[aur-general] Customize testing in PKGBUILD

Hi, I'm maintaining the eccodes aur package and would like to enable some extra tests in PKGBUILD. This can be done by downloading extra testdata and put that into the main build dir. As good as this may seem, it significantly blows up the build time of the package. So I thought about somehow let the user decide whether to run those expensive extra tests at build. Unfortunately I could not find a recommended way of doing so. Would it be an option to check an environment variable, call it ENABLE_EXTRA_TESTS or so, and run those stuff only if set? And otherwise just run the usual tests without the extra data? Any thoughts? Thanks! -- MfG Jan