Add details to Missing Property error

[sound-fx]

Please consider the patch below. In reporting a missing property during validation, this include the name of the property in the ValidationError's reason.

(Sorry for the inline code. I haven't figured out how to properly submit a patch. The github's issues editor won't let me attach a *.patch file to this post, and other options I tried get rejected because I don't have permission to contribute.)

From 42c4a75835ccb98907c75b7611f550774e3e245f Mon Sep 17 00:00:00 2001
From: Greg Bullock <greg@nwra.com>
Date: Wed, 20 Apr 2016 15:30:37 -0700
Subject: [PATCH] Add details to Missing Property error

In reporting a missing property during validation, include the name of
the property in the ValidationError's reason.

---
 src/jsonspec/validators/draft04.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/jsonspec/validators/draft04.py b/src/jsonspec/validators/draft04.py
index adb6ee9..f6d67bb 100644
--- a/src/jsonspec/validators/draft04.py
+++ b/src/jsonspec/validators/draft04.py
@@ -380,7 +380,7 @@ class Draft04Validator(Validator):
             if key in obj:
                 if isinstance(dependencies, sequence_types):
                     for dep in set(dependencies) - set(obj.keys()):
-                        self.fail('Missing property', obj, pointer)
+                        self.fail('Missing property "{}"'.format(dep), obj, pointer)
                 else:
                     dependencies(obj)
         return obj
@@ -609,7 +609,7 @@ class Draft04Validator(Validator):
         if 'required' in self.attrs:
             for name in self.attrs['required']:
                 if name not in obj:
-                    self.fail('Missing property', obj, pointer)
+                    self.fail('Missing property "{}"'.format(name), obj, pointer)
         return obj

     def validate_type(self, obj, pointer=None):
-- 
2.7.1.windows.2