茉莉花角度指令测试

Question

我正在尝试测试Angular指令，该指令根据按键事件返回true或false。我在输入标记内有ng-model的UI中使用该指令。 HTML代码如下：

<div class="inline-middle-align set-margin ">
    <input class="form-control" type="text" ng-model="addedRP.Offset" min="0" max="999" maxlength="3" style="width: 65px" placeholder="Offset" rp-Offset-Input-Validation-Directive required/>
</div>

指令代码是：

angular.module('helperModule')
.directive('rpOffsetInputValidationDirective', function (e) {
    'use strict';
    return {
        require: 'ngModel',
        link: function (scope, elem) {

            elem.on('keypress', function (e) {
                if (e.which !== 8 && e.which !== 0 && (e.which < 48 || e.which > 57)) {
                    return false;
                }
            });
        }
    };
});

我已经为它编写了一个测试，但它没有用。

it('should return true called on a keypress', function () {
    $rootScope.happy = 10;              
    var ele = angular.element("<input ng-model='happy' rp-offset-input-validation-directive/>");
    element = $compile(ele)($rootScope);
    $rootScope.$digest();
    $rootScope.e = $.Event('keypress');
    e.which = 50;
    $(ele[0]).trigger(e);
    expect($rootScope.happy).toBe(2);
});