# Rcov 0.4.0 (code coverage) - scriptability, accuracy, unrott

**URL:** <https://www.ruby-forum.com/t/rcov-0-4-0-code-coverage-scriptability-accuracy-unrott/61250>\
**Category:** Ruby\
**Created:** [May 22, 2006, 12:29pm UTC](https://www.ruby-forum.com/t/rcov-0-4-0-code-coverage-scriptability-accuracy-unrott/61250 "2006-05-22T12:29:19Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![tulkas](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/5daacb/32.png) [@tulkas](https://www.ruby-forum.com/u/tulkas)\
**Post date:** [May 22, 2006, 12:29pm UTC](https://www.ruby-forum.com/t/rcov-0-4-0-code-coverage-scriptability-accuracy-unrott/61250/1 "2006-05-22T12:29:19Z")

</div>

Source code, additional information, screenshots… available at  
[eigenclass.org](http://eigenclass.org/hiki.rb?rcov)  
Release information:  
[eigenclass.org](http://eigenclass.org/hiki.rb?rcov+0.4.0)

You can find a sample code coverage report generated by rcov at  
[eigenclass.org](http://eigenclass.org/static/rcov-sample-report/)

If you’re on win32, you can also find a pre-built rcovrt.so (which makes  
code coverage analysis \>100 times faster) in the above-mentioned pages.

# Overview

rcov is a tool for simple code coverage analysis in Ruby. It features:

- fast execution: 20-300 times faster than previous tools
- multiple analysis modes
- fairly accurate coverage information through code linkage inference  
using  
simple heuristics
- XHTML and several kinds of text reports
- easy automation with Rake via a RcovTask
- colorblind-friendliness

# What’s new in 0.4.0

See [eigenclass.org](http://eigenclass.org/hiki.rb?rcov+0.4.0) for the detailed change  
summary.

rcov 0.4.0 is really feature-packed, and (hopefully) less buggy than  
previous  
releases. This can be ascribed in large part to the use of rcov on  
itself to  
achieve better test coverage. Nearly 100 changesets went into rcov  
0.4.0.

Starting with the most obvious changes, the XHTML output looks much  
better  
now with the new color-scheme. Plain text output formats have also  
improved  
considerably.

rcov 0.4.0 is much easier to use from external scripts, and invoking  
rcov  
from your Rakefile takes no effort with the included Rcov::RcovTask; it  
can  
take as little as:

```
require 'rcov/rcovtask'
Rcov::RcovTask.new

```

Really! This creates a task named “rcov” which will run the tests  
matching  
test/test\*.rb and create a XHTML report. And a nice textual report on  
stdout). And a clobber\_rcov task, which the main clobber target will  
depend  
on, to delete the former.

However, sometimes that lone Rcov::RcovTask.new will not suffice; this  
would  
be a more realistic example:

```
# if you don't like the default description
desc "Analyze code coverage of the unit tests."
Rcov::RcovTask.new do |t|
  # change the glob pattern in the next line
  t.test_files = FileList['test/test*.rb']
  t.rcov_opts << "--sort coverage" # sort by increasing coverage 

```

rate  
end

See README.rake in the distribution tarball (or the RDoc documentation,  
which  
includes it) for more information about Rcov::RcovTask.

Parts of the code have been moved into a reusable library that allows  
you to  
build on top of rcov’s coverage analysis capabilities. This change  
allowed for  
much better testing of rcov’s internals, which helped squash many bugs  
and add  
features while making the overall code look better thanks to some  
long-needed  
refactoring.

