test: added 3 new test cases in the new describe named edge case

[Vansh1419]

What changed and why

Added 3 unit test in test/baseline.test.ts under new describe named edge cases

Closes #1030

Before

Test Suites: 6 failed, 108 passed, 114 total
Tests:       29 failed, 1417 passed, 1446 total
Snapshots:   0 total
Time:        3.115 s, estimated 4 s

After

Test Suites: 6 failed, 108 passed, 114 total
Tests:       29 failed, 1420 passed, 1449 total
Snapshots:   0 total
Time:        2.906 s, estimated 3 s

[sonukapoor]

Good edge case coverage - all-new, partial match, and version-mismatch are exactly the three scenarios worth testing here. The Baseline type import was missing too, nice catch. Merging.

[sonukapoor]

Merged - thank you @Vansh1419!