add test for binary word-encoded filenames

src/mimeparser.rs

@@ -1489,6 +1489,15 @@ mod tests {
         assert_eq!(filename, Some("Maßnahmen Okt. 2020.html".to_string()))
     }
 
+    #[test]
+    fn test_get_attachment_filename_encoded_words_binary() {
+        let mail = load_mail_with_attachment(include_bytes!(
+            "../test-data/message/attach_filename_encoded_words_binary.eml"
+        ));
+        let filename = get_attachment_filename(&mail.subparts[1]).unwrap();
+        assert_eq!(filename, Some(" § 165 Abs".to_string()))
+    }
+
     #[test]
     fn test_get_attachment_filename_encoded_words_cont() {
         // test continued encoded-words and also test apostropes work that way

test-data/message/attach_filename_encoded_words_binary.eml

@@ -0,0 +1,26 @@
+Subject: Test binary-encoded-words filenames
+Message-ID: 123456@testrun.org
+Date: Sat, 07 Dec 2019 19:00:27 +0000
+Chat-Version: 1.0
+To: recp@testrun.org
+From: sender@testrun.org
+Content-Type: multipart/mixed; boundary="==BREAK=="
+
+
+--==BREAK==
+Content-Type: text/plain; charset=utf-8
+
+test binary word-encoded filename,
+filename is " § 165 Abs" - note the leading space.
+
+as a side-effect, this also tests that the encoding-name
+also works in UPPERCASE.
+
+--==BREAK==
+Content-Type: text/html
+Content-Disposition: attachment; filename="=?UTF-8?B?IMKnIDE2NSBBYnM=?=";
+Content-Transfer-Encoding: base64
+
+PGh0bWw+PGJvZHk+dGV4dDwvYm9keT5kYXRh
+
+--==BREAK==--