Fix some docstrings and add validation testing for deterministic.py (…

…#342)

* Add new tests for deterministicvariable

* Fix docs, error classes, and order of validation in deterministic.py

* More meaningful error message and test for it

model/src/pyrenew/deterministic/deterministic.py

@@ -40,16 +40,16 @@ def __init__(
         None
         """
         self.name = name
-        self.value = jnp.atleast_1d(value)
         self.validate(value)
+        self.value = jnp.atleast_1d(value)
         self.set_timeseries(t_start, t_unit)
 
         return None
 
     @staticmethod
     def validate(value: ArrayLike) -> None:
         """
-        Validates input to DeterministicPMF
+        Validates input to DeterministicVariable
 
         Parameters
         ----------
@@ -63,10 +63,14 @@ def validate(value: ArrayLike) -> None:
         Raises
         ------
         Exception
-            If the input value object is not a ArrayLike.
+            If the input value object is not an ArrayLike object.
         """
         if not isinstance(value, ArrayLike):
-            raise Exception("value is not a ArrayLike")
+            raise ValueError(
+                f"value {value} passed to a DeterministicVariable "
+                f"is of type {type(value).__name__}, expected "
+                "an ArrayLike object"
+            )
 
         return None
 

model/src/test/test_deterministic.py

@@ -1,7 +1,11 @@
 # numpydoc ignore=GL08
 
+import re
+
 import jax.numpy as jnp
+import numpy as np
 import numpy.testing as testing
+import pytest
 from pyrenew.deterministic import (
     DeterministicPMF,
     DeterministicProcess,
@@ -62,3 +66,49 @@ def test_deterministic():
 
     testing.assert_equal(var4()[0].value, None)
     testing.assert_equal(var5(duration=1)[0].value, None)
+
+
+def test_deterministic_validation():
+    """
+    Check that validation methods for DeterministicVariable
+    work as expected.
+    """
+    # validation should fail on construction
+    some_non_array_likes = [
+        {"a": jnp.array([1, 2.5, 3])},
+        # a valid pytree, but not an arraylike
+        "a string",
+    ]
+    some_array_likes = [
+        5,
+        -3.023523,
+        np.array([1, 3.32, 5]),
+        jnp.array([-32, 23]),
+        jnp.array(-32),
+        np.array(5),
+    ]
+
+    for non_arraylike_val in some_non_array_likes:
+        matchval = re.escape(
+            f"value {non_arraylike_val} passed to a "
+            "DeterministicVariable is of type "
+            f"{type(non_arraylike_val).__name__}, expected "
+            "an ArrayLike object"
+        )
+
+        with pytest.raises(ValueError, match=matchval):
+            # the class's validation function itself
+            # should raise an error when passed a
+            # non arraylike value
+            DeterministicVariable.validate(non_arraylike_val)
+
+        with pytest.raises(ValueError, match=matchval):
+            # validation should fail on constructor call
+            DeterministicVariable(
+                value=non_arraylike_val, name="invalid_variable"
+            )
+
+    # validation should succeed with ArrayLike
+    for arraylike_val in some_array_likes:
+        DeterministicVariable.validate(arraylike_val)
+        DeterministicVariable(value=arraylike_val, name="valid_variable")