200- [ ] Tests fail when your new logic is broken
201- [ ] Happy path is covered
202▶- [ ] Edge cases and error conditions are tested
203- [ ] Use fixtures/mocks for external dependencies
204- [ ] Tests are deterministic (no flaky tests)
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208
209- No `eval()`, `exec()`, or `pickle` on user-controlled input
210▶- Proper exception handling (no bare `except:`) and use a `msg` variable for error messages
211- Remove unreachable/commented code before committing
212- Race conditions or resource leaks (file handles, sockets, threads).
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232
233 Raises:
234▶ InvalidEmailError: If the email address format is invalid.
235 SMTPConnectionError: If unable to connect to email server.
236 """
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235▶ SMTPConnectionError: If unable to connect to email server.
236 """
237```