An Asp.Net MVC PartialView for in-browser page testing. Makes it possible to test complex UIs and widgets 'in situ' but with zero client-side pageweight in production.

QUnitTestIf.cshtml

@model IEnumerable<string>
@if (Request.IsLocal 
    && ( Request.QueryString["test"]!=null 
        || 
        Request.QueryString.ToString().Split('&').Any(k=>k.Equals("test",StringComparison.InvariantCultureIgnoreCase))
))
{
    <div id="unit-tests">
    
    <script src='~/scripts/qunit-1.20.0.js'></script>
    <script src='~/scripts/qunit-parameterize.js'></script>
    <div>
        <h1 id="qunit-header">Run All QUnit Tests</h1>
        <h2 id="qunit-banner"></h2>
        <div id="qunit-testrunner-toolbar"></div>
        <h2 id="qunit-userAgent"></h2>
        <ol id="qunit-tests"></ol>
        <div id="qunit-fixture">test markup, will be hidden</div>
    </div>
    @foreach (var testHelpers in new []{"~/scripts/tests/test-helpers.js"})
    {
        <script src="@Url.Content(testHelpers)"></script>
    }
    @foreach (var testScriptPath in Model??new string[0])
    {
        <script src="@Url.Content(testScriptPath)"></script>
    }
    <script>QUnit.done(function () { $('html, body').animate({ scrollTop: $("#unit-tests").offset().top-30 }, { easing: 'swing' }); })</script>

    <style scoped>div#unit-tests {margin: 30px 0;clear: both;display: block;}</style>
    <style scoped>
/* cut-n-paste from qunit.css but some changes to combat page styles affecting test layout*/
/*!
 * QUnit 1.20.0
 * http://qunitjs.com/
 *
 * Copyright jQuery Foundation and other contributors
 * Released under the MIT license
 * http://jquery.org/license
 *
 * Date: 2015-10-27T17:53Z
 */

/** Font Family and Sizes */

         #qunit-tests, #qunit-header, #qunit-banner, #qunit-testrunner-toolbar, #qunit-filteredTest, #qunit-userAgent, #qunit-testresult {
             font-family: "Helvetica Neue Light", "HelveticaNeue-Light", "Helvetica Neue", Calibri, Helvetica, Arial, sans-serif !important;
         }

        #qunit-testrunner-toolbar, #qunit-filteredTest, #qunit-userAgent, #qunit-testresult, #qunit-tests li { font-size: small !important}
        #qunit-tests { font-size: smaller !important; }


        /** Resets */

        #qunit-tests, #qunit-header, #qunit-banner, #qunit-filteredTest, #qunit-userAgent, #qunit-testresult, #qunit-modulefilter {
            margin: 0;
            padding: 0;
        }


        /** Header */

        #qunit-header {
            padding: 0.5em 0 0.5em 1em;

            color: #8699A4;
            background-color: #0D3349;

            font-size: 1.5em;
            line-height: 1em;
            font-weight: 400;

            border-radius: 5px 5px 0 0;
        }

        #qunit-header a {
            text-decoration: none;
            color: #C2CCD1;
        }

        #qunit-header a:hover,
        #qunit-header a:focus {
            color: #FFF;
        }

        #qunit-testrunner-toolbar label {
            display: inline-block;
            padding: 0 0.5em 0 0.1em;
        }

        #qunit-banner {
            height: 0.7em;
        }

        #qunit-testrunner-toolbar {
            padding: 0.5em 1em 0.5em 1em;
            color: #5E740B;
            background-color: #EEE;
            overflow: hidden;
        }

        #qunit-filteredTest {
            padding: 0.5em 1em 0.5em 1em;
            background-color: #F4FF77;
            color: #366097;
        }

        #qunit-userAgent {
            padding: 0.5em 1em 0.5em 1em;
            background-color: #2B81AF;
            color: #FFF;
            text-shadow: rgba(0, 0, 0, 0.5) 2px 2px 1px;
        }

        #qunit-modulefilter-container {
            float: right;
            padding: 0.2em;
        }

        .qunit-url-config {
            display: inline-block;
            padding: 0.1em;
        }

        .qunit-filter {
            display: block;
            float: right;
            margin-left: 1em;
        }

        /** Tests: Pass/Fail */

        #qunit-tests {
            list-style-position: inside;
        }

        #qunit-tests li {
            padding: 0.4em 1em 0.4em 1em;
            border-bottom: 1px solid #FFF;
            list-style-position: inside;
        }

        #qunit-tests > li {
            display: none;
        }

        #qunit-tests li.running,
        #qunit-tests li.pass,
        #qunit-tests li.fail,
        #qunit-tests li.skipped {
            display: list-item;
        }

