Closes Issue #108: Can't add tasks or open lists with custom region s…

…ettings.

- Changed NSDateFormatter locale in TTMDateUtility class to work around bugs related to setting the "high" date in some locales (namely Russia with 12 hour clock).
- Integration tests were performed with several locales. Unit tests all passed.

TodoTxtMac/TTMDateUtility.m

@@ -59,18 +59,26 @@ + (NSDate*)convertStringToDate:(NSString*)dateString {
     NSString *dateTimeString = [dateString stringByAppendingString:@" 00:00:00"];
 
     // Convert dateString to NSDate.
-    NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
+    NSDateFormatter *dateFormatter = [self dateFormatter];
     [dateFormatter setDateFormat:@"yyyy-MM-dd HH:mm:ss"];
     return [dateFormatter dateFromString:dateTimeString];
 }
 
++ (NSDateFormatter*)dateFormatter {
+    NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
+    NSCalendar *gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:NSCalendarIdentifierGregorian];
+    [dateFormatter setCalendar:gregorian];
+    [dateFormatter setLocale:[NSLocale systemLocale]];
+    [dateFormatter setDateFormat:@"yyyy-MM-dd"];
+    return dateFormatter;
+}
+
 + (NSString*)convertDateToString:(NSDate*)date {
     if (!date) {
         return nil;
     }
-    NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
-    [dateFormatter setDateFormat:@"yyyy-MM-dd"];
-        return [dateFormatter stringFromDate:date];
+    NSDateFormatter *dateFormatter = [self dateFormatter];
+    return [dateFormatter stringFromDate:date];
 }
 
 + (NSDate*)today {
@@ -175,8 +183,7 @@ + (NSDate*)relativeDateFromWeekdayName:(NSString*)weekdayName
         return nil;
     }
 
-    NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
-    [dateFormatter setLocale:[NSLocale currentLocale]];
+    NSDateFormatter *dateFormatter = [self dateFormatter];
     [dateFormatter setDateFormat:dateFormat];
 
     NSDate *todaysDate = [self today];

TodoTxtMacTests/TTMDateUtility_UnitTests.m

@@ -64,7 +64,7 @@ - (void)tearDown {
     [super tearDown];
 }
 
-- (void)testDateConversions {
+- (void)testDateConversions_WithNormalDate {
     NSDate *firstDate = [TTMDateUtility convertStringToDate:@"2014-01-01"];
     NSLog(@"firstDate: %@", firstDate);
     NSString *firstDateString = [TTMDateUtility convertDateToString:firstDate];
@@ -74,6 +74,26 @@ - (void)testDateConversions {
     XCTAssertEqualObjects(firstDate, secondDate);
 }
 
+- (void)testDateConversions_WithHighDate {
+    NSDate *firstDate = [TTMDateUtility convertStringToDate:@"9999-12-31"];
+    NSLog(@"firstDate: %@", firstDate);
+    NSString *firstDateString = [TTMDateUtility convertDateToString:firstDate];
+    NSLog(@"firstDateString: %@", firstDateString);
+    NSDate *secondDate = [TTMDateUtility convertStringToDate:firstDateString];
+    NSLog(@"secondDate: %@", secondDate);
+    XCTAssertEqualObjects(firstDate, secondDate);
+}
+
+- (void)testDateConversions_WithLowDate {
+    NSDate *firstDate = [TTMDateUtility convertStringToDate:@"1900-01-01"];
+    NSLog(@"firstDate: %@", firstDate);
+    NSString *firstDateString = [TTMDateUtility convertDateToString:firstDate];
+    NSLog(@"firstDateString: %@", firstDateString);
+    NSDate *secondDate = [TTMDateUtility convertStringToDate:firstDateString];
+    NSLog(@"secondDate: %@", secondDate);
+    XCTAssertEqualObjects(firstDate, secondDate);
+}
+
 - (void)testAddDaysToDate {
     NSDate *firstDate = [TTMDateUtility convertStringToDate:@"2014-01-01"];
     NSDate *secondDate = [TTMDateUtility convertStringToDate:@"2014-01-02"];