Linear regression component tests (#1715)

* change the lookup name

* add additional tests for linear regression components

Author: williambdean

pymc_marketing/mmm/components/adstock.py

@@ -55,6 +55,7 @@ def function(self, x, alpha):
 from __future__ import annotations
 
 import numpy as np
+import pytensor.tensor as pt
 import xarray as xr
 from pydantic import Field, validate_call
 
@@ -336,7 +337,7 @@ class NoAdstock(AdstockTransformation):
 
     def function(self, x):
         """No adstock function."""
-        return x
+        return pt.as_tensor_variable(x)
 
     default_priors = {}
 

pymc_marketing/mmm/components/saturation.py

@@ -481,7 +481,7 @@ class NoSaturation(SaturationTransformation):
 
     """
 
-    lookup_name = "linear"
+    lookup_name = "no_saturation"
 
     def function(self, x, beta):
         """Linear saturation function."""

tests/mmm/components/test_adstock.py

@@ -29,6 +29,7 @@
     AdstockTransformation,
     DelayedAdstock,
     GeometricAdstock,
+    NoAdstock,
     WeibullCDFAdstock,
     WeibullPDFAdstock,
     adstock_from_dict,
@@ -45,6 +46,7 @@ def adstocks() -> list:
             GeometricAdstock(l_max=10),
             WeibullPDFAdstock(l_max=10),
             WeibullCDFAdstock(l_max=10),
+            NoAdstock(l_max=1),
         ]
 
     return [
@@ -101,6 +103,9 @@ def test_adstock_no_negative_lmax():
     adstocks(),
 )
 def test_adstock_sample_curve(adstock) -> None:
+    if adstock.lookup_name == "no_adstock":
+        raise pytest.skip(reason="NoAdstock has no parameters to sample.")
+
     prior = adstock.sample_prior()
     assert isinstance(prior, xr.Dataset)
     curve = adstock.sample_curve(prior)

tests/mmm/components/test_saturation.py

@@ -31,6 +31,7 @@
     InverseScaledLogisticSaturation,
     LogisticSaturation,
     MichaelisMentenSaturation,
+    NoSaturation,
     RootSaturation,
     SaturationTransformation,
     TanhSaturation,
@@ -56,6 +57,7 @@ def saturation_functions():
         HillSaturation(),
         HillSaturationSigmoid(),
         RootSaturation(),
+        NoSaturation(),
     ]
     return [
         pytest.param(transformation, id=transformation.lookup_name)