Reaching 100% Code Coverage with PHPUnit

Question

I've been in the process of creating a test suite for a project, and while I realize getting 100% coverage isn't the metric one should strive to, there is a strange bit in the code coverage report to which I would like some clarification.

See screenshot:

Because the last line of the method being tested is a return, the final line (which is just a closing bracket) shows up as never being executed, and as a consequence the whole method is flagged as not executed in the overview. (Either that, or I'm not reading the report correctly.)

The complete method:

static public function &getDomain($domain = null) {
    $domain = $domain ?: self::domain();

    if (! array_key_exists($domain, self::$domains)) {
        self::$domains[$domain] = new Config();
    }

    return self::$domains[$domain];
}

Is there a reason for this, or is it a glitch?

(Yes, I read through How to get 100% Code Coverage with PHPUnit, different case although similar.)

Edit:

Trudging on through the report, I noticed the same is true for a switch statement elsewhere in the code. So this behaviour is at least to some extent consistent, but baffling to me none the less.

Edit2:

I'm running on: PHPUnit 3.6.7, PHP 5.4.0RC5, XDebug 2.2.0-dev on a OS X

Answer 1

First off: 100% code coverage is a great metric to strive for. It's just not always achievable with a sane amount of effort and it's not always important to do so :)

The issue comes from xDebug telling PHPUnit that this line is executable but not covered.

For simple cases xDebug can tell that the line is NOT reachable so you get 100% code coverage there.

See the simple example below.

---

2nd Update

The issue is now fixed xDebug bugtracker so building a new version of xDebug will solve those issues :)

Update (see below for issues with php 5.3.x)

Since you are running PHP 5.4 and the DEV version of xDebug I've installed those and tested it. I run into the same issues as you with the same output you've commented on.

I'm not a 100% sure if the issue comes from php-code-coverage (the phpunit module) for xDebug. It might also be an issue with xDebug dev.

I've filed a bug with php-code-coverage and we'll figure out where the issue comes from.

---

For PHP 5.3.x issues:

For more complex cases this CAN fail.

For the code you showed all I can say is that "It works for me" (complex sample below).

Maybe update xDebug and PHPUnit Versions and try again.

I've seen it fail with current versions but it depends on how the whole class looks sometimes.

Removing ?: operators and other single-line multi-statement things might also help out.

There is ongoing refactoring in xDebug to avoid more of those cases as far as I'm aware. xDebug once wants to be able to provide "statement coverage" and that should fix a lot of those cases. For now there is not much one can do here

While //@codeCoverageIgnoreStart and //@codeCoverageIgnoreEnd will get this line "covered" it looks really ugly and is usually doing more bad than good.

For another case where this happens see the question and answers from:

what-to-do-when-project-coding-standards-conflicts-with-unit-test-code-coverage

---

Simple example:

<?php
class FooTest extends PHPUnit_Framework_TestCase {
    public function testBar() {
        $x = new Foo();
        $this->assertSame(1, $x->bar());
    }
}

<?php
class Foo {
    public function bar() {
        return 1;
    }
}

produces:

phpunit --coverage-text mep.php 
PHPUnit 3.6.7 by Sebastian Bergmann.

.

Time: 0 seconds, Memory: 3.50Mb

OK (1 test, 1 assertion)

Generating textual code coverage report, this may take a moment.

Code Coverage Report 
  2012-01-10 15:54:56

 Summary: 
  Classes: 100.00% (2/2)
  Methods: 100.00% (1/1)
  Lines:   100.00% (1/1)

Foo
  Methods: 100.00% ( 1/ 1)   Lines: 100.00% (  1/  1)

Complex example:

<?php

require __DIR__ . '/foo.php';

class FooTest extends PHPUnit_Framework_TestCase {

    public function testBar() {
        $this->assertSame('b', Foo::getDomain('a'));
        $this->assertInstanceOf('Config', Foo::getDomain('foo'));
    }
}

<?php

class Foo {
    static $domains = array('a' => 'b');

    static public function &getDomain($domain = null) {
        $domain = $domain ?: self::domain();
        if (! array_key_exists($domain, self::$domains)) {
            self::$domains[$domain] = new Config();
        }
        return self::$domains[$domain];
    }
}

class Config {}

produces:

PHPUnit 3.6.7 by Sebastian Bergmann.

.

Time: 0 seconds, Memory: 3.50Mb

OK (1 test, 2 assertions)

Generating textual code coverage report, this may take a moment.

Code Coverage Report 
  2012-01-10 15:55:55

 Summary: 
  Classes: 100.00% (2/2)
  Methods: 100.00% (1/1)
  Lines:   100.00% (5/5)

Foo
  Methods: 100.00% ( 1/ 1)   Lines: 100.00% (  5/  5)