHamcrest.Matchers.raisesAnything():

assertThat(callTo(myFunc, arg1, arg2), raisesAnything());

Parameters:

• func – Function to delegate calls to.
• arg – Optional arguments to func.

Returns:

Function that delegates calls to func.

See also

JsHamcrest API Reference