diff --git a/tests/modeling/test_model_components.py b/tests/modeling/test_model_components.py
index 5d8f1196..fbaff292 100644
--- a/tests/modeling/test_model_components.py
+++ b/tests/modeling/test_model_components.py
@@ -7,6 +7,7 @@
 from cities.modeling.model_components import (
     add_linear_component,
     add_logistic_component,
+    add_ratio_component,
     categorical_contribution,
     continuous_contribution,
     get_n,
@@ -195,3 +196,48 @@ def test_add_logistic_component():
     expected_probs = torch.sigmoid(expected_mean_prediction)
 
     assert torch.allclose(child_probs, expected_probs, atol=1e-6)
+
+
+
+def test_add_ratio_component():
+
+    data_plate = pyro.plate("data_plate", 3)
+
+    with pyro.poutine.trace() as tr:
+        add_ratio_component(
+            child_name="child1",
+            child_continuous_parents=mock_data_cont,
+            child_categorical_parents=mock_data_cat,
+            leeway=0.5,
+            data_plate=data_plate,
+            categorical_levels=categorical_levels
+        )
+
+    sigma_child = tr.trace.nodes["sigma_child1"]["value"]
+    mean_prediction_child = tr.trace.nodes["mean_outcome_prediction_child1"]["value"]
+    child_probs = tr.trace.nodes["child_probs_child1_child1"]["value"]
+
+    assert sigma_child.shape == torch.Size([])
+    assert mean_prediction_child.shape == torch.Size([3])
+    assert child_probs.shape == torch.Size([3])
+
+    weights_categorical = {}
+    for name in mock_data_cat.keys():
+        weights_categorical[name] = tr.trace.nodes[f"weights_categorical_{name}_child1"]["value"]
+
+    categorical_contrib = torch.zeros(3)
+    for name, tensor in mock_data_cat.items():
+        categorical_contrib += weights_categorical[name][..., tensor]
+
+    continuous_contrib = torch.zeros(3)
+    for key, value in mock_data_cont.items():
+        bias = tr.trace.nodes[f"bias_continuous_{key}_child1"]["value"]
+        weight = tr.trace.nodes[f"weight_continuous_{key}_child1"]["value"]
+        continuous_contrib += bias + weight * value
+
+    expected_mean_prediction = categorical_contrib + continuous_contrib
+
+    expected_probs = torch.sigmoid(expected_mean_prediction)
+
+    assert torch.allclose(child_probs, expected_probs, atol=1e-6)
+