QA:CodeCoverage: Difference between revisions

== <FONT COLOR=GREEN>What is the progress so far!!</FONT> ==

Results would be discussed in a separate section.

We have generated a lot of trend diagrams to study the interaction between code coverage data for a given file and the number of bug fixes went into the file; code coverage Vs the number of times the file is modified and file churn Vs bug fix rate.  

Results would be discussed below.

The plan is to observe the temporal changes in the above trends as we fix more bugs as well as develop new test cases.

This is what is planned for the immediate future

* We are going to identify top 3 modules that needs further analysis

* We will identify at least 6 files in each of those modules that have active churn but not good coverage

* We will work with DEV and QA to come up with scenarios to improve coverage on those files

== <FONT COLOR=GREEN>Results and Findings </FONT> ==

For the full report to do your own study, please use the following URL

For those who just want to have a peek, here are some screen shots.

http://people.mozilla.org/~mnandigama/images/Picture%202.png

'''This is important ''': We have done a component/module by component/module code coverage Vs Bugs fix analysis.

* In a happy path case, all files should have 100% code coverage

* In a normal path case, all files that have high rate of bugs fixed in them, should have '''HIGH''' code coverage since there are the most active files in terms of change.

* Files that have no change since a long time can have either '''HIGH''' or '''LOW''' coverage in our first iteration since they are not undergoing any change so far.

For a sample module, '''JavaScript Engine''' the code coverage Vs Bug fixes looks like this.

http://people.mozilla.org/~mnandigama/images/covBugs.png

In a bubble chart format , the same can be visualized as follows

http://people.mozilla.org/~mnandigama/images/sample3.png

The '''bigger''' the bubble, the higher it should be and all bubbles should ideally bubble up.

== <FONT COLOR=GREEN>How to instrument the Mozilla Firefox Browser </FONT> ==

=== Build config ===

Create a .mozconfig-gold file in your home directory with the following statements

For more detailed build options and prerequisites, please visit the following URL

https://developer.mozilla.org/en/Configuring_Build_Options

Checkout the source code from the mozilla-central code repository.

TIP: Save the above commands into a file named ‘startover’ and make it executable.

 

 

Change Directory to ~/mozcentral-dbg/_tests/testing/mochitest and execute the following command.

 

 

In order to run jstests, please go to ~/src/js/tests and execute the following commands

=== Gather the data ===

Now, come back into your home directory and execute the following command

The lcov tool will go through the entire build directory and generates an app.info file in your home directory

 

 

Then, execute the following command

If by any chance the above command fails to complete, use the following option.

 

 

HINT: Look at the advanced tweaks section on how to modify, geninfo, genhtml scripts in order to generate full code coverage reports.

 

 

 

Tools -> JSCoverage -> View Coverage loads the jscoverage.html file

Tools -> JSCoverage -> Store Coverage saves the coverage data into a directory named "./jscoverage-report.

== <FONT COLOR=GREEN>Scripts and Works around required </FONT> ==

=== Change to the mozilla code ===

The work around to address this problem is as follows:

Execute the usual build command 'make -f client.mk build'

Please make sure that you have all the build dependencies installed properly before attempting the build.

 

You'll need [http://ltp.sourceforge.net/coverage/lcov.php lcov].  

on os X the bin/install.sh needs to be modified on the last line there is a install -D remove the -D switch as it's not supported on OS X.

   Esc -> : -> %s/die/print/g -> Enter

   Esc -> : -> %s/die/print/g -> Enter

Code coverage for the Javascript part of the Firefox can be done in multiple ways. But using JSCoverage as the tool seemed to be the best way as JSCoverage is an open source tool.

I wish to fully acknowledge the great help Ed Kelly , who maintains the JSCoverage tool , provided in this instrumentation exercise. Ed was very generous in spending cycles to provide enhancements to the JSCoverage tool to meet Firefox instrumentation requirements.

So ... here is how to instrument the javascript portion of Firefox.

 

 

 

To compile, run bootstrap.sh (requires Automake and Autoconf):

 

 

The following enhancements are present in our own build with latest revision.

1. Instrumenting symbolic links in the case where the destination is a regular file.  

For those who are curious, JSCoverage does not instrument javascript files that are symbolically referenced.

2. It copies file permissions (so that executable files stay executable).

3. It has the --mozilla option to copy the jscoverage.html file directly into Firefox's chrome.  

The --mozilla option automatically sets the JavaScript version to 180,so it is not necessary to use both --mozilla and --js-version at the same time.

NOTE: --js-version=180 would allow instrumenting the symbolic links

 

HINT: If you find a foobar.js file failing in the javascript instrumentation exercise, please add it to the no-instrument list using the following syntax --no-instrument=/path/to/foobar.js

 

It seems that it is necessary to use --no-instrument on the entire defaults and prefs directories because the preferences .js files should not contain arbitrary JavaScript.

See http://www.xulplanet.com/tutorials/xulqa/q_prefs.html or https://bugzilla.mozilla.org/show_bug.cgi?id=440777 for details.