python3Packages.gst-python: fix installCheckPhase

Tests weren't calling `preCheck` as expected which is probably why the
tests failed in Darwin on Hydra.

pkgs/development/python-modules/gst-python/default.nix

@@ -89,14 +89,14 @@ buildPythonPackage rec {
     (lib.mesonEnable "tests" gst-python.doInstallCheck)
   ];
 
-  # Tests are very flaky on Darwin.
-  # See: https://github.com/NixOS/nixpkgs/issues/454955
-  doCheck = !stdenv.hostPlatform.isDarwin;
-
   # `buildPythonPackage` uses `installCheckPhase` and leaves `checkPhase`
   # empty. It renames `doCheck` from its arguments, but not `checkPhase`.
   # See: https://github.com/NixOS/nixpkgs/issues/47390
-  installCheckPhase = "mesonCheckPhase";
+  installCheckPhase = ''
+    runHook preCheck
+    mesonCheckPhase
+    runHook postCheck
+  '';
 
   preCheck = lib.optionalString stdenv.hostPlatform.isDarwin ''
     export DYLD_LIBRARY_PATH="${gst_all_1.gst-plugins-base}/lib"