Add test for ticket:4368

Belonging to [master]:
  - OpenModelica/OMCompiler#2099
  - OpenModelica/OpenModelica-testsuite#815

openmodelica/diff/Makefile

@@ -20,6 +20,7 @@ ticket3619.mos \
 ticket3642.mos \
 Ticket4110.mos \
 ticket4153.mos \
+ticket4368.mos \
 UTF8.mos
 
 # test that currently fail. Move up when fixed.

openmodelica/diff/ticket4368.mos

@@ -0,0 +1,26 @@
+// status: correct
+// Based on https://trac.openmodelica.org/OpenModelica/ticket/4368
+
+diffModelicaFileListings("model test
+  M x;
+// comment
+
+equation
+  connect(a, b);
+end test;","model test
+  M y;
+  // comment
+equation
+  connect(a, c);
+end test;", OpenModelica.Scripting.DiffFormat.color);getErrorString();
+
+// Result:
+// "model test
+//   M y;
+// // comment
+//
+// equation
+//   connect(a, c);
+// end test;"
+// ""
+// endResult