CPScanner: When the scanner did not accumulate any string, do not change (to nil) the object passed as a ref in ...intoSring:ref() methods. With tests.

Foundation/CPScanner.j

@@ -140,11 +140,14 @@
 - (BOOL)_performScanWithSelector:(SEL)s withObject:(id)arg into:(id)ref
 {
     var ret = [self performSelector:s withObject:arg];
-
+    
+    if (ret == nil)
+        return NO;
+        
     if (ref != nil)
         ref(ret);
 
-    return ret != NULL;
+    return YES;
 }
 
 /* ================================ */

Tests/Foundation/CPScannerTest.j

@@ -0,0 +1,25 @@
+@import <Foundation/Foundation.j>
+
+@implementation CPScannerTest : OJTestCase
+{
+}
+
+- (void)testNothingScanned
+{
+    var x = @"x",
+        str = x,
+        scanner,
+        result;
+    
+    scanner = [CPScanner scannerWithString:@"a"];
+    result = [scanner scanString:@"b" intoString:str];
+    [self assertFalse:result message:"Result should be FALSE"];
+    [self assertTrue:str === x message:"The string passed by reference should not change, is " + str];
+    
+    scanner = [CPScanner scannerWithString:@"a"];
+    result = [scanner scanUpToString:@"a" intoString:str];
+    [self assertFalse:result message:"Result should be FALSE"];
+    [self assertTrue:str === x message:"The string passed by reference should not change, is " + str];
+}
+
+@end