num_causal

Detect num_causal error in sim_trait function

tests/test_sim_trait.py

@@ -49,6 +49,17 @@ def test_bad_input(self, sample_ts, sample_trait_model):
                 ts=sample_ts, num_causal=num_causal, model=sample_trait_model
             )
 
+    @pytest.mark.parametrize("num_causal", [0, -1])
+    def test_num_causal_input(self, sample_ts, sample_trait_model, num_causal):
+        with pytest.raises(TypeError, match="num_causal must be an integer"):
+            tstrait.sim_trait(ts=sample_ts, num_causal=1.0, model=sample_trait_model)
+        with pytest.raises(
+            ValueError, match="num_causal must be an integer not less than 1"
+        ):
+            tstrait.sim_trait(
+                ts=sample_ts, num_causal=num_causal, model=sample_trait_model
+            )
+
 
 class TestOutputDim:
     """Check that the sim_trait function gives the correct output regardless of the

tstrait/simulate_effect_size.py

@@ -4,6 +4,7 @@
 import tstrait
 
 from .base import _check_instance
+from .base import _check_int
 
 
 class _TraitSimulator:
@@ -120,6 +121,7 @@ def sim_trait(ts, num_causal, model, random_seed=None):
     """
     ts = _check_instance(ts, "ts", tskit.TreeSequence)
     model = _check_instance(model, "model", tstrait.TraitModel)
+    num_causal = _check_int(num_causal, "num_causal", minimum=1)
     num_sites = ts.num_sites
     if num_sites == 0:
         raise ValueError("No mutation in the tree sequence input")