Testing email flows in CI without sending real messages

Email is often the least tested part of a product because tests would normally send real messages. Common test suites mock the email client and only check that a send was called, which misses broken templates. A more useful approach asserts on the rendered subject, recipient, and required links in both HTML and text parts, catching cases like links pointing to localhost. Mocks cannot detect DNS, authentication, or provider rejection, so a single real send per release to an internal address with header checks such as DKIM is recommended. Snapshotting rendered bodies and diffing them in CI also surfaces variable substitution errors early, and Volanea offers a render endpoint to support this kind of testing.