Addressed issue #115: "Match spec expectation for partials not found"

HISTORY.rst

@@ -5,6 +5,7 @@ History
 -----------
 
 * Added support for dot notation and version 1.1.2 of the spec (issue #99). [rbp]
+* Missing partials now render as empty string per latest version of spec (issue #115).
 * Bugfix: falsey values now coerced to strings using str().
 * Bugfix: lambda return values for sections no longer pushed onto context stack (issue #113).
 * Bugfix: lists of lambdas for sections were not rendered (issue #114).

spec @ 9b1bc7ad

-Subproject commit bf6288ed6bd0ce8ccea6f1dac070b3d779132c3b
+Subproject commit 9b1bc7ad19247e9671304af02078f2ce30132665

pystache/commands/render.py

@@ -35,6 +35,7 @@ import sys
 #
 #   ValueError: Attempted relative import in non-package
 #
+from pystache.common import TemplateNotFoundError
 from pystache.renderer import Renderer
 
 
@@ -78,7 +79,7 @@ def main(sys_argv=sys.argv):
 
     try:
         template = renderer.load_template(template)
-    except IOError:
+    except TemplateNotFoundError:
         pass
 
     try:

pystache/common.py

 # coding: utf-8
 
 """
-Exposes common functions.
+Exposes functionality needed throughout the project.
 
 """
 
@@ -24,3 +24,13 @@ def read(path):
         return f.read()
     finally:
         f.close()
+
+
+class PystacheError(Exception):
+    """Base class for Pystache exceptions."""
+    pass
+
+
+class TemplateNotFoundError(PystacheError):
+    """An exception raised when a template is not found."""
+    pass

pystache/locator.py

@@ -9,6 +9,7 @@ import os
 import re
 import sys
 
+from pystache.common import TemplateNotFoundError
 from pystache import defaults
 
 
@@ -117,9 +118,8 @@ class Locator(object):
         path = self._find_path(search_dirs, file_name)
 
         if path is None:
-            # TODO: we should probably raise an exception of our own type.
-            raise IOError('Template file %s not found in directories: %s' %
-                          (repr(file_name), repr(search_dirs)))
+            raise TemplateNotFoundError('File %s not found in dirs: %s' %
+                                        (repr(file_name), repr(search_dirs)))
 
         return path
 

pystache/parsed.py

@@ -32,6 +32,9 @@ class ParsedTemplate(object):
         """
         self._parse_tree = parse_tree
 
+    def __repr__(self):
+        return "[%s]" % (", ".join([repr(part) for part in self._parse_tree]))
+
     def render(self, context):
         """
         Returns: a string of type unicode.

pystache/parser.py

@@ -9,12 +9,13 @@ This module is only meant for internal use by the renderengine module.
 
 import re
 
+from pystache.common import TemplateNotFoundError
 from pystache.parsed import ParsedTemplate
 
 
-DEFAULT_DELIMITERS = ('{{', '}}')
-END_OF_LINE_CHARACTERS = ['\r', '\n']
-NON_BLANK_RE = re.compile(r'^(.)', re.M)
+DEFAULT_DELIMITERS = (u'{{', u'}}')
+END_OF_LINE_CHARACTERS = [u'\r', u'\n']
+NON_BLANK_RE = re.compile(ur'^(.)', re.M)
 
 
 def _compile_template_re(delimiters=None):
@@ -215,10 +216,14 @@ class Parser(object):
 
         elif tag_type == '>':
 
-            template = engine.load_partial(tag_key)
+            try:
+                # TODO: make engine.load() and test it separately.
+                template = engine.load_partial(tag_key)
+            except TemplateNotFoundError:
+                template = u''
 
             # Indent before rendering.
-            template = re.sub(NON_BLANK_RE, leading_whitespace + r'\1', template)
+            template = re.sub(NON_BLANK_RE, leading_whitespace + ur'\1', template)
 
             func = engine._make_get_partial(template)
 

pystache/renderengine.py

@@ -35,7 +35,8 @@ class RenderEngine(object):
 
           load_partial: the function to call when loading a partial.  The
             function should accept a string template name and return a
-            template string of type unicode (not a subclass).
+            template string of type unicode (not a subclass).  If the
+            template is not found, it should raise a TemplateNotFoundError.
 
           literal: the function used to convert unescaped variable tag
             values to unicode, e.g. the value corresponding to a tag

pystache/renderer.py

@@ -8,6 +8,7 @@ This module provides a Renderer class to render templates.
 import sys
 
 from pystache import defaults
+from pystache.common import TemplateNotFoundError
 from pystache.context import ContextStack
 from pystache.loader import Loader
 from pystache.renderengine import RenderEngine
@@ -239,9 +240,8 @@ class Renderer(object):
             template = partials.get(name)
 
             if template is None:
-                # TODO: make a TemplateNotFoundException type that provides
-                # the original partials as an attribute.
-                raise Exception("Partial not found with name: %s" % repr(name))
+                raise TemplateNotFoundError("Name %s not found in partials: %s" %
+                                            (repr(name), type(partials)))
 
             # RenderEngine requires that the return value be unicode.
             return self._to_unicode_hard(template)

pystache/tests/common.py

@@ -168,6 +168,20 @@ class AssertIsMixin:
         self.assertTrue(first is second, msg="%s is not %s" % (repr(first), repr(second)))
 
