# Rcov 0.8.0: new output modes, fix for RSpec woes, superior E

**URL:** <https://www.ruby-forum.com/t/rcov-0-8-0-new-output-modes-fix-for-rspec-woes-superior-e/87135>\
**Category:** Ruby\
**Created:** [February 28, 2007, 1:07pm UTC](https://www.ruby-forum.com/t/rcov-0-8-0-new-output-modes-fix-for-rspec-woes-superior-e/87135 "2007-02-28T13:07:05Z")\
**Posts on this page:** 8\
**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:** [February 28, 2007, 1:07pm UTC](https://www.ruby-forum.com/t/rcov-0-8-0-new-output-modes-fix-for-rspec-woes-superior-e/87135/1 "2007-02-28T13:07:05Z")

</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-0.8.0)  
Sample fully cross-referenced report at  
[eigenclass.org](http://eigenclass.org/static/rcov-sample-report-full-crossref/)

This release includes two RubyGems packages: a binary one for Win32 and  
a  
platform-independent one for all those with a compiler, (or a lot of  
patience,  
if willing to run rcov in pure-Ruby mode), so  
gem install rcov  
should work once the packages have propagated to the mirror network.

# Overview

rcov is a code coverage tool for Ruby. It is commonly used for viewing  
overall  
test coverage of target code. It features:

- fast execution: 20-300 times faster than previous tools
- multiple analysis modes: standard, bogo-profile, “intentional  
testing”,  
dependency analysis…
- detection of uncovered code introduced since the last run  
(“differential  
code coverage”)
- fairly accurate coverage information through code linkage inference  
using  
simple heuristics
- cross-referenced XHTML and several kinds of text reports
- support for easy automation with Rake and Rant
- colorblind-friendliness

# What’s new in 0.8.0

## Features

- –annotate mode, which dumps annotated source code which can be used  
to  
follow the control flow (very useful when reading third-party code)
- –gcc option to display uncovered lines in GCC error format
- superior Emacs support: running rcov, jumping to uncovered code,  
navigate  
through cross-referenced annotated code
- –[no-]validator-links

## Bugfixes

- differential code coverage reports work with filenames containing  
special  
characters
- fixed recent segfaults happening with rspec
- more care name mangling

## Minor enhancements

- relevant summary values are identified using separate CSS classes  
(microformat-style)

# Special thanks go to

rubikitch

- implemented --annotate mode
- implemented --gcc option
- superior emacs support
- testing, refactoring…
- many other things, see darcs changes

Zed A. Shaw

- reported and fixed segfault triggered by rspec

Jan S.

- reported typo in rcovtask.rb’s RDoc

Thomas L.

- fixed the bug which broke differential reports for filenames with  
special characters

# How do I use it?

In the common scenario, your tests are under test/ and the target code  
(whose coverage you want) is in lib/. In that case, all you have to do  
is  
use rcov to run the tests (instead of testrb), and a number of XHTML  
files  
with the code coverage information will be generated, e.g.

```
rcov -Ilib test/*.rb

```

will execute all the .rb files under test/ and generate the code  
coverage  
report for the target code (i.e. for the files in lib/) under coverage/.  
The  
target code needs not be under lib/; rcov will detect is as long as it  
is  
require()d by the tests. rcov is smart enough to ignore “uninteresting”  
files: the tests themselves, files installed in Ruby’s standard  
locations,  
etc. See rcov --help for the list of regexps rcov matches filenames  
against.

rcov can also be used from Rake; see README.rake or the RDoc  
documentation  
for more information.

rcov can output information in several formats, and perform different  
kinds  
of analyses in addition to plain code coverage. See rcov --help for a  
description of the available options.

# Sample output

See [eigenclass.org](http://eigenclass.org/hiki.rb?rcov) (once again) for screenshots.

