Allow NSManagedObject formatter to be changed

Classes/NSManagedObject+ActiveRecord.h

@@ -47,4 +47,8 @@
 
 + (NSString *)entityName;
 
+#pragma mark - Date Formatting
+
++ (void)setFormatter:(NSString *)newFormatter;
+
 @end

Classes/NSManagedObject+ActiveRecord.m

@@ -219,7 +219,7 @@ - (void)setSafeValue:(id)value forKey:(id)key {
             value = [NSNumber numberWithDouble:[value doubleValue]];
 
         else if (attributeType == NSDateAttributeType)
-            value = [self.defaultFormatter dateFromString:value];
+            value = [self.formatter dateFromString:value];
     }
 
     [self setValue:value forKey:key];
@@ -234,15 +234,25 @@ - (BOOL)isIntegerAttributeType:(NSAttributeType)attributeType {
 
 #pragma mark - Date Formatting
 
-- (NSDateFormatter *)defaultFormatter {
-    static NSDateFormatter *sharedFormatter;
-    static dispatch_once_t singletonToken;
+static NSDateFormatter *sharedFormatter;
+static dispatch_once_t singletonToken;
+
++(NSDateFormatter *)sharedFormatter{
     dispatch_once(&singletonToken, ^{
-        sharedFormatter = [[NSDateFormatter alloc] init];
-        [sharedFormatter setDateFormat:@"yyyy-MM-dd HH:mm:ss z"];
+        if(!sharedFormatter){
+            sharedFormatter = [[NSDateFormatter alloc] init];
+            [sharedFormatter setDateFormat:@"yyyy-MM-dd HH:mm:ss z"];
+        }
     });
-
     return sharedFormatter;
 }
 
+- (NSDateFormatter *)formatter {
+    return [NSManagedObject sharedFormatter];
+}
+
++ (void)setFormatter:(NSString *)newFormatter {
+    [sharedFormatter setDateFormat:newFormatter];
+}
+
 @end

Example/SampleProjectTests/FindersAndCreatorsTests.m

@@ -176,6 +176,18 @@ void createSomePeople(NSArray *names, NSArray *surnames, NSManagedObjectContext
             Person *person = [Person create:@{ @"anniversary": [formatta stringFromDate:date] }];
             [[@([date timeIntervalSinceDate:person.anniversary]) should] beLessThan:@1];
         });
+
+        it(@"converts string from specified date format", ^{
+            [NSManagedObject setFormatter:@"HH:mm:ss"];
+            Person *person = [Person create:@{ @"anniversary": @"12:24:05" }];
+            [person.anniversary shouldNotBeNil];
+        });
+
+        it(@"can't convert string from specified date format", ^{
+            [NSManagedObject setFormatter:@"yyyy HH:mm:ss"];
+            Person *person = [Person create:@{ @"anniversary": @"12:24:05" }];
+            [person.anniversary shouldBeNil];
+        });
 
         it(@"doesn't update with nulls", ^{
             Person *person = fetchUniquePerson();