        #qunit-tests.hidepass li.running,
        #qunit-tests.hidepass li.pass {
            visibility: hidden;
            position: absolute;
            width: 0;
            height: 0;
            padding: 0;
            border: 0;
            margin: 0;
        }

        #qunit-tests li strong {
            cursor: pointer;
            font-size: inherit;
            font-weight: inherit;
            line-height: inherit;
            display: initial;
        }

        #qunit-tests li.skipped strong {
            cursor: default;
        }

        #qunit-tests li a {
            padding: 0.5em;
            color: #C2CCD1;
            text-decoration: none;
        }

        #qunit-tests li p a {
            padding: 0.25em;
            color: #6B6464;
        }
        #qunit-tests li a:hover,
        #qunit-tests li a:focus {
            color: #000;
        }

        #qunit-tests li .runtime {
            float: right;
            font-size: smaller;
        }

        .qunit-assert-list {
            margin-top: 0.5em;
            padding: 0.5em;

            background-color: #FFF;

            border-radius: 5px;
        }

        .qunit-source {
            margin: 0.6em 0 0.3em;
        }

        .qunit-collapsed {
            display: none;
        }

        #qunit-tests table {
            border-collapse: collapse;
            margin-top: 0.2em;
        }

        #qunit-tests th {
            text-align: right;
            vertical-align: top;
            padding: 0 0.5em 0 0;
            font-size: inherit;
            border: 1px solid #ccc;
        }

        #qunit-tests td {
            vertical-align: top;
            font-size: inherit;
            font-family: 'consolas','monospace'
        }

        #qunit-tests pre {
            margin: 0;
            white-space: pre-wrap;
            word-wrap: break-word;
        }

        #qunit-tests del {
            background-color: #E0F2BE;
            color: #374E0C;
            text-decoration: none;
        }

        #qunit-tests ins {
            background-color: #FFCACA;
            color: #500;
            text-decoration: none;
        }

        /*** Test Counts */

        #qunit-tests b.counts { color: #000; }
        #qunit-tests b.passed { color: #5E740B; }
        #qunit-tests b.failed { color: #710909; }

        #qunit-tests li li {
            padding: 5px;
            background-color: #FFF;
            border-bottom: none;
            list-style-position: inside;
        }

        /*** Passing Styles */

        #qunit-tests li li.pass {
            color: #3C510C;
            background-color: #FFF;
            border-left: 10px solid #90FF90;
        }

        #qunit-tests .pass {color: #528CE0;background-color: #D2E0E6; }
        #qunit-tests .pass .test-name { color: #366097; }

        #qunit-tests .pass .test-actual,
        #qunit-tests .pass .test-expected { color: #999; }

        #qunit-banner.qunit-pass { background-color: #90FF90;}

        /*** Failing Styles */

        #qunit-tests li li.fail {
            color: #710909;
            background-color: #FFF;
            border-left: 10px solid #EE5757;
            white-space: pre;
        }

        #qunit-tests > li:last-child {
            border-radius: 0 0 5px 5px;
        }

        #qunit-tests .fail {color: #000;background-color: #EE5757; }
        #qunit-tests .fail .test-name,
        #qunit-tests .fail .module-name { color: #000; }

        #qunit-tests .fail .test-actual { color: #EE5757; }
        #qunit-tests .fail .test-expected { color: #008000; }

        #qunit-banner.qunit-fail { background-color: #EE5757; }

        /*** Skipped tests */

        #qunit-tests .skipped {
            background-color: #EBECE9;
        }

        #qunit-tests .qunit-skipped-label {
            background-color: #F4FF77;
            display: inline-block;
            font-style: normal;
            color: #366097;
            line-height: 1.8em;
            padding: 0 0.5em;
            margin: -0.4em 0.4em -0.4em 0;
        }

        /** Result */

        #qunit-testresult {
            padding: 0.5em 1em 0.5em 1em;

            color: #2B81AF;
            background-color: #D2E0E6;

            border-bottom: 1px solid #FFF;
        }
        #qunit-testresult .module-name {
            font-weight: 700;
        }

        /** Fixture */

        #qunit-fixture {
            position: absolute;
            top: -10000px;
            left: -10000px;
            width: 1000px;
            height: 1000px;
        }
    </style>
    <!-- End Unit Tests ========================================================================== -->
    </div>
}

Usage

@Html.Partial("QUnitTestIf.cshtml", new []{"~/scripts/tests/testfile1.js", "~/scripts/tests/testfile2.js" /*, ...etc...*/ })

If the partial view is called in production or test or anywhere except locally, nothing will be rendered.
Only when served to localhost, unit tests will run if you include &test= in the querystring.

Dependencies

<script src='~/scripts/qunit-1.20.0.js'></script>
Although you'll notice that I also use <script src='~/scripts/qunit-parameterize.js'></script>