Improve PHPUnit failure output by including fixture names

[ghostwriter]

Problem

When a test fails using a data provider, PHPUnit currently displays only numeric indexes (for example #0, #1, etc.). This makes it difficult to identify which specific fixture caused the failure.

Users must manually cross-reference the index with the data provider, which is confusing and time-consuming, especially when there are many fixtures.

Solution

This patch updates the output to include the fixture name instead of just the numeric index.

This allows users to immediately identify the failing test case without additional lookup.

Benefits

• Faster debugging
• Clearer failure output
• Eliminates manual index-to-fixture mapping
• Improves developer experience when working with large datasets

Before

Numeric index only, no context:

After

Fixture name is displayed, providing clear context:

Summary

This change makes PHPUnit output more informative and significantly reduces the time required to identify failing fixtures.

[TomasVotruba]

This disables a way to quickly run specific test fixture like:

phpunit SomeTest.php --filter test#2

Instead, full file path has to typed instead:

phpunit SomeTest.php --filter test#some_specific_file_path.php

This becomes even more cumbersome, when file paths have similar starts:

phpunit SomeTest.php --filter test#some_specific_file_path.php
phpunit SomeTest.php --filter test#some_specific_file_path_with_edge_case.php

Saying that, I want to keep the #X approach, as 1 char is required to run the test.

[ghostwriter]

I believe we could have prefixed each fixture name with a 1 character numeric index, to enable and preserve both features, but I'll accept your decision.

Thanks for your time.