Fixes issue #61: "Renderer class should handle load_template not returning unicode"

pystache/renderengine.py

@@ -55,10 +55,14 @@ class RenderEngine(object):
 
     modifiers = Modifiers()
 
-    def __init__(self, load_template=None, literal=None, escape=None):
+    def __init__(self, load_partial=None, literal=None, escape=None):
         """
         Arguments:
 
+          load_partial: a function for loading templates by name when
+            loading partials.  The function should accept a template name
+            and return a unicode template string.
+
           escape: a function that takes a unicode or str string,
             converts it to unicode, and escapes and returns it.
 
@@ -68,7 +72,7 @@ class RenderEngine(object):
         """
         self.escape = escape
         self.literal = literal
-        self.load_template = load_template
+        self.load_partial = load_partial
 
     def render(self, template, context):
         """
@@ -178,7 +182,7 @@ class RenderEngine(object):
 
     @modifiers.set('>')
     def _render_partial(self, template_name):
-        markup = self.load_template(template_name)
+        markup = self.load_partial(template_name)
         return self._render(markup)
 
     @modifiers.set('=')
@@ -194,7 +198,7 @@ class RenderEngine(object):
 
     @modifiers.set('{')
     @modifiers.set('&')
-    def render_unescaped(self, tag_name):
+    def _render_unescaped(self, tag_name):
         """
         Render a tag without escaping it.
 

pystache/renderer.py

@@ -138,7 +138,12 @@ class Renderer(object):
         Return a RenderEngine instance for rendering.
 
         """
-        engine = RenderEngine(load_template=self.load_template,
+        # Make sure the return value of load_template is unicode.
+        def load_partial(name):
+            template = self.load_template(name)
+            return self.unicode(template)
+
+        engine = RenderEngine(load_partial=load_partial,
                               literal=self.literal,
                               escape=self._unicode_and_escape)
         return engine

tests/test_renderengine.py

@@ -21,13 +21,12 @@ class RenderEngineTestCase(unittest.TestCase):
         Create and return a default RenderEngine for testing.
 
         """
-        load_template = None
         to_unicode = unicode
 
         escape = lambda s: cgi.escape(to_unicode(s))
         literal = to_unicode
 
-        engine = RenderEngine(literal=literal, escape=escape, load_template=None)
+        engine = RenderEngine(literal=literal, escape=escape, load_partial=None)
         return engine
 
     def _assert_render(self, expected, template, *context, **kwargs):
@@ -35,7 +34,7 @@ class RenderEngineTestCase(unittest.TestCase):
         engine = kwargs.get('engine', self._engine())
 
         if partials is not None:
-            engine.load_template = lambda key: partials[key]
+            engine.load_partial = lambda key: partials[key]
 
         context = Context(*context)
 
@@ -49,23 +48,23 @@ class RenderEngineTestCase(unittest.TestCase):
 
         """
         # In real-life, these arguments would be functions
-        engine = RenderEngine(load_template="load_template", literal="literal", escape="escape")
+        engine = RenderEngine(load_partial="foo", literal="literal", escape="escape")
 
+        self.assertEquals(engine.load_partial, "foo")
         self.assertEquals(engine.escape, "escape")
         self.assertEquals(engine.literal, "literal")
-        self.assertEquals(engine.load_template, "load_template")
 
     def test_render(self):
         self._assert_render('Hi Mom', 'Hi {{person}}', {'person': 'Mom'})
 
-    def test_render__load_template(self):
+    def test_render__load_partial(self):
         """
         Test that render() uses the load_template attribute.
 
         """
         engine = self._engine()
         partials = {'partial': "{{person}}"}
-        engine.load_template = lambda key: partials[key]
+        engine.load_partial = lambda key: partials[key]
         self._assert_render('Hi Mom', 'Hi {{>partial}}', {'person': 'Mom'}, engine=engine)
 
     def test_render__literal(self):

tests/test_renderer.py

@@ -244,16 +244,19 @@ class RendererTestCase(unittest.TestCase):
     # correctly, we no longer need to test the rendering code paths through
     # the Renderer.  We can test rendering paths through only the RenderEngine
     # for the same amount of code coverage.
-    def test_make_render_engine__load_template(self):
+    def test_make_render_engine__load_partial(self):
         """
-        Test that _make_render_engine() passes the right load_template.
+        Test that _make_render_engine() constructs and passes load_partial correctly.
 
         """
         renderer = Renderer()
-        renderer.load_template = "foo"  # in real life, this would be a function.
+        renderer.unicode = lambda s: s.upper()  # a test version.
+        # In real-life, the partial would be different with each name.
+        renderer.load_template = lambda name: "partial"
 
         engine = renderer._make_render_engine()
-        self.assertEquals(engine.load_template, "foo")
+        # Make sure it calls unicode.
+        self.assertEquals(engine.load_partial('name'), "PARTIAL")
 
     def test_make_render_engine__literal(self):
         """