Added missing_tags attribute validation.

2 files changed, 21 insertions, 1 deletions

diff --git a/pystache/renderer.py b/pystache/renderer.py
index 7fc6fa8..bed5ed1 100644
--- a/pystache/renderer.py
+++ b/pystache/renderer.py
@@ -263,7 +263,14 @@ class Renderer(object):
         Return whether missing_tags is set to strict.
 
         """
-        return self.missing_tags == MissingTags.strict
+        val = self.missing_tags
+
+        if val == MissingTags.strict:
+            return True
+        elif val == MissingTags.ignore:
+            return False
+
+        raise Exception("Unsupported 'missing_tags' value: %s" % repr(val))
 
     def _make_resolve_partial(self):
         """
diff --git a/pystache/tests/test_renderer.py b/pystache/tests/test_renderer.py
index 8bc8941..69cc64d 100644
--- a/pystache/tests/test_renderer.py
+++ b/pystache/tests/test_renderer.py
@@ -639,6 +639,19 @@ class Renderer_MakeRenderEngineTests(unittest.TestCase, AssertStringMixin, Asser
         self.assertTrue(isinstance(s, unicode))
         self.assertEqual(type(escape(s)), unicode)
 
+    ## Test the missing_tags attribute.
+
+    def test__missing_tags__unknown_value(self):
+        """
+        Check missing_tags attribute: setting an unknown value.
+
+        """
+        renderer = Renderer()
+        renderer.missing_tags = 'foo'
+
+        self.assertException(Exception, "Unsupported 'missing_tags' value: 'foo'",
+                             renderer._make_render_engine)
+
     ## Test the engine's resolve_context attribute.
 
     def test__resolve_context(self):