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1 <!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>
9 <h1>JSCoverage user manual</h1>
11 <p>
12 JSCoverage is a tool used to measure code coverage in JavaScript
13 programs.
14 </p>
16 <p>
17 JSCoverage has two components:
18 </p>
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>
26 <h2>Installing JSCoverage</h2>
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>
34 <p>
35 You can extract and compile the code with the following commands:
36 </p>
38 <pre>
39 tar jxvf jscoverage-0.3.tar.bz2
40 cd jscoverage-0.3/
41 ./configure
42 make
43 </pre>
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>
50 <pre>
51 make install
52 </pre>
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>
60 <h2>Using JSCoverage</h2>
62 <p>
63 Using JSCoverage requires three steps:
64 </p>
66 <h3>1. Instrumenting code</h3>
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>
73 <pre>
74 jscoverage <var>SOURCE-DIRECTORY</var> <var>DESTINATION-DIRECTORY</var>
75 </pre>
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>
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>
96 <table>
97 <tr>
98 <td><pre>
99 <var>SOURCE-DIRECTORY</var>/
100 dir/
101 index.html
102 script.js
104 </pre></td>
105 <td class="arrow">&rarr;</td>
106 <td><pre>
108 dir/
109 index.html
110 script.js [instrumented]
111 jscoverage.html
112 </pre></td>
113 </tr>
114 </table>
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>
121 <h3>2. Running instrumented code in the web application</h3>
123 <p>
124 Open <code>jscoverage.html</code> in your web browser.
125 The page contains a tabbed user interface:
126 </p>
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>
136 <img src="screenshot.png" alt="Screenshot">
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>
146 <h3>3. Generating the coverage report</h3>
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>
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>
163 <h2>Example</h2>
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>
171 <h3>1. Instrumenting code</h3>
173 <p>
174 From the main distribution directory, execute the command:
175 </p>
177 <pre>
178 jscoverage doc/example doc/instrumented
179 </pre>
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>
186 <h3>2. Executing instrumented code</h3>
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>
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>
202 <pre>
203 firefox "doc/instrumented/jscoverage.html?index.html"
204 </pre>
206 <img src="screenshot2.png" alt="Screenshot">
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>
213 <img src="screenshot3.png" alt="Screenshot">
215 <h3>3. Generating the coverage report</h3>
217 <p>
218 Once you have executed the JavaScript code, you are instructed to click on the
219 "Summary" tab.
220 </p>
222 <img src="screenshot4.png" alt="Screenshot">
224 <p>
225 You can click the checkbox to show a list of statements missed during execution.
226 </p>
228 <img src="screenshot5.png" alt="Screenshot">
230 <p>
231 You can click one of the links to get a detailed view of a JavaScript source file.
232 </p>
234 <img src="screenshot6.png" alt="Screenshot">
236 <h2>Inverted mode</h2>
238 <p>
239 In some situations it may be difficult to execute your code within the
240 JSCoverage "Browser" tab. For example, the code may assume that it is running in
241 the top-level browser window, generating errors if it is executed from within a
242 frame. JSCoverage has an alternative mode of operation, called <dfn>inverted
243 mode</dfn>, which may be useful in this case.
244 </p>
246 <p>
247 Normally you load <code>jscoverage.html</code> in your web browser, and in its
248 "Browser" tab you launch your test code. In inverted mode, you do the
249 opposite: you load your test page directly in your web browser, and from there
250 you launch JSCoverage. To do this you need to add some code to your test page:
251 </p>
253 <pre>
254 window.open("path/to/jscoverage.html");
255 </pre>
257 <p>
258 The <code>"path/to/jscoverage.html"</code> should be a URL pointing to the
259 location of the <code>jscoverage.html</code> file (remember, this will be in the
260 top level of the <var>DESTINATION-DIRECTORY</var> you specified when running
261 the <code>jscoverage</code> executable).
262 </p>
264 <p>
265 You can place this code wherever you like in your page: for example, you could
266 attach it to a button:
267 </p>
269 <pre>
270 &lt;button onclick='window.open("path/to/jscoverage.html");'&gt;Coverage report&lt;/button&gt;
271 </pre>
273 <p>
274 Note that you <em>must</em> use a <code>window.open</code> call; simply making a
275 link to <code>jscoverage.html</code> is not sufficient.
276 </p>
278 <p>
279 An example is located in the <code>doc/example-inverted</code> directory.
280 You can instrument the code and launch the <code>index.html</code> page:
281 </p>
283 <pre>
284 jscoverage doc/example-inverted doc/instrumented-inverted
285 firefox "doc/instrumented-inverted/index.html"
286 </pre>
288 <p>
289 From this page, you select one of the radio buttons and then click the "Coverage
290 report" button to launch the JSCoverage report.
