test: prevent virtualenvwrapper temp directory collisions (Fixes #498)

[Karthik Nadig (karthiknadig)]

Summary

• retain timestamp and process ID uniqueness for virtualenvwrapper test directories
• add a process-local atomic sequence so parallel tests cannot collide at coarse clock resolution
• preserve existing explicit cleanup behavior

Validation

• 20 consecutive cargo test -p pet-virtualenvwrapper --lib --quiet runs
• cargo test -p pet-virtualenvwrapper --lib
• .\scripts\rust-precommit.ps1

Fixes #498

[github-actions]

Test Coverage Report (Linux)

Metric	Value
Current Coverage	80.6%
Base Branch Coverage	80.5%
Delta	.1% ✅

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Coverage increased! Great work!

[github-actions]

Performance Report (macOS)

Metric	PR (P50)	PR (P95)	Baseline (P50)	Delta
Server Startup	63ms	2330ms	69ms	-6ms
Full Refresh	98ms	30290ms	118ms	-20ms

Results based on 10 iterations. P50 = median, P95 = 95th percentile.

---

Legend

• 🚀 Significant speedup (>100ms faster)
• ✅ Faster than baseline
• ➖ No significant change
• 🔺 Slower than baseline (>100ms)
• ⚠️ Significant slowdown (>500ms)

[github-actions]

Test Coverage Report (Windows)

Metric	Value
Current Coverage	77.52%
Base Branch Coverage	77.31%
Delta	0.21% ✅

---

Coverage increased! Great work!

[github-actions]

Performance Report (Windows) ✅

Metric	PR (P50)	PR (P95)	Baseline (P50)	Delta	Change
Server Startup	8ms	12ms	9ms	-1ms	-11.1%
Full Refresh	159ms	1184ms	164ms	-5ms	-3%

Results based on 10 iterations. P50 = median, P95 = 95th percentile.

---

Legend

• 🚀 Significant speedup (>100ms faster)
• ✅ Faster than baseline
• ➖ No significant change
• 🔺 Slower than baseline (>100ms)
• ⚠️ Significant slowdown (>500ms)

[github-actions]

Performance Report (Linux) ✅

Metric	PR (P50)	PR (P95)	Baseline (P50)	Delta	Change
Server Startup	1ms	1ms	1ms	0ms	0%
Full Refresh	48ms	331ms	55ms	-7ms	-10.0%

Results based on 10 iterations. P50 = median, P95 = 95th percentile.

---

Legend

• 🚀 Significant speedup (>100ms faster)
• ✅ Faster than baseline
• ➖ No significant change
• 🔺 Slower than baseline (>100ms)
• ⚠️ Significant slowdown (>500ms)

[Copilot]

Pull request overview

This PR hardens the pet-virtualenvwrapper test suite against intermittent failures caused by temp directory name collisions during parallel execution. It updates the test-only directory naming scheme to remain unique even when the system clock has coarse resolution, while keeping the existing explicit cleanup approach.

Changes:

• Add a process-local AtomicUsize sequence to guarantee unique test directory names under parallelism.
• Preserve process ID and timestamp components in the temp directory name for additional uniqueness.
• Keep existing remove_dir_all-based cleanup behavior in tests.

Show a summary per file

File	Description
crates/pet-virtualenvwrapper/src/environments.rs	Updates test helper create_test_dir() to include an atomic sequence ID to prevent temp directory collisions during parallel tests.

Review details

• Files reviewed: 1/1 changed files
• Comments generated: 0
• Review effort level: Lite