The text report (also used by default in RcovTasks) resembles

±----------------------------------------------------±------±------±-------+  
| File | Lines | LOC | COV |  
±----------------------------------------------------±------±------±-------+  
|lib/rcov.rb | 572 | 358 | 91.3% |  
±----------------------------------------------------±------±------±-------+  
|Total | 572 | 358 | 91.3% |  
±----------------------------------------------------±------±------±-------+  
91.3% 1 file(s) 572 Lines 358 LOC

The (undecorated) 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

rcov can detect when you’ve added code that was not covered by your unit  
tests:

```
$ rcov --text-coverage-diff --no-color test/*.rb
Started
.......................................
Finished in 1.163085 seconds.

39 tests, 415 assertions, 0 failures, 0 errors

================================================================================
!!!!! Uncovered code introduced in lib/rcov.rb

### lib/rcov.rb:207

```

def precompute\_coverage(comments\_run\_by\_default = true)  
changed = false  
lastidx = lines.size - 1  
if (!is\_code?(lastidx) || /^ **END** $/ =~ @lines[-1]) &&  
!@coverage[lastidx]  
!! # mark the last block of comments  
!! @coverage[lastidx] ||= :inferred  
!! (lastidx-1).downto(0) do |i|  
!! break if is\_code?(i)  
!! @coverage[i] ||= :inferred  
!! end  
!! end  
(0…lines.size).each do |i|  
next if @coverage[i]  
line = @lines[i]

## 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:** [February 28, 2007, 1:48pm UTC](https://www.ruby-forum.com/t/rcov-0-8-0-new-output-modes-fix-for-rspec-woes-superior-e/87135/2 "2007-02-28T13:48:41Z")

</div>

Thanks for new version. But I get an error:

> rcov -v  
> rcov 0.8.0 2007-02-28

> rcov -Ilib test/test\_read.rb  
> Loaded suite /usr/bin/rcov  
>   
> Finished in 2.204768 seconds.

7 tests, 25 assertions, 0 failures, 0 errors  
(eval):229:in `method_missing': no id given (ArgumentError) from (eval):229:in`method\_missing’  
from  
/usr/lib/ruby/gems/1.8/gems/rcov-0.8.0.1/lib/rcov/report.rb:36:in  
`initialize' from /usr/lib/ruby/gems/1.8/gems/rcov-0.8.0.1/lib/rcov/report.rb:61:in`mangle\_filename’  
from  
/usr/lib/ruby/gems/1.8/gems/rcov-0.8.0.1/lib/rcov/report.rb:691:in  
`format_overview' from (eval):104:in`create’  
from (eval):80:in `tracking_additions' from (eval):103:in`create’  
from (eval):493:in `td_' ... 48 levels... from /usr/lib/ruby/gems/1.8/gems/rcov-0.8.0.1/lib/rcov.rb:628:in`dump\_coverage\_info’  
from /usr/lib/ruby/gems/1.8/gems/rcov-0.8.0.1/lib/rcov.rb:628:in  
`dump\_coverage\_info’  
from /usr/lib/ruby/gems/1.8/gems/rcov-0.8.0.1/bin/rcov:405  
from /usr/lib/ruby/1.8/test/unit.rb:285

regards  
Jan

---

<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:** [February 28, 2007, 3:48pm UTC](https://www.ruby-forum.com/t/rcov-0-8-0-new-output-modes-fix-for-rspec-woes-superior-e/87135/3 "2007-02-28T15:48:49Z")

</div>

On Wed, Feb 28, 2007 at 09:48:42PM +0900, Jan F. wrote:

> Thanks for new version. But I get an error:  
> […]  
> 7 tests, 25 assertions, 0 failures, 0 errors  
> (eval):229:in `method_missing': no id given (ArgumentError) from (eval):229:in `method\_missing’  
> from  
> /usr/lib/ruby/gems/1.8/gems/rcov-0.8.0.1/lib/rcov/report.rb:36:in  
> `initialize’  
> from

This was an interesting bug report, I’ve found a possible bug in Ruby  
(new behavior introduced in 1.8.5) thanks to it.

Here’s the part of the story that relates to your problem; the Ruby  
build  
(more precisely the stdlib) you’re using predates this:

```
Sat Jun 17 14:53:32 2006 Tanaka A. <removed_email_address@domain.invalid>

  * lib/pathname.rb: backport from 1.9.
    (Kernel#Pathname): new method.

```

(iow. you’re probably using ruby \< 1.8.5).

