Add String value to the Error::UnexpectedError variant

To make debugging of unexpected errors easier, this patch adds an
associated String value with a description of the unexpected behavior to
the UnexpectedError variant of the Error enum.

1 files changed, 1 insertions, 1 deletions

diff --git a/tests/pws.rs b/tests/pws.rs
index 7169695..47e9703 100644
--- a/tests/pws.rs
+++ b/tests/pws.rs
@@ -16,7 +16,7 @@ use nitrokey_test::test as test_device;
 fn get_slot_name_direct(slot: u8) -> Result<String, Error> {
     let ptr = unsafe { nitrokey_sys::NK_get_password_safe_slot_name(slot) };
     if ptr.is_null() {
-        return Err(Error::UnexpectedError);
+        return Err(Error::UnexpectedError("null pointer".to_owned()));
     }
     let s = unsafe { CStr::from_ptr(ptr).to_string_lossy().into_owned() };
     unsafe { free(ptr as *mut c_void) };