Source code, additional information, screenshots… available at
http://eigenclass.org/hiki/rcov
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 code coverage tool for Ruby. It is commonly used for viewing overall test coverage of target code. It features:
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_for_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/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