Code coverage is important for the success of any project including PHP. When code coverage reaches 100%, it'll mean that every piece of code within the PHP sources will be executed while running the tests. This helps determine if behaviour changes so essentially it helps prevent bugs from being introduced into PHP.

gcc >= 3.4 with gcov. Your local setup should also include lcov that is available here:

• http://sourceforge.net/project/showfiles.php?group_id=3382&package_id=80148

Once installed, compile PHP with GCOV support using --enable-gcov so for example:

  # wget foo.com/phpsrc.tar.gz
  # tar xfvz phpsrc.tar.gz
  # cd phpsrc
  # ./configure --with-foo --with-bar --enable-gcov
  # make

In summary: Install lcov, compile PHP with --enable-gcov, and now you're ready.

• Go to gcov.php.net
• Choose a branch, then 'coverage'
• Will go into some detail on what it means

• Go to http://qa.php.net/...

• Yes...

• Locate a file with a percentage < 100%
• Use the legend to determine uncovered code
• Write code that will execute it

• make lcov
• view lcov_html/index.html
• make a new test
• re-run lcov:
  • make lcov TESTS=ext/foo/tests/bar.phpt
  • Note: The TESTS var is to speed-up the process, as it will only run the specific test(s)

You can submit tests to the development mailing list @ internals@lists.php.net

Short answer: You don't. Long answer: valgrind can be used to detect if some test triggers a memory-related bug in PHP. Although running the test suite with valgrind is a plus, but it takes ages. You can submit tests without running valgrind, because the http://gcov.php.net project will do that for you.

Just untar it and run make install.