[geary/mjog/950-test-case-conversion-locale] RFC822MesageTest: Fix locale-sensitive test case

[Michael Gratton <mjog src gnome org>]

commit a64412e69690b3016e0ddcbc20dac49c833fccd4
Author: Michael Gratton <mike vee net>
Date:   Sat Aug 29 18:33:15 2020 +1000

    RFC822MesageTest: Fix locale-sensitive test case
    
    Use `ascii_down()` instead of `down()` so the test case is more robust
    in the face of being run under different locales.
    
    Fixes #950

 test/engine/rfc822/rfc822-message-test.vala | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/test/engine/rfc822/rfc822-message-test.vala b/test/engine/rfc822/rfc822-message-test.vala
index 083ea3d43..b7697dda3 100644
--- a/test/engine/rfc822/rfc822-message-test.vala
+++ b/test/engine/rfc822/rfc822-message-test.vala
@@ -306,7 +306,7 @@ This is the second line.
 
         string message_data = message.get_rfc822_buffer(SMTP_FORMAT).to_string();
         assert_true("To: Test <test example com>\r\n" in message_data);
-        assert_false("bcc" in message_data.down());
+        assert_false("bcc" in message_data.ascii_down());
     }
 
     public void get_rfc822_buffer_long_ascii_line() throws GLib.Error {