diff --git a/core/modules/simpletest/simpletest.module b/core/modules/simpletest/simpletest.module
index 82d5faf..8cf5623 100644
--- a/core/modules/simpletest/simpletest.module
+++ b/core/modules/simpletest/simpletest.module
@@ -756,7 +756,7 @@ function simpletest_phpunit_xml_to_rows($test_id, $phpunit_xml_file) {
   $records = array();
   foreach ($xml->testsuite as $testsuite) {
     foreach ($testsuite as $suite) {
-      // The file element won't be on testcase objects created with 
+      // The file element won't be on testcase objects created with
       // @dataProvider, so just use the one from the test suite at this level
       // because it should be the same.
       $file = (string)$suite->attributes()->file;
@@ -770,10 +770,21 @@ function simpletest_phpunit_xml_to_rows($test_id, $phpunit_xml_file) {
   return $records;
 }
 
-function simpletest_phpunit_find_testcases($testsuite) {
+/**
+ * Find all testcases recursively from a testsuite list.
+ *
+ * @param array $suite
+ *   The list of testcases contained in the PHPUnit XML.
+ *
+ * @return array
+ *   A list of all testcases.
+ */
+function simpletest_phpunit_find_testcases($suite) {
   $testcases = array();
 
   foreach ($suite as $testcase) {
+    // Beside from being 'testcases', it could be also a group of testcases.
+    // This happens if you use a data provider in the phpunit tests.
     if ($testcase->getName() === 'testcase') {
       $testcases[] = $testcase;
     }
@@ -786,7 +797,19 @@ function simpletest_phpunit_find_testcases($testsuite) {
   return $testcases;
 }
 
-function simpletest_phpunit_testcase_to_row($test_id, $testcase, $file) {
+/**
+ * Converts a PHPUnit testcase result to a simpletest result row.
+ *
+ * @param int $test_id
+ *   The current test ID.
+ * @param \SimpleXMLElement $testcase
+ *   The PHPUnit testcase represented as xml element.
+ * @param string $file
+ *   The path to test file, which was executed.
+ * @return array
+ *   An array containg the simpletest result row.
+ */
+function simpletest_phpunit_testcase_to_row($test_id, \SimpleXMLElement $testcase, $file) {
   $message = '';
   $pass = TRUE;
   if ($testcase->failure) {