[test-improver] Improve tests for strutil.RandomHex

[github-actions]

File Analyzed

• Test File: internal/strutil/random_hex_test.go
• Package: internal/strutil
• Lines of Code: 51 → 92

Improvements Made

1. Better Testing Patterns

• ✅ Extended table-driven test with wantErr bool field to cover both success and error paths in a single unified table
• ✅ Added descriptive test names for all new cases
• ✅ Tests use require.Error / assert.Empty for error cases and require.NoError / assert.Len for success cases

2. Increased Coverage

• ✅ Added n=0 edge case — zero bytes produces empty string with no error
• ✅ Added n=-1 and n=-100 test cases — exercises the if n < 0 error branch that was previously untested
• ✅ Added TestRandomHex_ErrorMessageContainsSize — verifies the error message includes the invalid size value
• ✅ Added TestRandomHex_IsValidHex — verifies the output is a valid hex-encoded string and that hex.DecodeString round-trips back to n bytes

Previously uncovered code paths:

if n < 0 {
    return "", fmt.Errorf("failed to generate random bytes: negative size %d", n)
}

This branch was completely untested. The n==0 edge case (producing an empty string) was also not exercised.

3. Cleaner & More Stable Tests

• ✅ Single table covers all n input variants (including errors), reducing the number of separately named test functions
• ✅ New standalone tests focus on orthogonal properties (error message content, hex encoding validity)
• ✅ Existing TestRandomHex_Uniqueness test preserved unchanged

Why These Changes?

RandomHex is a foundational utility used for generating API keys and session IDs. Its error branch for negative inputs was entirely untested — any regression there (e.g., panic instead of error, wrong error message) would go undetected. The zero-byte case is a valid boundary that deserves explicit documentation as a test. The hex-encoding validity test provides a round-trip guarantee, ensuring future changes to the encoding format are caught early.

---

Generated by Test Improver Workflow
Focuses on better patterns, increased coverage, and more stable tests

Generated by Test Improver · ● 4.9M · ◷