[BE] refactor: MockData 설정 로직 리팩터링 및 테스트 속도 개선 (#839) #751

All 661 tests pass in 24s

199 files +3 199 suites +3 24s ⏱️ -1s
661 tests +6 661 ✅ +6 0 💤 ±0 0 ❌ ±0
674 runs +6 674 ✅ +6 0 💤 ±0 0 ❌ ±0

Results for commit eb75e63. ± Comparison against earlier commit 541c543.