diff --git a/tests/unit/player-edge-assist.test.ts b/tests/unit/player-edge-assist.test.ts
new file mode 100644
index 00000000..a1c4e083
--- /dev/null
+++ b/tests/unit/player-edge-assist.test.ts
@@ -0,0 +1,115 @@
+import { describe, expect, it } from "vitest";
+
+import { FIRST_PERSON_PLAYER_SHAPE } from "../../src/runtime-three/player-collision";
+import {
+  resolvePlayerEdgeAssistTopOut,
+  shouldAttemptPlayerEdgeAssist
+} from "../../src/runtime-three/player-edge-assist";
+
+describe("player edge assist", () => {
+  it("only attempts edge assist for blocked airborne movement", () => {
+    expect(
+      shouldAttemptPlayerEdgeAssist({
+        enabled: true,
+        pushToTopHeight: 0.55,
+        inputMagnitude: 1,
+        requestedPlanarSpeed: 4.5,
+        planarSpeed: 0.2,
+        collisionCount: 1,
+        airborne: true
+      })
+    ).toBe(true);
+    expect(
+      shouldAttemptPlayerEdgeAssist({
+        enabled: true,
+        pushToTopHeight: 0.55,
+        inputMagnitude: 1,
+        requestedPlanarSpeed: 4.5,
+        planarSpeed: 4.5,
+        collisionCount: 0,
+        airborne: true
+      })
+    ).toBe(false);
+    expect(
+      shouldAttemptPlayerEdgeAssist({
+        enabled: true,
+        pushToTopHeight: 0.55,
+        inputMagnitude: 1,
+        requestedPlanarSpeed: 4.5,
+        planarSpeed: 0.2,
+        collisionCount: 1,
+        airborne: false
+      })
+    ).toBe(false);
+  });
+
+  it("resolves a forward and upward top-out candidate onto nearby ground", () => {
+    const topY = 1.35;
+    const result = resolvePlayerEdgeAssistTopOut({
+      feetPosition: {
+        x: 0,
+        y: 1,
+        z: 0
+      },
+      shape: FIRST_PERSON_PLAYER_SHAPE,
+      direction: {
+        x: 0,
+        y: 0,
+        z: 1
+      },
+      pushToTopHeight: 0.55,
+      canOccupyShape: (feetPosition) => feetPosition.y >= topY,
+      probeGround: (feetPosition, _shape, maxDistance) => {
+        const distance = feetPosition.y - topY;
+
+        return distance >= 0 && distance <= maxDistance
+          ? {
+              grounded: true,
+              distance,
+              normal: { x: 0, y: 1, z: 0 },
+              slopeDegrees: 0
+            }
+          : {
+              grounded: false,
+              distance: null,
+              normal: null,
+              slopeDegrees: null
+            };
+      }
+    });
+
+    expect(result).toMatchObject({
+      feetPosition: {
+        y: topY
+      }
+    });
+    expect(result?.forwardDistance).toBeGreaterThan(0);
+    expect(result?.lift).toBeCloseTo(0.35);
+  });
+
+  it("does not top out onto ground that is not above the current feet", () => {
+    const result = resolvePlayerEdgeAssistTopOut({
+      feetPosition: {
+        x: 0,
+        y: 1,
+        z: 0
+      },
+      shape: FIRST_PERSON_PLAYER_SHAPE,
+      direction: {
+        x: 0,
+        y: 0,
+        z: 1
+      },
+      pushToTopHeight: 0.55,
+      canOccupyShape: () => true,
+      probeGround: (feetPosition) => ({
+        grounded: true,
+        distance: feetPosition.y - 1,
+        normal: { x: 0, y: 1, z: 0 },
+        slopeDegrees: 0
+      })
+    });
+
+    expect(result).toBeNull();
+  });
+});