Using mixed case in test names causes HTML replacements tags not to be replaced

[vtsatskin]

Doing something like this:

<?php
$myTest = new phpab('myTest');
$myTest->add_variation('my_variation', "I'm a variation!");
?>

{phpab myTest}
I'm a control!
{/phpab myTest}

Causes the output not to be replaced:

{phpab myTest}
I'm a control!
{/phpab myTest}

However, the output is correct if the replacement tag is changed to lowercase:

<?php
$myTest = new phpab('myTest');
$myTest->add_variation('my_variation', "I'm a variation!");
?>

{phpab mytest}
I'm a control!
{/phpab mytest}

Which produces either output:

I'm a control!

or

I'm a variation!