Scheme: test if scheme examples can be opened

MANIFEST.in

@@ -9,6 +9,7 @@ recursive-include Orange/canvas/application/workflows *.ows
 
 recursive-include Orange/widgets *.png *.svg *.js *.css *.html
 recursive-include Orange/widgets/tests *.tab
+recursive-include Orange/widgets/tests/workflows *.ows
 recursive-include Orange/widgets/utils/plot *.fs *.vs *.gs *.obj
 
 recursive-include distribute *.svg *.desktop

Orange/widgets/tests/test_workflows.py

@@ -0,0 +1,38 @@
+from itertools import chain
+from os import listdir
+from os.path import isfile, join, dirname
+
+from Orange.canvas.application import workflows
+from Orange.canvas.scheme import widgetsscheme
+from Orange.canvas.scheme.readwrite import scheme_load
+from Orange.widgets.tests.base import WidgetTest
+
+
+def discover_workflows(tests_dir):
+    ows_path = join(tests_dir, "workflows")
+    ows_files = [f for f in listdir(ows_path)
+                 if isfile(join(ows_path, f)) and f.endswith(".ows")]
+    for ows_file in ows_files:
+        yield join(ows_path, ows_file)
+
+TEST_WORKFLOWS = chain(
+    [t.abspath() for t in workflows.example_workflows()],
+    discover_workflows(dirname(__file__))
+)
+
+
+class TestWorkflows(WidgetTest):
+    def test_scheme_examples(self):
+        """
+        Test if Orange workflow examples can be opened. Examples in canvas
+        and also those placed "workflows" subfolder.
+        GH-2240
+        """
+        for ows_file in TEST_WORKFLOWS:
+            new_scheme = widgetsscheme.WidgetsScheme()
+            with open(ows_file, "rb") as f:
+                try:
+                    scheme_load(new_scheme, f)
+                except Exception as e:
+                    self.fail("Old workflow '{}' could not be loaded\n'{}'".
+                              format(ows_file, str(e)))