From 7a11445b3b1f0c607221ac5b56aacac74e0a35da Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Francesc=20Mart=C3=AD=20Escofet?=
 <154450563+FrancescMartiEscofetQC@users.noreply.github.com>
Date: Fri, 14 Jun 2024 12:58:48 +0200
Subject: [PATCH] Switch `strict` meaning in `validate_number_positive`

---
 metalearners/_utils.py              | 19 +++++++++++++------
 metalearners/cross_fit_estimator.py |  2 +-
 tests/test_cross_fit_estimator.py   |  4 +++-
 3 files changed, 17 insertions(+), 8 deletions(-)

diff --git a/metalearners/_utils.py b/metalearners/_utils.py
index 00eecfb..0aca691 100644
--- a/metalearners/_utils.py
+++ b/metalearners/_utils.py
@@ -1,7 +1,6 @@
 # # Copyright (c) QuantCo 2024-2024
 # # SPDX-License-Identifier: BSD-3-Clause
 
-import operator
 from collections.abc import Callable
 from inspect import signature
 from operator import le, lt
@@ -66,14 +65,22 @@ def validate_all_vectors_same_index(*args: Vector) -> None:
 
 
 def validate_number_positive(
-    value: int | float, name: str, strict: bool = False
+    value: int | float, name: str, strict: bool = True
 ) -> None:
+    """Validates that a number is positive.
+
+    If ``strict = True`` then it validates that the number is strictly positive.
+    """
     if strict:
-        comparison = operator.lt
+        if value <= 0:
+            raise ValueError(
+                f"{name} was expected to be strictly positive but was {value}."
+            )
     else:
-        comparison = operator.le
-    if comparison(value, 0):
-        raise ValueError(f"{name} was expected to be positive but was {value}.")
+        if value < 0:
+            raise ValueError(
+                f"{name} was expected to be positive or zero but was {value}."
+            )
 
 
 def check_propensity_score(
diff --git a/metalearners/cross_fit_estimator.py b/metalearners/cross_fit_estimator.py
index e26d898..9765aa7 100644
--- a/metalearners/cross_fit_estimator.py
+++ b/metalearners/cross_fit_estimator.py
@@ -56,7 +56,7 @@ def _validate_data_match_prior_split(
 ) -> None:
     """Validate whether the previous test_indices and the passed data are based on the
     same number of observations."""
-    validate_number_positive(n_observations, "n_observations", strict=False)
+    validate_number_positive(n_observations, "n_observations", strict=True)
     if test_indices is None:
         return
     expected_n_observations = sum(len(x) for x in test_indices)
diff --git a/tests/test_cross_fit_estimator.py b/tests/test_cross_fit_estimator.py
index 8e34b00..bb102c5 100644
--- a/tests/test_cross_fit_estimator.py
+++ b/tests/test_cross_fit_estimator.py
@@ -223,7 +223,9 @@ def test_crossfitestimator_n_folds_1(rng, sample_size):
 )
 def test_validate_data_match(n_observations, test_indices, success):
     if n_observations < 1:
-        with pytest.raises(ValueError, match="was expected to be positive"):
+        with pytest.raises(
+            ValueError, match=r"was expected to be (strictly )?positive"
+        ):
             _validate_data_match_prior_split(n_observations, test_indices)
         return
     if success: