MattiSG/Watai

var promises = require('q');


/**@class    A matcher that tests its element against a user-provided function.
*@extends    matchers.AbstractMatcher
*@memberOf    matchers
*/
var FunctionMatcher = new Class( /** @lends matchers.FunctionMatcher# */ {
    Extends: require('./AbstractMatcher'),

    type: 'function',

    onElementFound: function(element) {
        this.compare(element);
    },

    compare: function compare(element) {
        promises.fcall(this.expected, element)
                .done(this.succeed, this.fail);
    },

    formatFailure: function formatFailure(actual) {
        return this.selector
                + ' had its testing function fail, saying "' + actual + '":\n'
                + this.expected;
    },

    toString: function toString() {
        return 'Evaluation of ' + (this.expected.name || 'an unnamed function') + ' on ' + this.selector;
    }
});

module.exports = FunctionMatcher;    // CommonJS export