## Short summary of user-visible changes

- easy automation via Rake using the bundled Rcov::RcovTask
- better heuristics: supports heredocs at last, including variants your  
editor  
is probably unable to handle, and =begin/=end comments
- –rails option to ignore files under vendor/, enviroment/ and config/
- parts of the runtime exposed and documented for external use
- new color scheme, with alternating shades of the base colors
- -w to set $VERBOSE=true (turns on warnings)
- –text-report and --text-summary
- –sort and --sort-reverse for the summaries and reports
- –threshold and --only-uncovered
- –replace-progname

## Backwards incompatible changes

- renamed --text to --text-counts and --rich-text to --text-coverage:  
they  
were misnamed to begin with
- changed the meaning of -t and -T (–text-summary and --text-report)
- $0 is not changed by default for each loaded file anymore; the old  
behavior (modulo a small bugfix) can be reproduced with  
–replace-progname

# Thanks (do tell if I forgot to list your name)

Robert F.:

- helped to refine the color scheme
- very valuable suggestions; a large percentage of the new functionality  
in  
0.4.0 is a consequence of his requests

Andre N.:

- identified a couple bugs in the heuristics that eluded my testing

# Downloading

The last version is available at  
[eigenclass.org](http://eigenclass.org/hiki.rb?rcov)

# How do I use it?

Just use rcov to run your program (instead of ruby), and a number of  
XHTML  
files with the code coverage information will be generated, e.g.

rcov test/\*.rb

will execute all the .rb files under test/ and generate the code  
coverage report  
under coverage/. rcov can also operate in “bogo-profiling mode”  
and output the relevant information in alternative formats. Use  
rcov -h  
for more information.

# Sample output

See [eigenclass.org](http://eigenclass.org/hiki.rb?rcov) (once again) for screenshots.  
A sample code coverage report generated by rcov is available at  
[eigenclass.org](http://eigenclass.org/static/rcov-sample-report/)

Text reports (also used by default in RcovTasks) resemble

±----------------------------------------------------±------±------±-------+  
| File | Lines | LOC | COV |  
±----------------------------------------------------±------±------±-------+  
|app/controllers/application.rb | 39 | 29 | 31.0% |  
|app/helpers/application\_helper.rb | 147 | 119 | 23.5% |  
|app/models/aggregations/tada.rb | 75 | 45 | 31.1% |  
|app/models/aggregations/upcoming.rb | 78 | 48 | 29.2% |  
|app/models/article.rb | 109 | 78 | 67.9% |  
|app/models/category.rb | 30 | 23 | 60.9% |  
|app/models/sidebar.rb | 36 | 27 | 40.7% |  
|components/plugins/sidebars/archives\_controller.rb | 35 | 27 | 29.6% |  
|components/plugins/sidebars/category\_controller.rb | 20 | 16 | 50.0% |  
|components/plugins/sidebars/delicious\_controller.rb | 20 | 16 | 50.0% |  
|components/plugins/sidebars/flickr\_controller.rb | 20 | 16 | 50.0% |  
|components/plugins/sidebars/fortythree\_controller.rb | 20 | 16 | 50.0% |  
|…s/plugins/sidebars/fortythreeplaces\_controller.rb | 20 | 16 | 50.0% |  
|components/plugins/sidebars/static\_controller.rb | 27 | 24 | 29.2% |  
|components/plugins/sidebars/tada\_controller.rb | 20 | 16 | 50.0% |  
|components/plugins/sidebars/technorati\_controller.rb | 20 | 16 | 50.0% |  
|components/plugins/sidebars/upcoming\_controller.rb | 20 | 16 | 50.0% |  
|components/plugins/sidebars/xml\_controller.rb | 16 | 13 | 53.8% |  
|components/sidebars/sidebar\_controller.rb | 110 | 80 | 32.5% |  
|lib/html\_engine.rb | 29 | 23 | 78.3% |  
|lib/login\_system.rb | 85 | 34 | 23.5% |  
|lib/migrator.rb | 28 | 22 | 40.9% |  
|lib/renderfix.rb | 32 | 25 | 16.0% |  
|lib/xmlrpc\_fix.rb | 13 | 12 | 25.0% |  
±----------------------------------------------------±------±------±-------+  
|Total | 1754 | 1251 | 60.1% |  
±----------------------------------------------------±------±------±-------+  
60.1% 42 file(s) 1754 Lines 1251 LOC

This was run with --threshold 80, meaning that only files under 80%  
coverage  
are shown in the table, but the overall statistics include all analyzed  
files.

