test(cliprdr): simplify drop-effect FormatDataRequest test (drop redundant initiate_file_copy call)

Author: Clint Christopher Canada

crates/ironrdp-testsuite-core/tests/clipboard/preferred_drop_effect.rs

@@ -79,29 +79,31 @@ fn initiate_file_copy_advertises_drop_effect_alongside_file_group_descriptor() {
 /// A `FormatDataRequest` for the drop-effect format id is answered
 /// inline by `Cliprdr` itself (not forwarded to the backend) with the
 /// 4-byte little-endian `DROPEFFECT_COPY = 0x00000001` payload.
+///
+/// Keys off the format *name* (`PREFERRED_DROP_EFFECT`) when looking up
+/// the id — wire-faithful (the remote keys off the name too), and
+/// resilient to any internal-id constant changes upstream.
+///
+/// If `local_drop_effect_format_id` ever stops being set by
+/// `initiate_file_copy` (or the inline short-circuit in
+/// `handle_format_data_request` is removed), this test fails because
+/// `TestBackend::on_format_data_request` is a no-op — the request
+/// would fall through to the backend, no response would be emitted,
+/// and `responses.len()` would be `0`.
 #[test]
 fn format_data_request_for_drop_effect_returns_dropeffect_copy_inline() {
     let mut cliprdr = init_ready_client();
 
-    // Drive `initiate_file_copy` so the server sets its
-    // `local_drop_effect_format_id` and starts recognizing requests for
-    // it. Discard the outbound FormatList — covered by the test above.
+    // Drive `initiate_file_copy`; the returned FormatList carries the
+    // drop-effect format we need to query.
     let files = vec![FileDescriptor::new("doc.txt").with_file_size(42)];
-    let _ = cliprdr.initiate_file_copy(files).unwrap();
-
-    // Find the drop-effect format id from the advertised FormatList by
-    // re-driving the call would be circular; instead, key off the format
-    // *name* by walking the FormatList we just emitted. Easier and
-    // wire-faithful since the remote keys off the name too.
-    let initiate_msgs: Vec<SvcMessage> = cliprdr
-        .initiate_file_copy(vec![FileDescriptor::new("d.txt").with_file_size(1)])
-        .unwrap()
-        .into();
+    let initiate_msgs: Vec<SvcMessage> = cliprdr.initiate_file_copy(files).unwrap().into();
+
     decode_pdu!(&initiate_msgs[0] => initiate_bytes, initiate_pdu);
     let ClipboardPdu::FormatList(format_list) = initiate_pdu else {
-        panic!("expected FormatList");
+        panic!("expected FormatList, got {initiate_pdu:?}");
     };
-    let drop_effect_format = format_list
+    let drop_effect_id = format_list
         .get_formats(true)
         .unwrap()
         .into_iter()
@@ -110,8 +112,8 @@ fn format_data_request_for_drop_effect_returns_dropeffect_copy_inline() {
                 .as_ref()
                 .is_some_and(|n| n == &ClipboardFormatName::PREFERRED_DROP_EFFECT)
         })
-        .expect("Preferred DropEffect must be advertised");
-    let drop_effect_id = drop_effect_format.id;
+        .expect("initiate_file_copy must advertise Preferred DropEffect")
+        .id;
 
     // Simulate the remote asking for the drop-effect format.
     let request_pdu = ClipboardPdu::FormatDataRequest(FormatDataRequest { format: drop_effect_id });
@@ -121,7 +123,7 @@ fn format_data_request_for_drop_effect_returns_dropeffect_copy_inline() {
     assert_eq!(
         responses.len(),
         1,
-        "drop-effect FormatDataRequest should be answered inline with one FormatDataResponse"
+        "drop-effect FormatDataRequest must be answered inline with one FormatDataResponse"
     );
 
     decode_pdu!(&responses[0] => resp_bytes, resp_pdu);
@@ -131,8 +133,8 @@ fn format_data_request_for_drop_effect_returns_dropeffect_copy_inline() {
     assert!(!response.is_error(), "response must not be an error");
 
     // [MS-RDPECLIP] Preferred DropEffect payload is a 4-byte u32 LE.
-    // `DROPEFFECT_COPY = 0x00000001` is what we advertise as the only
-    // value `initiate_file_copy` ever produces.
+    // `DROPEFFECT_COPY = 0x00000001` is what `initiate_file_copy`
+    // semantically always means.
     assert_eq!(
         response.data(),
         &[0x01, 0x00, 0x00, 0x00],