Is this product doing a build step when I start to run a unit test?
It keeps catching syntax and other errors in my code.
(again, as I said in a previous question, a much nicer workflow than ftp'ing to a server and watching pages crash there)
PHP Tools are performing continuous static code analysis of all your code, so all the errors and warnings are always listed in Visual Studio' Error List Window (as seen in docs/code validation/configuration).
In case you'd like to run additional commands upon run (F5 key), you can define PreBuildEvent tasks as described at https://docs.microsoft.com/en-us/cpp/build/how-to-use-build-events-in-msbuild-projects?view=msvc-160