The textual output with execution count information looks like this:

# $ rcov --no-html --text-counts b.rb

# ./b.rb

```
                                                                   | 

```

2  
a, b, c = (1…3).to\_a |  
2  
10.times do |  
1  
a += 1 |  
10  
20.times do |i| |  
10  
b += i |  
200  
b.times do |  
200  
c += (j = (b-a).abs) \> 0 ? j : 0 |  
738800  
end |  
0  
end |  
0  
end |  
0

## License

rcov is released under the terms of Ruby’s license.  
rcov includes xx 0.1.0, which is subject to the following conditions:

ePark Labs Public License version 1  
Copyright (c) 2005, ePark Labs, Inc. and contributors  
All rights reserved.

Redistribution and use in source and binary forms, with or without  
modification,  
are permitted provided that the following conditions are met:

1. Redistributions of source code must retain the above copyright  
notice, this  
list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright  
notice,  
this list of conditions and the following disclaimer in the  
documentation  
and/or other materials provided with the distribution.
3. Neither the name of ePark Labs nor the names of its contributors  
may be  
used to endorse or promote products derived from this software  
without  
specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS “AS  
IS” AND  
ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE  
IMPLIED  
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE  
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE  
LIABLE FOR  
ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL  
DAMAGES  
(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR  
SERVICES;  
LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED  
AND ON  
ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT  
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF  
THIS  
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

---

<div class="post-metadata">

**Author:** ![tulkas](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/5daacb/32.png) [@tulkas](https://www.ruby-forum.com/u/tulkas)\
**Post date:** [May 22, 2006, 6:12pm UTC](https://www.ruby-forum.com/t/rcov-0-4-0-code-coverage-scriptability-accuracy-unrott/61250/2 "2006-05-22T18:12:29Z")

</div>

This is awesome. It’s enlightening and sad to see the coverage of some  
of my unit tests, but without a doubt I’m hooked. Visually looking at  
the test coverage (or lack thereof) is really much more effective than I  
thought. If anything this will help to be a lot more conscious about  
creating solid test suites, rather than cherry picking the easy/obvious  
ones that most likely don’t do the job like they should.

When do we get a gem?

Thanks a lot,  
Jeff

---

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**Author:** ![tulkas](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/5daacb/32.png) [@tulkas](https://www.ruby-forum.com/u/tulkas)\
**Post date:** [May 22, 2006, 10:21pm UTC](https://www.ruby-forum.com/t/rcov-0-4-0-code-coverage-scriptability-accuracy-unrott/61250/3 "2006-05-22T22:21:40Z")

</div>

On Tue, 2006-05-23 at 01:09 +0900, Jeff R. wrote:

> This is awesome. It’s enlightening and sad to see the coverage of some  
> of my unit tests, but without a doubt I’m hooked. Visually looking at  
> the test coverage (or lack thereof) is really much more effective than I  
> thought. If anything this will help to be a lot more conscious about  
> creating solid test suites, rather than cherry picking the easy/obvious  
> ones that most likely don’t do the job like they should.
> 
> When do we get a gem?

Mauricio, I’ll hook you up with gem builds if you want. I use rcov a  
lot and having gems makes it easier for me to get other developers to  
use it.

---

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**Author:** ![tulkas](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/5daacb/32.png) [@tulkas](https://www.ruby-forum.com/u/tulkas)\
**Post date:** [May 23, 2006, 12:06am UTC](https://www.ruby-forum.com/t/rcov-0-4-0-code-coverage-scriptability-accuracy-unrott/61250/4 "2006-05-23T00:06:18Z")

</div>

On Tue, May 23, 2006 at 05:17:47AM +0900, Zed S. wrote:

> Mauricio, I’ll hook you up with gem builds if you want. I use rcov a  
> lot and having gems makes it easier for me to get other developers to  
> use it.

The one thing that has been blocking (or at least pushing down the TODO  
list)  
the RubyGems package was how to combine it with cross-compilation for  
win32,  
since I figured a RubyGems package would be of most value to win32 users  
who  
have no access to a C toolchain. There are a few other problems I’d have  
liked  
to solve, but they’re much more general and probably addressable at  
RubyGems’  
level (C runtime compatibility, ABI checking…).

A “normal” RubyGems package (i.e. one that requires a C compiler) should  
be  
very easy, so I should be able to get one out fairly quickly.