CPArray (CPPredicate): -filteredArrayUsingPredicate: and -filterUsingPredicate:

Use CPArray methods (not js array) because the receiver can be a CPArray subclass. With tests.

Fixes the bug reported here: https://groups.google.com/forum/?pli=1#!topic/objectivej/8q9hqbZZUv0

Foundation/CPPredicate/CPPredicate.j

@@ -210,7 +210,7 @@
 
     for (; i < count; i++)
     {
-        var object = self[i];
+        var object = [self objectAtIndex:i];
         if ([predicate evaluateWithObject:object])
             result.push(object);
     }
@@ -224,7 +224,7 @@
 
     while (count--)
     {
-        if (![predicate evaluateWithObject:self[count]])
+        if (![predicate evaluateWithObject:[self objectAtIndex:count]])
             splice(count, 1);
     }
 }

Tests/AppKit/CPArrayControllerTest.j

@@ -547,6 +547,18 @@
     [self assertTrue:[[arrayController arrangedObjects] count] > 0];
 }
 
+- (void)testArrangedObjectsWithPredicateFilteringAfterContentArrayBinding
+{
+    _contentArray = [self makeTestArray];
+
+    var arrayController = [[CPArrayController alloc] init];
+    [arrayController bind:@"contentArray" toObject:self withKeyPath:@"_contentArray" options:nil];
+    [arrayController setFilterPredicate:[CPPredicate predicateWithFormat:@"department.name BEGINSWITH 'Capp'"]];
+    
+    var arrangedCount = [[arrayController arrangedObjects] count];
+    [self assertTrue:(arrangedCount == 2) message:@"Count should be 2 and is " + arrangedCount];
+}
+
 /**
     In a table with arranged contents like [1, 1, 2, 1], selecting the second '1' and removing it
     should result in [1, 2, 1] - not [2]. E.g. we don't use removeObject:1 but only remove the

Tests/Foundation/CPPredicateTest.j

@@ -3,6 +3,7 @@
 @implementation CPPredicateTest : OJTestCase
 {
     CPDictionary dict;
+    CPArray simpleArray;
 }
 
 - (id)init
@@ -26,6 +27,8 @@
 
         d = [CPDictionary dictionaryWithObjects:objects forKeys:keys];
         [dict setObject:d forKey:@"Record2"];
+        
+        simpleArray = [CPArray arrayWithObjects:@"a", @"b", @"ac", @"bc"];
 
     }
     return self;
@@ -436,6 +439,16 @@
     [self assert:pred1 equals:pred2];
 }
 
+- (void)testProxyArrayFiltering
+{
+    var proxyArray = [self mutableArrayValueForKey:@"simpleArray"],
+        predicate = [CPPredicate predicateWithFormat:@"SELF CONTAINS 'a'"];
+    
+    var filtered = [proxyArray filteredArrayUsingPredicate:predicate];
+    
+    [self assertTrue:([filtered count] == 2) message:@"Count should be 2 and is " + [filtered count]];
+}
+
 @end
 
 @implementation CPObject (PredicateTesting)