Drupal 7 Module Development

Creating Your First Module
You might notice that the function began $this->assertEqual() which is a
member method, but one that we did not define. ($this, for those new to PHP's
OOP, is a shorthand way of referring to the present object.) The parent class,
DrupalWebTestCase, provides a dozen or so assertion methods that make writing
tests easier. Many of these will come up in subsequent chapters, but in our tests we
use two:
• $this->assertEqual(): Assert that the first (known) value equals the
second (tested) value.
• $this->assertTrue(): Assert that the given value evaluates to TRUE.
While the first assertion validates that we defined one block in our block info
hook implementation, the second assertion verifies that the name of this block is
list_modules. Thus, by the time this test has run, we can be sure that our info
hook is returning information about our single block.
The next test verifies that the first_block_view() function is returning the
correct information.
public function testBlockView() {
$data = module_invoke('first', 'block_view',
'list_modules');
}
$this->assertTrue(is_array($data),
t('Block returns renderable array.'));
$this->assertEqual(t('Enabled Modules'), $data['subject'],
t('Subject is set'));
Again, module_invoke() is used to execute a hook—this time the block view hook
implementation. And again we perform two assertions. First, we check to make sure
that an array is returned from first_block_view(). Second, we verify that the title
is Enabled Modules, as we expect.
We could go on and add another assertion—something that makes sure that the
$data['content'] field has the expected data in it. But that information is a little
volatile. We are not positive about which other modules will be enabled, and testing
against that would be injecting an external dependency into our test, which is
considered bad form.
At this point, we have defined one test case, FirstTestCase, which defines four
methods. Two of those methods are tests, each containing two assertions. So when
we run the test, we should see one test case, two tests, and two assertions for
each test.
[ 58 ]