There’s a chance rcov will work if you apply this patch:

Wed Feb 28 15:29:58 CET 2007 Mauricio F. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)

- lib/rcov/report.rb: use Pathname.new instead of Pathname for  
compatibility with Ruby \< 1.8.5.  
diff -rN -u old-head/lib/rcov/report.rb new-head/lib/rcov/report.rb  
— old-head/lib/rcov/report.rb 2007-02-28 15:30:47.000000000 +0100  
+++ new-head/lib/rcov/report.rb 2007-02-28 15:30:47.000000000 +0100  
@@ -33,7 +33,7 @@  
@callsite\_index = nil

- 

```
       h[base] = Pathname(base).cleanpath.to_s.gsub(%r{^\w:[/\\]}, 

```

“”).gsub(/./, “\_”).gsub(/[\/]/, “-”) + “.html”

- 

```
       h[base] = 

```

Pathname.new(base).cleanpath.to\_s.gsub(%r{^\w:[/\]}, “”).gsub(/./,  
“\_”).gsub(/[\/]/, “-”) + “.html”  
}  
end

I’d be grateful if you could run rcov after applying the above patch and  
tell  
me if it works. If so, 0.8.1 will follow shortly.

The unit tests seem to indicate that cross-referenced reports might not  
work  
under ruby \<1.8.5, but the basic functionality (code coverage) does.  
I’ll  
document that.

---

<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:** [February 28, 2007, 4:07pm UTC](https://www.ruby-forum.com/t/rcov-0-8-0-new-output-modes-fix-for-rspec-woes-superior-e/87135/4 "2007-02-28T16:07:53Z")

</div>

It looks like rcov won’t cover an empty rescue clause. I posted a  
detailed bug report on [eigenclass.org](http://eigenclass.org/hiki.rb?rcov-0.8.0).

Awesome tool in general, however. THANKS!!!

---

<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:** [February 28, 2007, 4:35pm UTC](https://www.ruby-forum.com/t/rcov-0-8-0-new-output-modes-fix-for-rspec-woes-superior-e/87135/5 "2007-02-28T16:35:47Z")

</div>

Mauricio F. wrote:

> This was an interesting bug report, I’ve found a possible bug in Ruby  
> (new behavior introduced in 1.8.5) thanks to it.  
> Yes:  
> % ruby -v  
> ruby 1.8.4 (2005-12-24) [i486-linux]

> I’d be grateful if you could run rcov after applying the above patch and  
> tell  
> me if it works. If so, 0.8.1 will follow shortly.  
> Yes. 🙂

regards  
Jan

---

<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:** [February 28, 2007, 9:17pm UTC](https://www.ruby-forum.com/t/rcov-0-8-0-new-output-modes-fix-for-rspec-woes-superior-e/87135/6 "2007-02-28T21:17:11Z")

</div>

On Thu, Mar 01, 2007 at 12:35:49AM +0900, Jan F. wrote:

> Mauricio F. wrote:
> 
> > This was an interesting bug report, I’ve found a possible bug in Ruby  
> > (new behavior introduced in 1.8.5) thanks to it.  
> > Yes:  
> > % ruby -v  
> > ruby 1.8.4 (2005-12-24) [i486-linux]
> 
> > I’d be grateful if you could run rcov after applying the above patch and  
> > tell me if it works. If so, 0.8.1 will follow shortly.  
> > Yes. 🙂

I finally decided to leave 0.8.1 for later, but I applied the patch to  
0.8.0.2, available in tarball and gem formats.

---

<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:** [March 1, 2007, 1:16am UTC](https://www.ruby-forum.com/t/rcov-0-8-0-new-output-modes-fix-for-rspec-woes-superior-e/87135/7 "2007-03-01T01:16:49Z")

</div>

On Thu, Mar 01, 2007 at 07:22:34AM +0900, Faisal N Jawdat wrote:

> On Feb 28, 2007, at 3:16 PM, Mauricio F. wrote:
> 
> > I finally decided to leave 0.8.1 for later, but I applied the patch to  
> > 0.8.0.2, available in tarball and gem formats.
> 
> What does that do to the version on RubyForge?

The version on Rubyforge is 0.8.0.2; both the gem and the tarball for  
0.8.0.2  
are available in the file area of the ‘rcov’ project. If you’re using  
1.8.5,  
0.8.0 and 0.8.0.2 will behave identically. The only differences are the  
patch  
I posted before and a similar modification in the same file that makes  
it work  
with ruby \<1.8.5.

---

<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:** [February 28, 2007, 11:23pm UTC](https://www.ruby-forum.com/t/rcov-0-8-0-new-output-modes-fix-for-rspec-woes-superior-e/87135/8 "2007-02-28T23:23:35Z")

</div>

On Feb 28, 2007, at 3:16 PM, Mauricio F. wrote:

> I finally decided to leave 0.8.1 for later, but I applied the patch to  
> 0.8.0.2, available in tarball and gem formats.

What does that do to the version on RubyForge?

-faisal