feat: separate draft pull requests into their own tab

tests/unit/diff.rs

@@ -445,7 +445,12 @@ fn pull_request_categories_keep_query_and_select_loaded_rows_before_completion()
     let mut state = DiffState::pull_requests("origin".into());
     assert_eq!(
         state.categories(),
-        [Category::Open, Category::Closed, Category::All]
+        [
+            Category::Open,
+            Category::Closed,
+            Category::Drafts,
+            Category::All
+        ]
     );
     state.take_request();
     state.handle(Input::Char('\t'));
@@ -464,6 +469,7 @@ fn pull_request_categories_keep_query_and_select_loaded_rows_before_completion()
     assert!(state.pull_request_partial());
     assert_eq!(state.entries().next().unwrap().label, "#2 Fix Ünicode");
     state.handle(Input::Char('\t'));
+    state.handle(Input::Char('\t'));
     state.apply_result(
         1,
         Ok(pull_page(
@@ -498,6 +504,79 @@ fn pull_request_categories_keep_query_and_select_loaded_rows_before_completion()
     ));
 }
 
+#[test]
+fn pull_request_drafts_filter_independently_and_share_open_loading_and_retry() {
+    let mut state = DiffState::pull_requests("origin".into());
+    state.take_request();
+    let mut page = pull_page(
+        false,
+        &[
+            (1, "Ready", "2024-01-01T00:00:00Z"),
+            (2, "Draft Ünicode", "2024-01-02T00:00:00Z"),
+        ],
+        true,
+    );
+    if let Outcome::PullRequestPage {
+        result: Ok(page), ..
+    } = &mut page
+    {
+        page.entries[1].0.category = Category::Drafts;
+    }
+    state.apply_result(1, Ok(page));
+    state.apply_result(
+        1,
+        Ok(pull_page(
+            true,
+            &[(3, "Closed", "2024-01-03T00:00:00Z")],
+            false,
+        )),
+    );
+    let labels = |state: &DiffState| {
+        state
+            .entries()
+            .map(|entry| entry.label.clone())
+            .collect::<Vec<_>>()
+    };
+    assert_eq!(labels(&state), ["#1 Ready"]);
+    state.handle(Input::BackTab);
+    assert_eq!(
+        labels(&state),
+        ["#3 Closed", "#2 Draft Ünicode", "#1 Ready"]
+    );
+    state.handle(Input::BackTab);
+    assert_eq!(labels(&state), ["#2 Draft Ünicode"]);
+    assert!(state.pull_request_partial());
+    state.apply_result(
+        1,
+        Ok(Outcome::PullRequestPage {
+            closed: false,
+            result: Err("open stream unavailable".into()),
+        }),
+    );
+    assert!(
+        state
+            .pull_request_notice()
+            .unwrap()
+            .contains("open stream unavailable")
+    );
+    state.handle(Input::Ctrl('r'));
+    assert_eq!(state.pull_request_retries, [1, 0]);
+    state.apply_result(1, Ok(pull_page(false, &[], false)));
+    assert!(!state.pull_request_partial());
+    for ch in "Ünicode Alice".chars() {
+        state.handle(Input::Char(ch));
+    }
+    assert_eq!(labels(&state), ["#2 Draft Ünicode"]);
+    state.handle(Input::Enter);
+    assert!(matches!(
+        state.take_request(),
+        Some(Operation::ResolvePullRequest(Revision {
+            target: RevisionTarget::PullRequest { number: 2, .. },
+            ..
+        }))
+    ));
+}
+
 #[test]
 fn pull_request_all_streams_sort_deduplicate_and_preserve_selection_identity() {
     let mut state = DiffState::pull_requests("origin".into());