Convert mail.test to PSR-0

Classes converted.

I have also attached the concatenated output of git blame -C on the new files, showing that most of the code originated in the old file. Best viewed without automatic linewrapping, without Dreditor or zoomed out, to get an overview.

+++ b/core/modules/system/lib/Drupal/system/Tests/Mail/Test.phpundefined
@@ -0,0 +1,92 @@
+    variable_set('mail_system', array('default-system' => 'MailTestCase'));

Meh ... should have renamed this to the new class name.

I know it's bad to repeat "Mail" in the name of the classes. But the class "Test" looks even worse, it doesn't say what the class does.

options:
1) Find a better name for the class
2) Just name it MailTest, like we did with the tracker module and others. At least this tells us that we are testing mail functionality

Html to text conversion doesn't rely on mailing => Does not nescessarily belong into the Mail namespace => Now we have two classes, that don't qualify each for an own namespace => Just move them both to common. Also now we don't have Mail/Test or Mail/MailTest, but Common/MailTest instead.

Good to go!

Thanks.

As sun suggested, here's also a diff with lower thresholds for rename detection.

Committed to 8.x. Thanks!

Uh oh. I just realized that this commit was not done correctly. I used patch -p1 to apply the patch, but it did not do the rename properly. So I had to do a second commit. I backed out the patch above with patch -p1 -R, and then used git apply to re-apply. The net result was:
rename core/modules/system/{tests/mail.test => lib/Drupal/system/Tests/Common/HtmlToTextTest.php}

So, now it's actually fixed. Sorry about that!