diff --git a/cryptography/src/passwords.rs b/cryptography/src/passwords.rs
index 0653bce..ada5ce7 100644
--- a/cryptography/src/passwords.rs
+++ b/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())
+    }
+}