# Rcov 0.3.0 (code coverage tool): happier Rails

**URL:** <https://www.ruby-forum.com/t/rcov-0-3-0-code-coverage-tool-happier-rails/59677>\
**Category:** Ruby\
**Created:** [May 5, 2006, 11:44am UTC](https://www.ruby-forum.com/t/rcov-0-3-0-code-coverage-tool-happier-rails/59677 "2006-05-05T11:44:45Z")\
**Posts on this page:** 1\
**Page:** 1

<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 5, 2006, 11:44am UTC](https://www.ruby-forum.com/t/rcov-0-3-0-code-coverage-tool-happier-rails/59677/1 "2006-05-05T11:44:45Z")

</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+0.3.0)

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
- more accurate coverage information through code linkage inference  
using  
simple heuristics
- XHTML, plain text, ANSI-escaped text outputs
- convenient interface
- colorblind-friendliness

## What’s new in 0.3.0

A change summary can be found at  
[http://eigenclass.org/hiki.rb?rcov+0.3.0](http://eigenclass.org/hiki.rb?rcov+0.3.0)

Even shorter summary:

rcov 0.3.0 introduces a number of features that simplify the analysis of  
Rails  
applications.

The new code coverage analysis mode, --test-unit-only, records  
exclusively code  
executed inside Test::Unit::TestCase(s). Another important addition is  
the  
ability to detect aliased source files: this was very needed to analyze  
Rails  
apps, where a file could get loaded under several different names, due  
to the  
extensive usage of #require with relative paths.

Features  
\* --exclude-only  
\* consolidate multiple references to the same underlying .rb file  
(much needed for Rails)  
\* --test-unit-only  
Fixes  
\* consider and/op operators  
\* honor --no-color in (rich) text mode  
\* output valid XHTML indices

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

Tom Dolbilin:

- identified and fixed backslash problem on win32 for generated  
filenames

Andrew K.:

- made the index XHTML compliant
- consolidate multiple references to the same underlying .rb file

Robert F.:

- pointed me to dynamic uses of the tracing hooks, provided the  
inspiration  
for RCOV\_\_.run\_hooked

## Downloading

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

## How do I use it? What does it look like?

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 (for the time  
being, plain text with execution count annotations and colored text).  
Use  
rcov -h  
for more information.

## Sample output

See [eigenclass.org](http://eigenclass.org/hiki.rb?rcov) (once again) for screenshots.  
The (undecorated) textual output with execution count information looks  
like this:

# $ rcov --no-html -t 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.