fix lint: combine with statements

tests/test_pipeline.py

@@ -1772,3 +1772,73 @@ class TestPipelineMutation:
         result = pipeline.execute(None)
         assert result.success
         assert call_log == ["source", "display"]
+
+
+class TestAutoInjection:
+    """Tests for auto-injection of minimum capabilities."""
+
+    def setup_method(self):
+        """Reset registry before each test."""
+        StageRegistry._discovered = False
+        StageRegistry._categories.clear()
+        StageRegistry._instances.clear()
+        discover_stages()
+
+    def test_auto_injection_provides_minimum_capabilities(self):
+        """Pipeline with no stages gets minimum capabilities auto-injected."""
+        pipeline = Pipeline()
+        # Don't add any stages
+        pipeline.build(auto_inject=True)
+
+        # Should have stages for source, render, camera, display
+        assert len(pipeline.stages) > 0
+        assert "source" in pipeline.stages
+        assert "display" in pipeline.stages
+
+    def test_auto_injection_rebuilds_execution_order(self):
+        """Auto-injection rebuilds execution order correctly."""
+        pipeline = Pipeline()
+        pipeline.build(auto_inject=True)
+
+        # Execution order should be valid
+        assert len(pipeline.execution_order) > 0
+        # Source should come before display
+        source_idx = pipeline.execution_order.index("source")
+        display_idx = pipeline.execution_order.index("display")
+        assert source_idx < display_idx
+
+    def test_validation_error_after_auto_injection(self):
+        """Pipeline raises error if auto-injection fails to provide capabilities."""
+        from unittest.mock import patch
+
+        pipeline = Pipeline()
+
+        # Mock ensure_minimum_capabilities to return empty list (injection failed)
+        with (
+            patch.object(pipeline, "ensure_minimum_capabilities", return_value=[]),
+            patch.object(
+                pipeline,
+                "validate_minimum_capabilities",
+                return_value=(False, ["source"]),
+            ),
+        ):
+            # Even though injection "ran", it didn't provide the capability
+            # build() should raise StageError
+            with pytest.raises(StageError) as exc_info:
+                pipeline.build(auto_inject=True)
+
+            assert "Auto-injection failed" in str(exc_info.value)
+
+    def test_minimum_capability_removal_recovery(self):
+        """Pipeline re-injects minimum capability if removed."""
+        pipeline = Pipeline()
+        pipeline.build(auto_inject=True)
+
+        # Remove the display stage
+        pipeline.remove_stage("display", cleanup=True)
+
+        # Rebuild with auto-injection
+        pipeline.build(auto_inject=True)
+
+        # Display should be back
+        assert "display" in pipeline.stages