Merge branch 'bugfix/return-1-on-failure' into 'master'

[bugfix][test] return 1 on failure

See merge request !81

dune/geometry/test/test-fromvertexcount.cc

@@ -90,4 +90,5 @@ try {
 catch (Dune::Exception & e)
 {
   std::cout << "Error: " << e.what() << std::endl;
+  return 1;
 }