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1 siliconforks 2 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
2     <html>
3     <head>
4     <title>JSCoverage user manual</title>
5     <link type="text/css" href="doc.css" rel="stylesheet">
6     </head>
7     <body>
8    
9     <h1>JSCoverage user manual</h1>
10    
11     <p>
12     JSCoverage is a tool used to measure code coverage in JavaScript
13     programs.
14     </p>
15    
16     <p>
17     JSCoverage has two components:
18     </p>
19    
20     <ol>
21     <li>An executable program which is used to add instrumentation to JavaScript code.
22     <li>A web application which is used to execute instrumented code and generate a
23     code coverage report.
24     </ol>
25    
26     <h2>Installing JSCoverage</h2>
27    
28     <p>
29     You can compile JSCoverage on GNU/Linux or Microsoft Windows, using GCC. On
30     Windows you will require <a href="http://cygwin.com/">Cygwin</a> or <a
31     href="http://mingw.org/">MinGW/MSYS</a>.
32     </p>
33    
34     <p>
35     You can extract and compile the code with the following commands:
36     </p>
37    
38     <pre>
39     tar jxvf jscoverage-0.1.tar.bz2
40     cd jscoverage-0.1
41     ./configure
42     make
43     </pre>
44    
45     <p>
46     This will create the <code>jscoverage</code> executable (<code>jscoverage.exe</code> on Windows).
47     You can install the executable in <code>/usr/local</code> with the command:
48     </p>
49    
50     <pre>
51     make install
52     </pre>
53    
54     <p>
55     Alternatively, since the program consists of only the single self-contained
56     <code>jscoverage</code> executable, you may simply copy it to a suitable location
57     in your <code>PATH</code>.
58     </p>
59    
60     <h2>Using JSCoverage</h2>
61    
62     <p>
63     Using JSCoverage requires three steps:
64     </p>
65    
66     <h3>1. Instrumenting code</h3>
67    
68     <p>
69     The first step is to add instrumentation to your JavaScript code. This is the function of the
70     <code>jscoverage</code> executable. You must provide two arguments:
71     </p>
72    
73     <pre>
74     jscoverage <var>SOURCE-DIRECTORY</var> <var>DESTINATION-DIRECTORY</var>
75     </pre>
76    
77     <p>
78     <var>SOURCE-DIRECTORY</var> is the directory containing the JavaScript code to be instrumented,
79     and <var>DESTINATION-DIRECTORY</var> is the name of the
80     directory to which <code>jscoverage</code> should output the instrumented code.
81     The <code>jscoverage</code> program will create <var>DESTINATION-DIRECTORY</var> if necessary and (recursively) copy
82     <var>SOURCE-DIRECTORY</var> to <var>DESTINATION-DIRECTORY</var>, instrumenting
83     any files ending with a <code>.js</code> extension.
84     </p>
85    
86     <p>
87     For example, if you have a file
88     <code><var>SOURCE-DIRECTORY</var>/dir/index.html</code> referencing the script
89     <code><var>SOURCE-DIRECTORY</var>/dir/script.js</code>, then
90     <code>jscoverage</code> will create a copy of the HTML file at
91     <code><var>DESTINATION-DIRECTORY</var>/dir/index.html</code> and an instrumented
92     version of the script at
93     <code><var>DESTINATION-DIRECTORY</var>/dir/script.js</code>.
94     </p>
95    
96     <table>
97     <tr>
98     <td><pre>
99     <var>SOURCE-DIRECTORY</var>/
100     dir/
101     index.html
102     script.js
103    
104     </pre></td>
105     <td class="arrow">&rarr;</td>
106     <td><pre>
107     <var>DESTINATION-DIRECTORY</var>/
108     dir/
109     index.html
110     script.js [instrumented]
111     jscoverage.html
112     </pre></td>
113     </tr>
114     </table>
115    
116     <p>
117     In addition, <code>jscoverage</code> creates a file called <code>jscoverage.html</code>
118     which is used to execute the instrumented code.
119     </p>
120    
121 siliconforks 14 <h3>2. Running instrumented code in the web application</h3>
122 siliconforks 2
123     <p>
124     Open <code>jscoverage.html</code> in your web browser.
125     The page contains a tabbed user interface:
126     </p>
127    
128     <ul>
129     <li>The "Browser" tab is used to display pages with instrumented scripts.
130     <li>The "Summary" tab is used to display code coverage data.
131     <li>The "Source" tab is used to display JavaScript code, showing the number of times
132     each line of code was executed.
133     <li>The "About" tab displays information about the current version of JSCoverage.
134     </ul>
135    
136     <img src="screenshot.png" alt="Screenshot">
137    
138     <p>
139     The "Browser" tab contains an <code>&lt;iframe&gt;</code>, which is initially empty.
140     You can load a page into this frame by
141     entering its URL into the "URL" input field. For example, to load
142     the file <code><var>DESTINATION-DIRECTORY</var>/dir/index.html</code>, you can
143     enter the relative URL <code>dir/index.html</code> into the input field.
144     </p>
145    
146     <h3>3. Generating the coverage report</h3>
147    
148     <p>
149     Once the JavaScript code in the page in the "Browser" tab has been executed, click on
150     the "Summary" tab. This will display the current code coverage statistics.
151     </p>
152    
153     <p>
154     As long as you do not reload the
155     <code>jscoverage.html</code> page, the coverage report statistics are
156     cumulative. If you execute more JavaScript in the frame in the "Browser" tab (e.g., by clicking on a link to
157     another scripted page, or by reloading the frame containing a scripted
158     page) and switch to the "Summary" tab again,
159     the coverage report will combine the statistics from the previous report with any newly generated statistics.
