git diff master > text.txt; ./bin/mail receive-test --to <configured-diff-create-address> < text.txt; a diff was successfully created...! email generated had a working link to the diff.
./bin/mail receive-test --to <configured-diff-create-address> < README.md; a diff was not created as expected...! email generated had a sensical error message, telling me that the mail body should have been generated via a diff command