zim: remove postFixup, include checkPhase, disable tests

- wrap-python.nix used to set sys.argv[0] to the name of the script, but
it now sets the path so we won't have to do it here anymore
- tests were not found, so the correct file is now invoked

pkgs/applications/office/zim/default.nix

@@ -30,12 +30,13 @@ pythonPackages.buildPythonApplication rec {
     export makeWrapperArgs="--prefix XDG_DATA_DIRS : $out/share --argv0 $out/bin/.zim-wrapped"
   '';
 
-  postFixup = ''
-    substituteInPlace $out/bin/.zim-wrapped \
-    --replace "sys.argv[0] = 'zim'" "sys.argv[0] = '$out/bin/zim'"
+  # RuntimeError: could not create GtkClipboard object
+  doCheck = false;
+
+  checkPhase = ''
+    python test.py
   '';
 
-  doCheck = true;
 
   meta = {
       description = "A desktop wiki";