Remove latent upscale CPU fallback

tests/test_dumas_h3_longvideos.py

@@ -1196,41 +1196,20 @@ class DumasH3LongVideosHelperTests(unittest.TestCase):
         self.assertEqual(smaller["chunk_length"], 17)
         self.assertEqual(smaller["temporal_overlap"], 0)
 
-    def test_upscale_video_model_falls_back_to_cpu_when_gpu_cannot_shrink(self):
+    def test_upscale_video_model_raises_when_gpu_cannot_shrink(self):
         latent = importlib.import_module("dumas_h3_latent_upscale")
-        calls = []
 
         original_tiled = latent._upscale_video_model_tiled
         original_shrink = latent._shrink_model_tile_param
-        original_is_available = latent.torch.cuda.is_available
-        original_empty_cache = latent.torch.cuda.empty_cache
-        original_gc_collect = latent.gc.collect
         try:
             latent._shrink_model_tile_param = lambda _param: None
-            latent.torch.cuda.is_available = lambda: True
-            latent.torch.cuda.empty_cache = lambda: None
-            latent.gc.collect = lambda: None
+            latent._upscale_video_model_tiled = lambda *_args, **_kwargs: (_ for _ in ()).throw(RuntimeError("out of memory"))
 
-            def fake_tiled(video, param):
-                calls.append(dict(param))
-                if param.get("device") == "cpu":
-                    return "ok", 8, 16
-                raise RuntimeError("out of memory")
-
-            latent._upscale_video_model_tiled = fake_tiled
-
-            result = latent.upscale_video_model("video", {"device": "cuda", "precision": "fp16"})
-
-            self.assertEqual(result, ("ok", 8, 16))
-            self.assertEqual(calls[0]["device"], "cuda")
-            self.assertEqual(calls[1]["device"], "cpu")
-            self.assertEqual(calls[1]["precision"], "fp32")
+            with self.assertRaisesRegex(RuntimeError, "H3 latent upscale exhausted its GPU spatial fallbacks"):
+                latent.upscale_video_model("video", {"device": "cuda", "precision": "fp16"})
         finally:
             latent._upscale_video_model_tiled = original_tiled
             latent._shrink_model_tile_param = original_shrink
-            latent.torch.cuda.is_available = original_is_available
-            latent.torch.cuda.empty_cache = original_empty_cache
-            latent.gc.collect = original_gc_collect
 
     def test_compose_persistent_does_not_expand_ambiguous_plural_to_full_cast(self):
         active = self.module.parse_wardrobe(