From 5d88d07edc02c3f6d943c0603c0f818e8fe64387 Mon Sep 17 00:00:00 2001
From: Antoine Mercadal <antoine.mercadal@gmail.com>
Date: Tue, 5 Jan 2016 12:54:21 -0800
Subject: [PATCH] FIXED: CPPredicate's predicateFormat with a CPNull value as
 right expression wasn't working

Previously a CPPredicate created with format `value == nil` was converted back to `value == <CPNull @ xxxx>`

This patch ensures `predicateFormat` returns `value == nil`

Test added in CPPredicateTest.j
---
 Foundation/CPPredicate/_CPConstantValueExpression.j |  3 +++
 Tests/Foundation/CPPredicateTest.j                  | 11 +++++++++++
 2 files changed, 14 insertions(+)

diff --git a/Foundation/CPPredicate/_CPConstantValueExpression.j b/Foundation/CPPredicate/_CPConstantValueExpression.j
index 617c9b10a..397ce6371 100644
--- a/Foundation/CPPredicate/_CPConstantValueExpression.j
+++ b/Foundation/CPPredicate/_CPConstantValueExpression.j
@@ -66,6 +66,9 @@
     if ([_value isKindOfClass:[CPString class]])
         return @"\"" + _value + @"\"";
 
+    if (_value === [CPNull null])
+        return @"nil";
+
     return [_value description];
 }
 
diff --git a/Tests/Foundation/CPPredicateTest.j b/Tests/Foundation/CPPredicateTest.j
index f167d5513..ff89760c0 100644
--- a/Tests/Foundation/CPPredicateTest.j
+++ b/Tests/Foundation/CPPredicateTest.j
@@ -577,6 +577,17 @@
     }
 }
 
+- (void)testPredicateFormatWithNullGeneratesCorrectString
+{
+    var predicate1 = [CPPredicate predicateWithFormat:@"value == %@", [CPNull null]],
+        predicate2 = [CPPredicate predicateWithFormat:@"value == null"],
+        predicate3 = [CPPredicate predicateWithFormat:@"value == nil"];
+
+    [self assert:[predicate1 predicateFormat] equals:@"value == nil"];
+    [self assert:[predicate2 predicateFormat] equals:@"value == nil"];
+    [self assert:[predicate3 predicateFormat] equals:@"value == nil"];
+}
+
 @end
 
 @implementation CPObject (PredicateTesting)