test: add quality-depth gates and mature CPU coverage

tests/conftest.py

@@ -6,7 +6,6 @@ import socket
 from unittest.mock import MagicMock
 
 import pytest
-import torch
 
 
 _EXTERNAL_MARKERS = ("network", "download", "remote")
@@ -46,6 +45,8 @@ def mock_model():
     - model.config  with config.num_hidden_layers = 4
     - model.named_parameters() returning fake weight tensors
     """
+    import torch
+
     model = MagicMock()
 
     # Config with num_hidden_layers
@@ -83,6 +84,8 @@ def mock_tokenizer():
 @pytest.fixture
 def refusal_direction():
     """A normalized random torch tensor of shape (768,)."""
+    import torch
+
     t = torch.randn(768)
     return t / t.norm()
 
@@ -90,6 +93,8 @@ def refusal_direction():
 @pytest.fixture
 def activation_pair():
     """A tuple of (harmful_activations, harmless_activations) as random tensors of shape (10, 768)."""
+    import torch
+
     harmful_activations = torch.randn(10, 768)
     harmless_activations = torch.randn(10, 768)
     return (harmful_activations, harmless_activations)