Fix parsing dates with trailing spaces (Resolves #11) (#39)

lib/domain/dart_rss.dart

@@ -9,16 +9,21 @@ extension SafeParseDateTime on DateTime {
     if (str == null) {
       return null;
     }
+
     const dateFormatPatterns = [
       'EEE, d MMM yyyy HH:mm:ss Z',
     ];
+
+    // DateTime.parse returns null if the input has
+    // trailing spaces. Remove the spaces to avoid that.
+    final trimmedDate = str.trim();
     try {
-      return DateTime.parse(str);
+      return DateTime.parse(trimmedDate);
     } catch (_) {
       for (final pattern in dateFormatPatterns) {
         try {
           final format = DateFormat(pattern);
-          return format.parse(str);
+          return format.parse(trimmedDate);
         } catch (_) {}
       }
     }

test/safe_parse_date_time_test.dart

@@ -2,27 +2,32 @@ import 'package:dart_rss/dart_rss.dart';
 import 'package:test/test.dart';
 
 void main() {
-  group('about SafeParseDateTime, ', () {
-    test('it can parse ISO-8601', () {
+  group('SafeParseDateTime, ', () {
+    test('parses ISO-8601', () {
       final date = SafeParseDateTime.safeParse('2018-04-06T13:02:47Z')!;
 
       expect(date.year, 2018);
       expect(date.month, 4);
       expect(date.day, 6);
     });
 
-    test('it can parse American-English-Format', () {
-      final date =
-          SafeParseDateTime.safeParse('Tue, 02 Jul 2019 16:47:24 +0000')!;
+    test('parses American-English-Format', () {
+      final date = SafeParseDateTime.safeParse('Tue, 02 Jul 2019 16:47:24 +0000')!;
 
       expect(date.year, 2019);
       expect(date.month, 7);
       expect(date.day, 2);
     });
 
-    test('incorrect date returns null', () {
+    test('returns null for incorrect dates', () {
       final date = SafeParseDateTime.safeParse('Tue 12');
       expect(date, null);
     });
+
+    test('parses dates with trailing whitespaces', () {
+      final date = SafeParseDateTime.safeParse('2024-01-08T00:19:00Z ')!;
+
+      expect(date, DateTime.utc(2024, 1, 8, 0, 19, 0));
+    });
   });
 }