Enumerate deterministic split-tree plans

docs/window-animations-plan.md

@@ -248,6 +248,9 @@ Current pure planner status:
 - Planner tests now include a deterministic split-tree generator. It builds
   valid weighted tiling layouts, derives leaf hierarchy metadata, mutates them
   through supported transitions, and runs the real planner plus exact validator.
+- The generated tests also include a bounded corpus of supported split-tree
+  transitions across both axes and directions. Each case is planned twice and
+  compared exactly to catch nondeterministic planner output.
 
 Tests:
 
@@ -258,6 +261,7 @@ Tests:
 - interruption restarts only affected phase groups
 - reversing direction produces equivalent motion in reverse
 - accepted and rejected plans expose deterministic strategy explanations
+- bounded generated split-tree corpus produces identical plans on repeated runs
 - child waits for parent/container-space phases when moving upward into a
   toplevel peer position
 - mono-mode tab switches do not animate, while entering/exiting mono can animate

src/animation/multiphase.rs

@@ -1473,11 +1473,47 @@ mod tests {
     }
 
     fn assert_generated_case_plans(old: &TestTree, new: &TestTree, bounds: Rect) {
+        assert_generated_case_plans_deterministically(old, new, bounds);
+    }
+
+    fn assert_generated_case_plans_deterministically(
+        old: &TestTree,
+        new: &TestTree,
+        bounds: Rect,
+    ) -> MultiphasePlanned {
         let req = generated_request(old, new, bounds);
         assert!(!overlaps(req.windows.iter().map(|window| window.from)));
         assert!(!overlaps(req.windows.iter().map(|window| window.to)));
-        let plan = plan_no_overlap(&req).unwrap();
-        assert!(validate_plan_continuous(&req, &plan));
+        let first = plan_no_overlap_explained(&req).unwrap();
+        let second = plan_no_overlap_explained(&req).unwrap();
+        assert_eq!(first, second);
+        assert_eq!(first.plan.phases.len(), first.explanation.phases.len());
+        assert_eq!(
+            first.explanation.validation,
+            ValidationExplanation::passed()
+        );
+        for phase in &first.explanation.phases {
+            assert!(phase.nodes.windows(2).all(|pair| pair[0].0 < pair[1].0));
+        }
+        assert!(validate_plan_continuous(&req, &first.plan));
+        first
+    }
+
+    fn bounds_for_axis(axis: PhaseAxis) -> Rect {
+        match axis {
+            PhaseAxis::Horizontal => rect(0, 0, 400, 100),
+            PhaseAxis::Vertical => rect(0, 0, 100, 400),
+        }
+    }
+
+    fn push_generated_case_bidirectional(
+        cases: &mut Vec<(TestTree, TestTree, Rect)>,
+        old: TestTree,
+        new: TestTree,
+        bounds: Rect,
+    ) {
+        cases.push((old.clone(), new.clone(), bounds));
+        cases.push((new, old, bounds));
     }
 
     fn request(windows: Vec<MultiphaseWindow>) -> MultiphaseRequest {
@@ -1798,6 +1834,105 @@ mod tests {
         assert_generated_case_plans(&vertical_new, &vertical_old, rect(0, 0, 100, 400));
     }
 
+    #[test]
+    fn bounded_generated_supported_split_tree_corpus_is_deterministic() {
+        let mut cases = vec![];
+        for axis in [PhaseAxis::Horizontal, PhaseAxis::Vertical] {
+            let child_axis = axis.other();
+            let bounds = bounds_for_axis(axis);
+
+            push_generated_case_bidirectional(
+                &mut cases,
+                split(10, axis, &[1, 1], vec![leaf(1), leaf(2)]),
+                split(10, axis, &[1, 1], vec![leaf(2), leaf(1)]),
+                bounds,
+            );
+            push_generated_case_bidirectional(
+                &mut cases,
+                split(10, axis, &[1, 1, 1], vec![leaf(1), leaf(2), leaf(3)]),
+                split(10, axis, &[1, 2, 1], vec![leaf(1), leaf(2), leaf(3)]),
+                bounds,
+            );
+            push_generated_case_bidirectional(
+                &mut cases,
+                split(
+                    10,
+                    axis,
+                    &[1, 1],
+                    vec![
+                        leaf(1),
+                        split(11, child_axis, &[1, 1], vec![leaf(2), leaf(3)]),
+                    ],
+                ),
+                split(10, axis, &[1, 2, 1], vec![leaf(1), leaf(2), leaf(3)]),
+                bounds,
+            );
+            push_generated_case_bidirectional(
+                &mut cases,
+                split(
+                    10,
+                    axis,
+                    &[1, 1],
+                    vec![
+                        split(11, child_axis, &[1, 1], vec![leaf(1), leaf(2)]),
+                        leaf(3),
+                    ],
+                ),
+                split(10, axis, &[1, 2, 1], vec![leaf(1), leaf(2), leaf(3)]),
+                bounds,
+            );
+            push_generated_case_bidirectional(
+                &mut cases,
+                split(
+                    10,
+                    axis,
+                    &[1, 1],
+                    vec![
+                        leaf(1),
+                        split(11, child_axis, &[1, 1], vec![leaf(2), leaf(3)]),
+                    ],
+                ),
+                split(
+                    10,
+                    axis,
+                    &[1, 3],
+                    vec![
+                        leaf(1),
+                        split(11, child_axis, &[3, 1], vec![leaf(2), leaf(3)]),
+                    ],
+                ),
+                bounds,
+            );
+            push_generated_case_bidirectional(
+                &mut cases,
+                split(
+                    10,
+                    axis,
+                    &[1, 1],
+                    vec![
+                        split(11, child_axis, &[1, 1], vec![leaf(1), leaf(2)]),
+                        leaf(3),
+                    ],
+                ),
+                split(
+                    10,
+                    axis,
+                    &[3, 1],
+                    vec![
+                        split(11, child_axis, &[1, 3], vec![leaf(1), leaf(2)]),
+                        leaf(3),
+                    ],
+                ),
+                bounds,
+            );
+        }
+
+        assert_eq!(cases.len(), 24);
+        for (old, new, bounds) in cases {
+            assert_generated_case_plans_deterministically(&old, &new, bounds);
+        }
+    }
+
     #[test]
     fn stack_extraction_creates_space_before_moving_child() {
         let req = request(vec![