Reject non-real wrapped Laplace rate parameters

src/pyrecest/distributions/circle/wrapped_laplace_distribution.py

@@ -1,7 +1,8 @@
 # pylint: disable=no-name-in-module,no-member
 from numbers import Integral
 
-from pyrecest.backend import all, asarray, exp, isfinite, mod, ndim, pi
+import numpy as np
+from pyrecest.backend import all, asarray, exp, isfinite, mod, ndim, pi, to_numpy
 
 from .abstract_circular_distribution import AbstractCircularDistribution
 
@@ -10,9 +11,14 @@
 
 
 def _validate_positive_scalar(value, name):
-    value = asarray(value)
-    if value.shape not in ((), (1,)):
-        raise ValueError(f"{name} must be a positive scalar.")
+    message = f"{name} must be a positive real scalar."
+    try:
+        value = asarray(value)
+        numpy_value = np.asarray(to_numpy(value))
+    except (TypeError, ValueError, RuntimeError, OverflowError) as exc:
+        raise ValueError(message) from exc
+    if numpy_value.shape not in ((), (1,)) or numpy_value.dtype.kind not in "iuf":
+        raise ValueError(message)
     if not bool(all(isfinite(value))):
         raise ValueError(f"{name} must be finite.")
     if not bool(all(value > 0.0)):

tests/distributions/test_wrapped_laplace_real_parameters.py

@@ -0,0 +1,17 @@
+import pytest
+
+from pyrecest.distributions.circle.wrapped_laplace_distribution import (
+    WrappedLaplaceDistribution,
+)
+
+
+@pytest.mark.parametrize("parameter_name", ["lambda_", "kappa_"])
+@pytest.mark.parametrize("invalid_value", [True, 1.0 + 1.0j])
+def test_wrapped_laplace_rejects_non_real_rate_parameters(
+    parameter_name, invalid_value
+):
+    parameters = {"lambda_": 2.0, "kappa_": 1.3}
+    parameters[parameter_name] = invalid_value
+
+    with pytest.raises(ValueError, match=parameter_name):
+        WrappedLaplaceDistribution(**parameters)