--- name: bug-fix-testing-f25e1b5009fd description: Patterns for creating tests that verify bug fixes and prevent regressions. Use when writing tests for bug fixes, creating regression tests, or verifying fix effectiveness. --- # Bug Fix Testing This skill provides testing patterns specifically designed for bug fix verification. ## When to Use - Creating regression tests for a specific bug fix - Writing tests that prove a bug is fixed - Verifying fix effectiveness - Adding edge case coverage related to a bug ## Test Types Required for Bug Fixes ### 1. Regression Test (Required) Proves the specific bug is fixed and prevents recurrence: ```typescript describe('[TICKET-ID]: Brief bug description', () => { it('should not exhibit the bug behavior', () => { // Arrange: Set up the exact condition that triggered the bug // Use steps from bug-context.md "Steps to Reproduce" // Act: Trigger the scenario that caused the bug // Assert: Verify correct behavior (not bug behavior) }); }); ``` **Key Principle**: This test should FAIL on the old code and PASS with the fix. ### 2. Edge Case Tests (Recommended) Cover related scenarios identified in the RCA: ```typescript it('should handle [edge case from RCA]', () => { // Test boundary conditions and related scenarios }); ``` ### 3. Integration Test (If Applicable) Verify the fix works in realistic context: ```typescript it('should work correctly in [real-world scenario]', () => { // End-to-end verification }); ``` ## Test Naming Convention Format: `[TICKET-ID]_[Component]_[Scenario]_[ExpectedBehavior]` **Examples:** - `EMS1234_UserAuth_ExpiredToken_ShouldRedirectToLogin` - `TMSPROV567_DataSync_ConcurrentUpdates_ShouldNotLoseData` - `TEST001_PromptStructure_MixedPatterns_ShouldBeConsistent` ## Verification Approach ### Proving Test Effectiveness Since we cannot automatically run tests on old code: 1. **With fix**: Run the test → Should PASS ✅ 2. **Optional verification**: - Temporarily revert the fix - Run the test → Should FAIL ❌ - Re-apply the fix ### Test Quality Checklist - [ ] Test uses exact scenario from bug report - [ ] Test would fail without the fix - [ ] Test is deterministic (no flakiness) - [ ] Test is isolated (no external dependencies) - [ ] Test has clear assertion messages - [ ] Test covers the root cause, not just symptoms ## Language-Specific Templates ### TypeScript/JavaScript (Jest/Vitest) ```typescript import { describe, it, expect, beforeEach } from 'vitest'; // or 'jest' describe('[TICKET-ID]: [Bug title]', () => { // Setup that recreates bug conditions beforeEach(() => { // Reset state }); it('should not [bug behavior]', () => { // Arrange const input = /* condition that triggered bug */; // Act const result = functionUnderTest(input); // Assert expect(result).not.toBe(/* bug behavior */); expect(result).toBe(/* correct behavior */); }); it('should handle [edge case]', () => { // Additional coverage }); }); ``` ### Python (pytest) ```python import pytest class TestTicketID: """Tests for bug fix: [TICKET-ID] - [Bug title]""" def test_should_not_exhibit_bug_behavior(self): """Regression test: ensures bug does not recur.""" # Arrange input_data = ... # condition that triggered bug # Act result = function_under_test(input_data) # Assert assert result != "bug behavior" assert result == "correct behavior" def test_should_handle_edge_case(self): """Edge case from RCA analysis.""" # Additional coverage pass ``` ### C# (xUnit/NUnit) ```csharp public class TicketIdTests { /// /// Regression test for TICKET-ID: Bug title /// [Fact] public void ShouldNotExhibitBugBehavior() { // Arrange var input = /* condition that triggered bug */; // Act var result = _sut.MethodUnderTest(input); // Assert Assert.NotEqual(/* bug behavior */, result); Assert.Equal(/* correct behavior */, result); } } ``` ## Common Anti-Patterns to Avoid ### ❌ Testing the fix, not the bug ```typescript // BAD: Tests that the fix exists it('should call the new validation method', () => { expect(newValidationMethod).toHaveBeenCalled(); }); // GOOD: Tests that the bug behavior doesn't occur it('should reject invalid input', () => { expect(() => process(invalidInput)).toThrow('Validation error'); }); ``` ### ❌ Vague assertions ```typescript // BAD expect(result).toBeTruthy(); // GOOD expect(result.status).toBe('success'); expect(result.errors).toHaveLength(0); ``` ### ❌ Testing too much ```typescript // BAD: Unrelated assertions it('should fix the bug', () => { // Tests 10 different behaviors }); // GOOD: Focused on specific behavior it('should not allow null values', () => { // Tests only null handling }); ``` ## References - Bug context: Use `bug-context.md` for exact reproduction steps - Root cause: Use `verified-rca.md` for edge cases to cover - Existing tests: Check `research/codebase-research.md` for test patterns in this repo --- Source attribution: David-Li0406 Original project: https://github.com/David-Li0406/meta-skill-evloving/blob/ca3a335628981df10c36e00cb9850df2c247ab9a/skill-flow/data/skills-refined-36k/skillsmp/bug-fix-testing/SKILL.md License: Apache-2.0 License information: https://www.apache.org/licenses/LICENSE-2.0 Original upstream instructions; downloaded from Dave AI. ## Upstream license notice Apache License Version 2.0, January 2004 http://www.apache.org/licenses/ TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION 1. 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See the License for the specific language governing permissions and limitations under the License. # Dave AI resource metadata Creator / publisher: David-Li0406 Original project: https://github.com/David-Li0406/meta-skill-evloving/blob/ca3a335628981df10c36e00cb9850df2c247ab9a/skill-flow/data/skills-refined-36k/skillsmp/bug-fix-testing/SKILL.md Attribution basis: Source repository record Fields of work: Development & Engineering Roles: Backend Developer, Frontend Developer, QA / Test Engineer Specialties: Testing Tools: Jest, Pytest, Xunit Country applicability: Country not specified Classification basis: Source catalog labels Instruction SHA-256: 6f00f38f38c78a7137c9fc1f353d06b139636323e3fa373fa1ff5aee6c9e3e39