test: keep RPC coverage dir under runner tmpdir

[thepastaclaw]

Summary

Motivation

test_runner.py --coverage currently creates the shared RPC coverage
directory directly under the system temp directory via
tempfile.mkdtemp(prefix="coverage").

In CI this can leave the coverage lifecycle outside the runner-owned temp tree,
which matches #7273 where /tmp/coverage* disappeared while
coverage-enabled functional tests were still running.

Changes

• Pass the runner tmpdir into RPCCoverage.
• Create the shared RPC coverage directory under that runner-managed temp tree.

Validation

• python3 -m py_compile test/functional/test_runner.py
• Smoke-tested RPCCoverage(tmpdir) creation/cleanup with a temporary parent
  directory.
• Pre-PR code review gate: ship.

Fixes #7273.

[thepastaclaw]

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⚙️ Run configuration

Configuration used: Repository UI

Review profile: CHILL

Plan: Pro

Run ID: 56fe761c-565d-43db-833c-727577063493

📥 Commits

Reviewing files that changed from the base of the PR and between 4a0fd85 and 73d1bd5.

📒 Files selected for processing (1)

• test/functional/test_runner.py

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Walkthrough

The change modifies the RPCCoverage class to accept a tmpdir parameter in its constructor. The run_tests() function now passes the test's temporary directory to RPCCoverage during initialization, causing the coverage working directory to be created as a subdirectory of tmpdir rather than in a default system location.

Estimated code review effort

🎯 1 (Trivial) | ⏱️ ~3 minutes

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 33.33% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title accurately summarizes the main change: moving RPC coverage directory creation under the runner-managed tmpdir.
Description check	✅ Passed	The description is well-related to the changeset, explaining the motivation (coverage dir lifecycle issues in CI), changes made, and validation performed.
Linked Issues check	✅ Passed	The code changes directly address the linked issue #7273 by ensuring the shared RPC coverage directory is created under the runner-managed tmpdir, tying its lifecycle to the runner.
Out of Scope Changes check	✅ Passed	All changes are in-scope, modifying only RPCCoverage.init to accept tmpdir and creating the coverage directory under it, directly addressing the linked issue.

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🧪 Generate unit tests (beta)

• Create PR with unit tests

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[thepastaclaw]

✅ Review complete (commit 62452f2)

[thepastaclaw]

Code Review

Small, well-scoped fix moving the shared RPC coverage directory under the runner-managed tmpdir (created at test_runner.py:479) instead of the system tempdir. Lifecycle is correct: coverage.cleanup() at line 668 removes the subdirectory before the empty-tmpdir check at line 673, and RPCCoverage has no other callers. Both agents independently verified no regressions; nothing to flag.

Reviewed commit: 73d1bd5

[thepastaclaw]

Code Review

Small, well-scoped change: RPCCoverage's coverage dir is now created under the runner-managed tmpdir. Verified lifecycle is correct — tmpdir is created (line 479) before RPCCoverage(tmpdir) is constructed (line 601), and coverage.cleanup() (line 668) runs before the empty-tmpdir rmdir check (line 673). RPCCoverage has only this one call site, so the constructor signature change is safe.

Reviewed commit: 62452f2

[thepastaclaw]

Closing this as irrelevant/too speculative. The code path is inherited from upstream Bitcoin Core, and I don't have a Dash-specific reason strong enough to justify diverging from that backported test_runner behavior for a one-off coverage tempdir failure.