diff --git a/LinqToObjectiveCTest/LinqToObjectiveCTestTests/NSArrayLinqExtensionsTest.m b/LinqToObjectiveCTest/LinqToObjectiveCTestTests/NSArrayLinqExtensionsTest.m
index 8ff3497..e6d4ec4 100755
--- a/LinqToObjectiveCTest/LinqToObjectiveCTestTests/NSArrayLinqExtensionsTest.m
+++ b/LinqToObjectiveCTest/LinqToObjectiveCTestTests/NSArrayLinqExtensionsTest.m
@@ -380,8 +380,8 @@ - (void)testGroupByWithNil
     
     // test the group keys
     NSArray* keys = [groupedByFirstLetter allKeys];
-    STAssertEqualObjects([NSNull null], keys[0], nil);
-    STAssertEqualObjects(@"B", keys[1], nil);
+    STAssertEqualObjects([NSNull null], keys[1], nil);
+    STAssertEqualObjects(@"B", keys[0], nil);
     
     // test that the correct items are in each group
     NSArray* groupOne = groupedByFirstLetter[[NSNull null]];
@@ -438,8 +438,8 @@ - (void)testToDictionaryWithValueSelectorWithNil
     
     // test the group keys
     NSArray* keys = [dictionary allKeys];
-    STAssertEqualObjects([NSNull null], keys[0], nil);
-    STAssertEqualObjects(@"B", keys[1], nil);
+    STAssertEqualObjects([NSNull null], keys[1], nil);
+    STAssertEqualObjects(@"B", keys[0], nil);
     
     // test the values
     STAssertEqualObjects(dictionary[[NSNull null]], @"jim", nil);
diff --git a/README.md b/README.md
index 25f996a..a5ad233 100644
--- a/README.md
+++ b/README.md
@@ -153,6 +153,14 @@ NSArray* sortedInput = [input linq_sort]; // 21, 25, 34
 NSArray* sortedInput = [input linq_sortDescending]; // 34, 25, 21
 ```
     
+### <a name="sum"></a>linq_sum
+
+```objc
+- (NSNumber *)linq_sum;
+```
+
+Sums the elements in the array.
+
 ### <a name="ofType"></a>linq_ofType
 
 ```objc