Remove unnecessary numpy import (#9798)

Fix #9726

Author: kianelbo

AUTHORS

@@ -185,6 +185,7 @@ Katerina Koukiou
 Keri Volans
 Kevin Cox
 Kevin J. Foley
+Kian Eliasi
 Kian-Meng Ang
 Kodi B. Arfer
 Kojo Idrissa

changelog/9726.bugfix.rst

@@ -0,0 +1 @@
+An unnecessary ``numpy`` import inside :func:`pytest.approx` was removed.

src/_pytest/python_api.py

@@ -319,7 +319,6 @@ def __repr__(self) -> str:
 
     def _repr_compare(self, other_side: Sequence[float]) -> List[str]:
         import math
-        import numpy as np
 
         if len(self.expected) != len(other_side):
             return [
@@ -340,7 +339,7 @@ def _repr_compare(self, other_side: Sequence[float]) -> List[str]:
                 abs_diff = abs(approx_value.expected - other_value)
                 max_abs_diff = max(max_abs_diff, abs_diff)
                 if other_value == 0.0:
-                    max_rel_diff = np.inf
+                    max_rel_diff = math.inf
                 else:
                     max_rel_diff = max(max_rel_diff, abs_diff / abs(other_value))
                 different_ids.append(i)

testing/python/approx.py

@@ -92,9 +92,7 @@ def do_assert(lhs, rhs, expected_message, verbosity_level=0):
 
 
 class TestApprox:
-    def test_error_messages(self, assert_approx_raises_regex):
-        np = pytest.importorskip("numpy")
-
+    def test_error_messages_native_dtypes(self, assert_approx_raises_regex):
         assert_approx_raises_regex(
             2.0,
             1.0,
@@ -135,6 +133,22 @@ def test_error_messages(self, assert_approx_raises_regex):
             ],
         )
 
+        # Specific test for comparison with 0.0 (relative diff will be 'inf')
+        assert_approx_raises_regex(
+            [0.0],
+            [1.0],
+            [
+                r"  comparison failed. Mismatched elements: 1 / 1:",
+                rf"  Max absolute difference: {SOME_FLOAT}",
+                r"  Max relative difference: inf",
+                r"  Index \| Obtained\s+\| Expected   ",
+                rf"\s*0\s*\| {SOME_FLOAT} \| {SOME_FLOAT} ± {SOME_FLOAT}",
+            ],
+        )
+
+    def test_error_messages_numpy_dtypes(self, assert_approx_raises_regex):
+        np = pytest.importorskip("numpy")
+
         a = np.linspace(0, 100, 20)
         b = np.linspace(0, 100, 20)
         a[10] += 0.5
@@ -175,18 +189,6 @@ def test_error_messages(self, assert_approx_raises_regex):
         )
 
         # Specific test for comparison with 0.0 (relative diff will be 'inf')
-        assert_approx_raises_regex(
-            [0.0],
-            [1.0],
-            [
-                r"  comparison failed. Mismatched elements: 1 / 1:",
-                rf"  Max absolute difference: {SOME_FLOAT}",
-                r"  Max relative difference: inf",
-                r"  Index \| Obtained\s+\| Expected   ",
-                rf"\s*0\s*\| {SOME_FLOAT} \| {SOME_FLOAT} ± {SOME_FLOAT}",
-            ],
-        )
-
         assert_approx_raises_regex(
             np.array([0.0]),
             np.array([1.0]),