diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
new file mode 100644
index 0000000..48adc9c
--- /dev/null
+++ b/.github/workflows/test.yml
@@ -0,0 +1,29 @@
+name: Tests
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+
+jobs:
+  pytest:
+    name: pytest (Python ${{ matrix.python-version }})
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        python-version: ["3.10", "3.11", "3.12"]
+    steps:
+      - name: Check out code
+        uses: actions/checkout@v4
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: ${{ matrix.python-version }}
+      - name: Install test dependencies
+        # comfy_api is mocked in conftest.py, so a full ComfyUI install isn't needed.
+        # numpy silences torch's "Failed to initialize NumPy" import warning.
+        run: python -m pip install --upgrade pip pytest torch numpy
+      - name: Run tests
+        run: python -m pytest -q
diff --git a/nodes.py b/nodes.py
index d9dd8e1..50b4ec6 100644
--- a/nodes.py
+++ b/nodes.py
@@ -393,6 +393,29 @@ class ConstrainResolution(io.ComfyNode):
             width, height, min_res, max_res, multiple_of, constraint_mode
         )
 
+        # Degenerate input (empty/malformed tensor) collapses to a 0 target,
+        # which would crash the resizer. Pass the image through untouched instead.
+        if target_width == 0 or target_height == 0:
+            logger.warning(
+                "Input has a zero dimension (%dx%d); passing image through unchanged.",
+                width, height
+            )
+            return io.NodeOutput(
+                image, image, width, height,
+                original_aspect_ratio, original_aspect_ratio
+            )
+
+        # Warn when Prioritize Min Resolution forces a large upscale (extreme aspect
+        # ratios can blow up the long side and risk OOM). Strict mode caps this instead.
+        if constraint_mode == ConstraintMode.MIN_RES.value:
+            upscale_factor = max(target_width / width, target_height / height)
+            if upscale_factor > 4:
+                logger.warning(
+                    "Upscaling by %.1fx to %dx%d to satisfy min_res on an extreme aspect ratio. "
+                    "Use 'Prioritize Max Resolution (Strict)' to cap output size and avoid large upscales.",
+                    upscale_factor, target_width, target_height
+                )
+
         # Resize image to target dimensions
         resized_image = cls.resize_image(image, target_width, target_height, resize_method)
 
diff --git a/tests/test_nodes.py b/tests/test_nodes.py
index 6ae40bd..126ccb7 100644
--- a/tests/test_nodes.py
+++ b/tests/test_nodes.py
@@ -180,3 +180,27 @@ class TestCropImage:
         image = torch.rand(1, 120, 200, 3)
         out = ConstrainResolution.crop_image(image, 100, 100, position)
         assert out.shape == (1, 100, 100, 3)
+
+
+class TestExecuteGuards:
+    def test_zero_dimension_input_passes_through(self):
+        """A malformed tensor with a zero dimension must pass through, not crash the resizer."""
+        image = torch.rand(1, 0, 500, 3)
+        resized, original, out_w, out_h, _, _ = run_node(image)
+        assert resized.shape == image.shape
+        assert original.shape == image.shape
+        assert (out_w, out_h) == (500, 0)
+
+    def test_extreme_ratio_min_res_warns(self, caplog):
+        """Extreme aspect ratio in MIN_RES mode should warn about the large upscale."""
+        image = torch.rand(1, 100, 1000, 3)
+        with caplog.at_level("WARNING"):
+            run_node(image, constraint_mode=MIN)
+        assert any("Upscaling by" in r.message for r in caplog.records)
+
+    def test_normal_image_does_not_warn(self, caplog):
+        """A normal image must not trigger the upscale warning."""
+        image = torch.rand(1, 800, 1000, 3)
+        with caplog.at_level("WARNING"):
+            run_node(image, constraint_mode=MIN)
+        assert not any("Upscaling by" in r.message for r in caplog.records)