[ANN] rcov 0.7.0 (code coverage for Ruby)

[Mauricio Fernandez]

Source code, additional information, screenshots... available at
http://eigenclass.org/hiki.rb?rcov
Release information:
http://eigenclass.org/hiki.rb?rcov+0.7.0

Sample (fully) cross-referenced report at
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 (as of
14:20 UTC, about 5H since I uploaded them to Rubyforge, they haven't).

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 0.7.0
===================
See http://eigenclass.org/hiki.rb?rcov+0.7.0 for the detailed change summary.

Features
--------
* coverage/callsite data from multiple runs can be aggregated (--aggregate)

Bugfixes
--------
* the SCRIPT_LINES__ workaround works better
* fixed silly bug in coverage data acquisition (line after the correct one
marked in some situations)
* avoid problems with repeated path separators in default ignore list, based
on rbconfig's data


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 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 ||= :inferred
!! end
!! end
(0...lines.size).each do |i|
next if @coverage
line = @lines

Thanks
======
Thomas Leitner:
* reported that the SCRIPT_LINES__ workaround did not always work

Assaph Mehr:
* beta-tested 0.7.0 and found a bug in --aggregate (missing files)

Ryan Kinderman:
* suggested that -Ipath be passed to ruby instead of rcov in RcovTasks

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.

 

[Logan Capaldo]

I am wondering, for a rails project, would this be the correct way
to use
this?

rcov -Ilib test/**/*.rb

That works for me, albeit about 30% of my tests fail then, while
when I run
them using the rake task ("rake"), they all pass. So I suppose I
must be
doing something wrong.


Thanks alot, great project,

http://www.agilewebdevelopment.com/plugins/rails_rcov

That plugin takes a lot of the headache out of using rails + rcov.
(Please don't top post).

 

[Michael Trier]

Mauricio thanks for the excellent tool. I use it every day.

Michael

 

[Assaph Mehr]

I am wondering, for a rails project, would this be the correct way to use
this?

rcov -Ilib test/**/*.rb

That works for me, albeit about 30% of my tests fail then, while when I run
them using the rake task ("rake"), they all pass. So I suppose I must be
doing something wrong.

This was actually discovered on a rails project. In Rails case there
seems to be some weird interaction where running all tests
(integreation and functional for me) causes clashes. The rake tasks
for rails also launch a separate test process for each, and now rcov
mimics that.

Using the coverage.task template provided by Mauricio for rails seems
to fix the issue.

HTH,
Assaph

 

[Mauricio Fernandez]

I am wondering, for a rails project, would this be the correct way to use
this?

rcov -Ilib test/**/*.rb

That works for me, albeit about 30% of my tests fail then, while when I run
them using the rake task ("rake"), they all pass. So I suppose I must be
doing something wrong.

As Assaph said, this can fail in some circumstances, the reason being that
unit, functional and integration tests cannot always be run in the same
process safely; this is why the test task in Rails apps executes them
separately.

So, if you are lucky and there are no clashes, just

rcov --rails -Ilib test/**/*_test.rb

would do. --rails tells rcov to ignore config/, environment/ and vendor/ in
the statistics.

Now, if you see that the outcome of the tests when run as shown above differs
from the results given by rake test (as happened to you), you have to execute
unit, functional and integration tests in three different processes.
You can do it manually as follows:

rm -f coverage.data
rcov --no-html --rails --aggregate coverage.data -Ilib test/unit/*_test.rb
rcov --no-html --rails --aggregate coverage.data -Ilib test/functional/*_test.rb
rcov --rails --aggregate coverage.data -Ilib test/integration/*_test.rb

--aggregate is used to merge the coverage data from the three runs in a
single report; --no-html is used in the first two runs because anyway the
last execution will create the report with all the information.

If you want a recipe to automate that, have a look at
http://eigenclass.org/hiki.rb?rcov+0.7.0
where I show a small snippet you can dump into e.g. lib/tasks/rcov.rake.
It will generate a number of tasks in the test:coverage namespace, as well as
a test:coverage task that runs all the tests under rcov.

Unfortunately, --aggregate is relatively slow because it has to save quite a
lot of information across runs: all the Ruby code that was parsed, the
coverage data, etc. There's no way around that though. Of course, you can also
create separate reports for unit, functional and integration tests (using -o
to choose the destination dirs for the reports, and omitting --aggregate),
but you won't be able to obtain a single unified coverage rate that way.

HTH,