291 </p>
293 <h2>Command line options</h2>
295 <p>
296 The <code>jscoverage</code> program accepts the following options:
297 </p>
299 <dl>
300 <dt><code>-h</code>, <code>--help</code>
301 <dd>Display a brief help message.
302 <dt><code>-V</code>, <code>--version</code>
303 <dd>Display the version of the program.
304 <dt><code>-v</code>, <code>--verbose</code>
305 <dd>Explain what is being done.
306 <dt><code>--exclude=<var>PATH</var></code>
307 <dd>The command
308 <pre>
309 jscoverage --exclude=<var>PATH</var> <var>SOURCE-DIRECTORY</var> <var>DESTINATION-DIRECTORY</var>
310 </pre>
311 copies <var>SOURCE-DIRECTORY</var> to <var>DESTINATION-DIRECTORY</var>
312 recursively, but does not copy <var>SOURCE-DIRECTORY</var>/<var>PATH</var>.
313 <var>PATH</var> must be a complete path relative to <var>SOURCE-DIRECTORY</var>.
314 <var>PATH</var> can be a file or a directory (in which case the directory and
315 its entire contents are skipped). This option may be given multiple times.
316 <dt><code>--no-instrument=<var>PATH</var></code>
317 <dd>The command
318 <pre>
319 jscoverage --no-instrument=<var>PATH</var> <var>SOURCE-DIRECTORY</var> <var>DESTINATION-DIRECTORY</var>
320 </pre>
321 copies <var>SOURCE-DIRECTORY</var> to <var>DESTINATION-DIRECTORY</var>
322 recursively, but does not instrument any JavaScript code in
323 <var>SOURCE-DIRECTORY</var>/<var>PATH</var>. <var>PATH</var> must be a complete
324 path relative to <var>SOURCE-DIRECTORY</var>. <var>PATH</var> can be a
325 (JavaScript) file or a directory (in which case any JavaScript files located
326 anywhere underneath the directory are not instrumented). This option may be
327 given multiple times.
328 </dl>
330 <h2>Query string options</h2>
332 <p>
333 When accessing <code>jscoverage.html</code> in a web browser, you may provide a
334 query string consisting of options separated by ampersand (<code>&amp;</code>)
335 or semicolon (<code>;</code>). Any option not containing an equals sign
336 (<code>=</code>) is considered to be a URL which will be loaded in the "Browser"
337 tab.
338 </p>
340 <dl>
341 <dt><code>u=<var>URL</var></code>, <code>url=<var>URL</var></code>
342 <dd>Load <var>URL</var> in the "Browser" tab. (This is the same as specifying
343 an option without an equals sign.)
344 <dt><code>m=<var>BOOLEAN</var></code>, <code>missing=<var>BOOLEAN</var></code>
345 <dd>Determines whether to initially display the "Missing" column in the "Summary"
346 tab. <var>BOOLEAN</var> can be
347 <code>true</code>, <code>t</code>, <code>yes</code>, <code>y</code>, <code>on</code>, <code>1</code>
348 (to display the "Missing" column), or
349 <code>false</code>, <code>f</code>, <code>no</code>, <code>n</code>, <code>off</code>, <code>0</code>
350 (to hide the "Missing" column). By default, the "Missing" column is not displayed.
351 </dl>
353 <h2>Caveats</h2>
355 <ul>
356 <li>JSCoverage adds instrumentation to JavaScript code, which will slow down execution speed.
357 Expect instrumented code to take at least twice as much time to run.
358 <li>JSCoverage currently instruments only <code>.js</code> files; it does not instrument code in <code>&lt;script&gt;</code>
359 elements in HTML files.
360 <li>HTML files must use relative URLs to reference scripts. If you use an absolute URL, your page will reference
361 the original uninstrumented script rather than the instrumented one, and no code coverage data will be collected.
362 <li>JSCoverage instruments physical lines of code rather than logical JavaScript statements; it works bests with code
363 that has exactly one statement per line. If you put multiple statements on a line, or split a line across two or more
364 statements, you may get strange results.
365 <li>JSCoverage uses frames. Some web pages that use frames may not function properly when run under JSCoverage, especially
366 those which try to access the top-level frame (<code>window.top</code>, <code>target="_top"</code>, etc.).
367 <li>JSCoverage is alpha software. Use at your own risk.
368 </ul>
370 <address>
371 Copyright &copy; 2007 siliconforks.com<br>
372 Last updated August 26, 2007<br>
373 <a href="mailto:jscoverage@siliconforks.com">jscoverage@siliconforks.com</a>
374 </address>
376 </body>
377 </html>

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