diff --git tests/phpunit/includes/factory.php tests/phpunit/includes/factory.php
index e9c4743..d5f46d8 100644
--- tests/phpunit/includes/factory.php
+++ tests/phpunit/includes/factory.php
@@ -1,5 +1,10 @@
 <?php
 
+/**
+ * A factory for making WordPress data with a cross-object type API.
+ *
+ * Tests should use this factory to generate test fixtures.
+ */
 class WP_UnitTest_Factory {
 
 	/**
@@ -296,6 +301,9 @@ class WP_UnitTest_Factory_For_Term extends WP_UnitTest_Factory_For_Thing {
 	}
 }
 
+/**
+ * An abstract class that serves as a basis for all WordPress object-type factory classes.
+ */
 abstract class WP_UnitTest_Factory_For_Thing {
 
 	var $default_generation_definitions;
diff --git tests/phpunit/includes/testcase.php tests/phpunit/includes/testcase.php
index a468deb..71b8ed4 100644
--- tests/phpunit/includes/testcase.php
+++ tests/phpunit/includes/testcase.php
@@ -3,6 +3,15 @@
 require_once dirname( __FILE__ ) . '/factory.php';
 require_once dirname( __FILE__ ) . '/trac.php';
 
+/**
+ * Defines a basic fixture to run multiple tests.
+ *
+ * Resets the state of the WordPress installation before and after every test.
+ *
+ * Includes utility functions and assertions useful for testing WordPress.
+ *
+ * All WordPress unit tests should inherit from this class.
+ */
 class WP_UnitTestCase extends PHPUnit_Framework_TestCase {
 
 	protected static $forced_tickets = array();
@@ -123,6 +132,9 @@ class WP_UnitTestCase extends PHPUnit_Framework_TestCase {
 		$this->expectedDeprecated();
 	}
 
+	/**
+	 * After a test method runs, reset any state in WordPress the test method might have changed.
+	 */
 	function tearDown() {
 		global $wpdb, $wp_query, $wp, $post;
 		$wpdb->query( 'ROLLBACK' );