TEST: Add fixture for relaxing digit limits

Author: effigies

nibabel/conftest.py

@@ -1,3 +1,5 @@
+import sys
+
 import numpy as np
 import pytest
 
@@ -12,3 +14,18 @@ def legacy_printoptions():
 
     if Version(np.__version__) >= Version('1.22'):
         np.set_printoptions(legacy='1.21')
+
+
+@pytest.fixture
+def max_digits():
+    # Set maximum number of digits for int/str conversion for
+    # duration of a test
+    try:
+        orig_max_str_digits = sys.get_int_max_str_digits()
+        yield sys.set_int_max_str_digits
+        sys.set_int_max_str_digits(orig_max_str_digits)
+    except AttributeError:
+        # Nothing to do for versions of Python that lack these methods
+        # They were added as DoS protection in Python 3.11 and backported to
+        # some other versions.
+        yield lambda x: None

nibabel/tests/test_floating.py

@@ -172,7 +172,9 @@ def test_floor_exact_64():
         assert floor_exact(test_val, np.float64) == 2 ** (e + 1) - int(gap)
 
 
-def test_floor_exact():
+def test_floor_exact(max_digits):
+    max_digits(4950)  # max longdouble is ~10**4932
+
     to_test = IEEE_floats + [float]
     try:
         type_info(np.longdouble)['nmant']
@@ -188,11 +190,11 @@ def test_floor_exact():
     for t in to_test:
         # A number bigger than the range returns the max
         info = type_info(t)
-        assert floor_exact(2**5000, t) == np.inf
-        assert ceil_exact(2**5000, t) == np.inf
+        assert floor_exact(10**4933, t) == np.inf
+        assert ceil_exact(10**4933, t) == np.inf
         # A number more negative returns -inf
-        assert floor_exact(-(2**5000), t) == -np.inf
-        assert ceil_exact(-(2**5000), t) == -np.inf
+        assert floor_exact(-(10**4933), t) == -np.inf
+        assert ceil_exact(-(10**4933), t) == -np.inf
         # Check around end of integer precision
         nmant = info['nmant']
         for i in range(nmant + 1):