 
+class AssertExceptionMixin:
+
+    """A unittest.TestCase mixin adding assertException()."""
+
+    # unittest.assertRaisesRegexp() is not available until Python 2.7:
+    #   http://docs.python.org/library/unittest.html#unittest.TestCase.assertRaisesRegexp
+    def assertException(self, exception_type, msg, callable, *args, **kwds):
+        try:
+            callable(*args, **kwds)
+            raise Exception("Expected exception: %s: %s" % (exception_type, repr(msg)))
+        except exception_type, err:
+            self.assertEqual(str(err), msg)
+
+
 class SetupDefaults(object):
 
     """

pystache/tests/test_locator.py

@@ -11,14 +11,15 @@ import sys
 import unittest
 
 # TODO: remove this alias.
+from pystache.common import TemplateNotFoundError
 from pystache.loader import Loader as Reader
 from pystache.locator import Locator
 
-from pystache.tests.common import DATA_DIR, EXAMPLES_DIR
+from pystache.tests.common import DATA_DIR, EXAMPLES_DIR, AssertExceptionMixin
 from pystache.tests.data.views import SayHello
 
 
-class LocatorTests(unittest.TestCase):
+class LocatorTests(unittest.TestCase, AssertExceptionMixin):
 
     def _locator(self):
         return Locator(search_dirs=DATA_DIR)
@@ -110,7 +111,8 @@ class LocatorTests(unittest.TestCase):
     def test_find_name__non_existent_template_fails(self):
         locator = Locator()
 
-        self.assertRaises(IOError, locator.find_name, search_dirs=[], template_name='doesnt_exist')
+        self.assertException(TemplateNotFoundError, "File 'doesnt_exist.mustache' not found in dirs: []",
+                             locator.find_name, search_dirs=[], template_name='doesnt_exist')
 
     def test_find_object(self):
         locator = Locator()

pystache/tests/test_renderer.py

@@ -13,9 +13,10 @@ import unittest
 from examples.simple import Simple
 from pystache import Renderer
 from pystache import TemplateSpec
+from pystache.common import TemplateNotFoundError
 from pystache.loader import Loader
 
-from pystache.tests.common import get_data_path, AssertStringMixin
+from pystache.tests.common import get_data_path, AssertStringMixin, AssertExceptionMixin
 from pystache.tests.data.views import SayHello
 
 
@@ -405,7 +406,7 @@ class RendererTests(unittest.TestCase, AssertStringMixin):
 # we no longer need to exercise all rendering code paths through
 # the Renderer.  It suffices to test rendering paths through the
 # RenderEngine for the same amount of code coverage.
-class Renderer_MakeRenderEngineTests(unittest.TestCase):
+class Renderer_MakeRenderEngineTests(unittest.TestCase, AssertExceptionMixin):
 
     """
     Check the RenderEngine returned by Renderer._make_render_engine().
@@ -444,7 +445,20 @@ class Renderer_MakeRenderEngineTests(unittest.TestCase):
         self.assertEqual(actual, "abc")
         self.assertEqual(type(actual), unicode)
 
-    def test__load_partial__not_found(self):
+    def test__load_partial__not_found__default(self):
+        """
+        Check that load_partial provides a nice message when a template is not found.
+
+        """
+        renderer = Renderer()
+
+        engine = renderer._make_render_engine()
+        load_partial = engine.load_partial
+
+        self.assertException(TemplateNotFoundError, "File 'foo.mustache' not found in dirs: ['.']",
+                             load_partial, "foo")
+
+    def test__load_partial__not_found__dict(self):
         """
         Check that load_partial provides a nice message when a template is not found.
 
@@ -455,11 +469,10 @@ class Renderer_MakeRenderEngineTests(unittest.TestCase):
         engine = renderer._make_render_engine()
         load_partial = engine.load_partial
 
-        try:
-            load_partial("foo")
-            raise Exception("Shouldn't get here")
-        except Exception, err:
-            self.assertEqual(str(err), "Partial not found with name: 'foo'")
+        # Include dict directly since str(dict) is different in Python 2 and 3:
+        #   <type 'dict'> versus <class 'dict'>, respectively.
+        self.assertException(TemplateNotFoundError, "Name 'foo' not found in partials: %s" % dict,
+                             load_partial, "foo")
 
     ## Test the engine's literal attribute.
 

pystache/tests/test_specloader.py

@@ -16,6 +16,7 @@ from examples.lambdas import Lambdas
 from examples.inverted import Inverted, InvertedLists
 from pystache import Renderer
 from pystache import TemplateSpec
+from pystache.common import TemplateNotFoundError
 from pystache.locator import Locator
 from pystache.loader import Loader
 from pystache.specloader import SpecLoader
@@ -42,7 +43,7 @@ class ViewTestCase(unittest.TestCase, AssertStringMixin):
         view = Tagless()
         renderer = Renderer()
 
-        self.assertRaises(IOError, renderer.render, view)
+        self.assertRaises(TemplateNotFoundError, renderer.render, view)
 
         # TODO: change this test to remove the following brittle line.
         view.template_rel_directory = "examples"
@@ -60,7 +61,8 @@ class ViewTestCase(unittest.TestCase, AssertStringMixin):
         renderer1 = Renderer()
         renderer2 = Renderer(search_dirs=EXAMPLES_DIR)
 
-        self.assertRaises(IOError, renderer1.render, spec)
+        actual = renderer1.render(spec)
+        self.assertString(actual, u"Partial: ")
 
         actual = renderer2.render(spec)
         self.assertEqual(actual, "Partial: No tags...")