Test runner output differs from real output

Information:

• Prism version: 1.29.0

Description
I am trying to add support for Adventure Game Studio script syntax and have the highlighter working, but I am unable to add tests because the test runner token stream appears to be different to the real token stream.

Example
Build the fork at https://github.com/adventuregamestudio/prism/tree/ags as normal (the only changes in the fork are the addition of two languages).

Using the language "agsdialog" with this content:

@S
@1

...will produce this output within the test page:

<span class="token line"><span class="token dialog-index variable">@S</span></span>
<span class="token line"><span class="token dialog-index variable">@1</span></span>

Using the following HTML based test through the test runner:

@S
@1

----------------------------------------------------

<span class="token line"><span class="token dialog-index variable">@S</span></span>
<span class="token line"><span class="token dialog-index variable">@1</span></span>

----------------------------------------------------

Dialog indices.

...will produce this output from the test:

<span class="token line"><span class="token dialog-index variable">@S</span></span>
<span class="token line"></span>
<span class="token line"></span>
<span class="token line"></span>
<span class="token line"></span>
<span class="token line"></span>
@1

To be very clear, I am only seeing problems within the test runner. Outside of the test runner the tokens and output are as expected, and this is visually confirmed on the test page:

Reproduce the mismatch in the test runner using the agsdialog language and the @S/@1 input, then compare it with the output shown on the test page. Trace how the runner parses the HTML-based expected output; done means both tokens are preserved and the runner output matches the real highlighted output.