fix(failed_tests_file): correctly iterate testsFailed dict

[kei-nan]

Bug

self.testsFailed is a dict of {test_name: [failures]} (built via setdefault(name, []).extend(...) in addFailureToTest). The --failed-tests-file writer in RLTest/__main__.py iterates it as:

for test, _ in self.testsFailed:
    file.write(test.split(' ')[0] + "\n")

Iterating a dict yields keys (strings). Python then tries to unpack each key into (test, _) — which fails for any test name longer than two characters:

File "…/RLTest/__main__.py", line 1070, in execute
    for test, _ in self.testsFailed:
        ^^^^^^^
ValueError: too many values to unpack (expected 2)

This silently breaks the --failed-tests-file (-F) feature whenever a run actually has failures: the writer aborts before producing the file, RLTest exits with the unhandled exception, and any downstream tooling that depends on the file sees no output.

Repro

python -m RLTest --module path/to/module.so --failed-tests-file /tmp/failed.txt --test some_failing_test.py

Crashes with the traceback above; /tmp/failed.txt is empty or missing.

Fix

Iterate keys directly. The value side wasn't used (just _), so this is the smallest correct change:

for test in self.testsFailed:
    file.write(test.split(' ')[0] + "\n")

Why this hasn't been caught

The buggy code only runs when self.testsFailed is non-empty AND --failed-tests-file is set. Most CI pipelines that use -F only see green runs, so the path stays dormant. Surfaced from the RediSearch flaky-test DB work (RediSearch/RediSearch#9869) when failures finally hit the writer.

Test plan

• Run a known-failing test with --failed-tests-file=/tmp/f.txt → confirm /tmp/f.txt lists the failed test names instead of crashing
• Run a passing test with the same flag → confirm an empty file is created (matches existing behavior of the else branch)

[codecov-commenter]

⚠️ Please install the to ensure uploads and comments are reliably processed by Codecov.

Codecov Report

❌ Patch coverage is 0% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 34.83%. Comparing base (02cfbb9) to head (5806e03).
⚠️ Report is 12 commits behind head on master.

Files with missing lines	Patch %	Lines
RLTest/__main__.py	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #251      +/-   ##
==========================================
+ Coverage   32.46%   34.83%   +2.37%     
==========================================
  Files          17       18       +1     
  Lines        2597     2733     +136     
==========================================
+ Hits          843      952     +109     
- Misses       1754     1781      +27     

Flag	Coverage Δ
unittests	34.83% <0.00%> (+2.37%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

Addressed comment - got approval from Guy
Would like to merge this as soon as possible.