Test libraries caching

Hm, not sure whether this test makes sense. The following would make more sense to me, but I'm not sure whether it is possible to test, and whether it's worth the effort:

libraries_load('example');
$this->assertCacheMiss();
libraries_load('example');
$this->assertCacheHit();

Otherwise, we're merely testing core's Cache API and not really our own caching mechanism.

But I somewhat doubt that these (pseudo) assertCacheMiss() and assertCacheHit() assertions are possible without introducing a really large chunk of testing code that might be a hack even.

Though, perhaps set a variable and just simply conditionally output a message in hook_libraries_info() of the testing module -- which should then only be triggered on a cache miss, if I get this right?

Putting it into one of the cached callbacks sounds good. By wrapping it into a condition if (variable_get('libraries_test_cache', FALSE), it will only be output and affect this test.

+++ b/tests/libraries_test.module
@@ -414,34 +421,34 @@ function _libraries_test_callback(&$library, $version, $variant, $group) {
+  foreach ($items as &$item) {
+    $item += array(
+      'page callback' => '_libraries_test_load',
+      'access callback' => TRUE,
+    );
+  }

Let's define

$base = array(...);

and + that into the others:

$items[...] = $base + array(...);

Aside from that, this looks good to me.