Redmine Project Types Relations

There are several failing tests in ProjectPatchTest class:

 FAIL ProjectTypesRelations::ProjectPatchTest#test_should_find_guests_before_updating_the_project_type_of_a_project (3.53s)
        Expected true to be nil or false
        plugins/redmine_project_types_relations/test/unit/project_patch_test.rb:70:in `block in <class:ProjectPatchTest>'

 FAIL ProjectTypesRelations::ProjectPatchTest#test_should_find_hosts_and_guests_before_updating_the_project_type_of_a_project (3.76s)
        --- expected
        +++ actual
        @@ -1 +1 @@
        -["cannot be changed, because there is 1 linked service project.", "cannot be changed, because there is 1 linked client project."]
        +["cannot be changed, because there is 1 linked service project."]
        plugins/redmine_project_types_relations/test/unit/project_patch_test.rb:89:in `block in <class:ProjectPatchTest>'

 FAIL ProjectTypesRelations::ProjectPatchTest#test_should_save_guest_and_host_relations_of_a_project (3.91s)
        Expected: [1]
          Actual: []
        plugins/redmine_project_types_relations/test/unit/project_patch_test.rb:44:in `block in <class:ProjectPatchTest>'