diff --git a/tests/unit/first-person-navigation-controller.test.ts b/tests/unit/first-person-navigation-controller.test.ts
index b411c480..875f7443 100644
--- a/tests/unit/first-person-navigation-controller.test.ts
+++ b/tests/unit/first-person-navigation-controller.test.ts
@@ -65,6 +65,11 @@ function createRuntimeControllerContext(
     }
   );
   const domElement = document.createElement("canvas");
+  const createVolumeState = () => ({
+    inWater: false,
+    inFog: false,
+    waterSurfaceHeight: null
+  });
 
   return {
     domElement,
@@ -92,10 +97,7 @@ function createRuntimeControllerContext(
         feetPosition: Vec3,
         shape: FirstPersonPlayerShape
       ) => options.canOccupyPlayerShape?.(feetPosition, shape) ?? true,
-      resolvePlayerVolumeState: () => ({
-        inWater: false,
-        inFog: false
-      }),
+      resolvePlayerVolumeState: () => createVolumeState(),
       resolveThirdPersonCameraCollision: (
         _pivot: Vec3,
         desiredCameraPosition: Vec3