Emails that end with dash should return correct failure reason

Author: RohanNagar

src/main/java/com/sanctionco/jmail/JMail.java

@@ -170,11 +170,16 @@ private static EmailValidationResult validateInternal(String email) {
     // email cannot start with '.'
     if (email.charAt(0) == '.') return EmailValidationResult.failure(FailureReason.STARTS_WITH_DOT);
 
-    // email cannot end with '.' or '-'
-    if (email.charAt(size - 1) == '.' || email.charAt(size - 1) == '-') {
+    // email cannot end with '.'
+    if (email.charAt(size - 1) == '.') {
       return EmailValidationResult.failure(FailureReason.ENDS_WITH_DOT);
     }
 
+    // email cannot end with '-'
+    if (email.charAt(size - 1) == '-') {
+      return EmailValidationResult.failure(FailureReason.DOMAIN_PART_ENDS_WITH_DASH);
+    }
+
     boolean atFound = false;               // set to true when the '@' character is found
     boolean inQuotes = false;              // set to true if we are currently within quotes
     boolean previousDot = false;           // set to true if the previous character is '.'

src/test/java/com/sanctionco/jmail/FailureReasonTest.java

@@ -17,6 +17,7 @@ public static Stream<Arguments> provideTestEmails() {
         Arguments.of("te[st@test.com", FailureReason.DISALLOWED_UNQUOTED_CHARACTER),
         Arguments.of("test@", FailureReason.DOMAIN_MISSING),
         Arguments.of("test@test-.com", FailureReason.DOMAIN_PART_ENDS_WITH_DASH),
+        Arguments.of("email@example.com-", FailureReason.DOMAIN_PART_ENDS_WITH_DASH),
         Arguments.of("test@my.-test.com", FailureReason.DOMAIN_PART_STARTS_WITH_DASH),
         Arguments.of(
             "first.last@x234567890123456789012345678901234567890123456789012345678901234.test.org",