Download of MidiTest 1.0 for Mac was on the developer's website when we last checked. We cannot confirm if there is a free download of this app available. The actual developer of this free Mac application is SoundLib. Please check the Mac app with an antivirus before launch as it is downloaded from the developer's website, and we cannot ensure that it is safe. MidiTest for Mac lies within Audio & Video Tools, more precisely Editors & Converters.
From the developer:
If your audio software does not react to your external MIDI controller, this utility will help you verify that your system receives the MIDI messages from your external MIDI controller. The clear button allows you to clear the history and reset the 16 MIDI channels.
You may want to check out more software for Mac, such as MFilter or Tipard DVD Audio Ripper for Mac, which might be similar to MidiTest.