Added a test that chars in passwords.rs must be ascii

It was already implied but it might be useful if they will be changed

cryptography/src/passwords.rs

@@ -95,3 +95,13 @@ pub fn check_master_pass(password: &str) -> PasswordValidity {
 
     flags
 }
+
+#[cfg(test)]
+mod tests {
+    use crate::passwords::CHARS;
+
+    #[test]
+    fn chars_must_be_ascii() {
+        assert!(CHARS.is_ascii())
+    }
+}