test: implement per-test isolation for integration tests

[nycomp]

Summary

Implements Option A variant (per-test reset) for issue #335, providing true test isolation while maintaining acceptable performance.

Changes

• tests/fixtures/services.py: Added ServiceManager.reset_test_data() method

  • Resets storage (SQLite in-memory DB, memory collections) between tests
  • Re-initializes auth/yapper services after reset
  • Preserves Flask apps for performance

• tests/integration/api/test_assignments.py:

  • Moved reset from tearDownClass() to tearDown()
  • Re-create test tokens in setUp() (required because reset clears credentials)
  • Removed test_00_* prefix from test_list_assignments_empty

Test Results

• All 12 integration tests pass (up from 6 failures before)
• Full integration test suite passes (18 tests)
• No test_00_* prefixes remaining in codebase

Performance Impact

Minimal: ~0.04s increase for 12-test suite (0.25s → 0.29s)

• reset_test_storage() is cheap (closes/reopens SQLite connection, clears dict)
• Flask apps are preserved (only storage is reset)

Usage Pattern for Other Tests

def setUp(self):
    self.client = self.app.test_client()
    self.app_context = self.app.app_context().push()
    # Re-create token since tearDown() clears credentials
    self.token = create_test_token(self.user_id)
    self.auth_headers = get_bearer_auth_headers(self.token)

def tearDown(self):
    self.app_context.pop()
    if hasattr(self, 'service_manager'):
        self.service_manager.reset_test_data()

Trade-offs

Pro	Con
True test isolation - no test ordering issues	Tests using bearer tokens must re-create tokens in setUp()
Removes test_00_* naming hack	Slightly slower (but negligible impact)
Cleaner, more maintainable tests

Fixes #335

🤖 Generated with Claude Code

[nycomp]

Fix #335