What common mistake do developers make with Email testing, why does the mistake cause problems, and what is the safer approach?

What common mistake do developers make with Email testing, why does the mistake cause problems, and what is the safer approach? One recurring problem with email testing is applying it without understanding the boundary it protects. Hard-coding SMTP passwords or API keys inside a Mailable class instead of using environment-backed configuration. In addition, Laravel testing helpers allow applications to assert that a specific mailable was sent without contacting a real mail provider. Safer engineering approach: keep the responsibility in the correct layer, use the framework's supported API, validate and authorize inputs, avoid hidden side effects, and verify the behavior with tests.