160     Reloading <code>jscoverage.html</code> resets all code coverage statistics to zero.
161     </p>
162    
163     <h2>Example</h2>
164    
165     <p>
166     The JSCoverage distribution comes with a trivial example program in the <code>doc/example</code> directory.
167     You can view the file <code>doc/example/index.html</code> in your web browser to run the (uninstrumented) program.
168     To instrument this program, follow these steps:
169     </p>
170    
171     <h3>1. Instrumenting code</h3>
172    
173     <p>
174     From the main distribution directory, execute the command:
175     </p>
176    
177     <pre>
178     jscoverage doc/example doc/instrumented
179     </pre>
180    
181     <p>
182     This will create the directory <code>doc/instrumented</code> and
183     place an instrumented copy of the code from <code>doc/example</code> in <code>doc/instrumented</code>.
184     </p>
185    
186     <h3>2. Executing instrumented code</h3>
187    
188     <p>
189     You can load the file <code>doc/instrumented/jscoverage.html</code> in your web browser and type
190     the URL for the instrumented code in the "URL" input field. Since a relative URL is accepted, you
191     can simply type <code>index.html</code> to load the page.
192     </p>
193    
194     <p>
195     Alternatively, you can append the URL to the query string of the
196     <code>jscoverage.html</code> URL; for example, if you are in the main JSCoverage
197     directory and the Firefox executable is in your <code>PATH</code>, you can load
198     the <code>jscoverage.html</code> frameset and the <code>index.html</code> page
199     all in one command line:
200     </p>
201    
202     <pre>
203     firefox "doc/instrumented/jscoverage.html?index.html"
204     </pre>
205    
206     <img src="screenshot2.png" alt="Screenshot">
207    
208     <p>
209     For this particular page, the JavaScript does not execute automatically:
210     you have to select one of the radio buttons to execute the code.
211     </p>
212    
213     <img src="screenshot3.png" alt="Screenshot">
214    
215     <h3>3. Generating the coverage report</h3>
216    
217     <p>
218 siliconforks 14 Once you have executed the JavaScript code, you are instructed to click on the
219 siliconforks 2 "Summary" tab.
220     </p>
221    
222     <img src="screenshot4.png" alt="Screenshot">
223    
224     <p>
225     From the "Summary" tab, you can click the links to get a detailed view of a JavaScript source file.
226     </p>
227    
228     <img src="screenshot5.png" alt="Screenshot">
229    
230 siliconforks 14 <h2>Inverted mode</h2>
231    
232     <p>
233     In some circumstances it may be difficult to execute your code within the
234     JSCoverage "Browser" tab. For example, the code may assume that it is running in
235     the top-level browser window, generating errors if it is executed from within a
236     frame. JSCoverage has an alternative mode of operation, called <dfn>inverted
237     mode</dfn>, which may be useful in this situation.
238     </p>
239    
240     <p>
241     Normally you load <code>jscoverage.html</code> in your web browser, and in its
242     "Browser" tab you launch your test code. In inverted mode, you do the
243     opposite: you load your test page directly in your web browser, and from there
244     you launch JSCoverage. To do this you need to add some code to your test page:
245     </p>
246    
247     <pre>
248     window.open("path/to/jscoverage.html");
249     </pre>
250    
251     <p>
252     The <code>"path/to/jscoverage.html"</code> should be a URL pointing to the
253     location of the <code>jscoverage.html</code> file (remember, this will be in the
254     top level of the <var>DESTINATION-DIRECTORY</var> you specified when running
255     the <code>jscoverage</code> executable).
256     </p>
257    
258     <p>
259     You can place this code wherever you like in your page: for example, you could
260     attach it to a button:
261     </p>
262    
263     <pre>
264     &lt;button onclick='window.open("path/to/jscoverage.html");'&gt;Coverage report&lt;/button&gt;
265     </pre>
266    
267     <p>
268     An example is located in the <code>doc/example-inverted</code> directory.
269     You can instrument the code and launch the <code>index.html</code> page:
270     </p>
271    
272     <pre>
273     jscoverage doc/example-inverted doc/instrumented-inverted
274     firefox "doc/instrumented-inverted/index.html"
275     </pre>
276    
277     <p>
278     From this page, you select one of the radio buttons and then click the "Coverage
279     report" button to launch the JSCoverage report.
280     </p>
281    
282 siliconforks 2 <h2>Caveats</h2>
283    
284     <ul>
285     <li>JSCoverage adds instrumentation to JavaScript code, which will slow down execution speed.
286     Expect instrumented code to take at least twice as much time to run.
287     <li>JSCoverage currently instruments only <code>.js</code> files; it does not instrument code in <code>&lt;script&gt;</code>
288     elements in HTML files.
289     <li>HTML files must use relative URLs to reference scripts. If you use an absolute URL, your page will reference
290     the original uninstrumented script rather than the instrumented one, and no code coverage data will be collected.
291     <li>JSCoverage instruments physical lines of code rather than logical JavaScript statements; it works bests with code
292     that has exactly one statement per line. If you put multiple statements on a line, or split a line across two or more
293     statements, you may get strange results.
294     <li>JSCoverage uses frames. Some web pages that use frames may not function properly when run under JSCoverage, especially
295     those which try to access the top-level frame (<code>window.top</code>, <code>target="_top"</code>, etc.).
296     <li>JSCoverage is alpha software. Use at your own risk.
297     </ul>
298    
299     <address>
300     Copyright &copy; 2007 siliconforks.com<br>
301     Last updated July 8, 2007<br>
302     <a href="mailto:jscoverage@siliconforks.com">jscoverage@siliconforks.com</a>
303     </address>
304    
305     </body>
306     </html>

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