Clean up some low-hanging warnings in test suite #911

All 1 042 tests pass, 6 skipped in 29m 46s

22 files ±0 22 suites ±0 29m 46s ⏱️ -37s
1 048 tests ±0 1 042 ✅ ±0 6 💤 ±0 0 ❌ ±0
10 420 runs ±0 10 357 ✅ ±0 63 💤 ±0 0 ❌ ±0

Results for commit bbf31ca. ± Comparison against earlier commit 7cc01e8.