TEST: Better warnings checks, rather than comments for future improve…

…ments

nibabel/tests/test_volumeutils.py

@@ -20,6 +20,7 @@
 import bz2
 import threading
 import time
+from packaging.version import Version
 
 import numpy as np
 
@@ -68,6 +69,8 @@
 IUINT_TYPES = INT_TYPES + np.sctypes['uint']
 NUMERIC_TYPES = CFLOAT_TYPES + IUINT_TYPES
 
+FP_RUNTIME_WARN = Version(np.__version__) >= Version('1.24.0.dev0+239')
+
 
 def test__is_compressed_fobj():
     # _is_compressed helper function
@@ -672,50 +675,45 @@ def test_a2f_nan2zero_range():
         arr = np.array([-1, 0, 1, np.nan], dtype=dt)
         # Error occurs for arrays without nans too
         arr_no_nan = np.array([-1, 0, 1, 2], dtype=dt)
-        warn_type = np.ComplexWarning if np.issubdtype(dt, np.complexfloating) else None
+        complex_warn = (np.ComplexWarning,) if np.issubdtype(dt, np.complexfloating) else ()
+        # Casting nan to int will produce a RuntimeWarning in numpy 1.24
+        nan_warn = (RuntimeWarning,) if FP_RUNTIME_WARN else ()
+        c_and_n_warn = complex_warn + nan_warn
         # No errors from explicit thresholding
         # mn thresholding excluding zero
-        with pytest.warns(warn_type) if warn_type else error_warnings():
+        with pytest.warns(complex_warn) if complex_warn else error_warnings():
             assert_array_equal([1, 1, 1, 0],
                                write_return(arr, fobj, np.int8, mn=1))
         # mx thresholding excluding zero
-        with pytest.warns(warn_type) if warn_type else error_warnings():
+        with pytest.warns(complex_warn) if complex_warn else error_warnings():
             assert_array_equal([-1, -1, -1, 0],
                                write_return(arr, fobj, np.int8, mx=-1))
         # Errors from datatype threshold after scaling
-        with pytest.warns(warn_type) if warn_type else error_warnings():
+        with pytest.warns(complex_warn) if complex_warn else error_warnings():
             back_arr = write_return(arr, fobj, np.int8, intercept=128)
         assert_array_equal([-128, -128, -127, -128], back_arr)
         with pytest.raises(ValueError):
             write_return(arr, fobj, np.int8, intercept=129)
         with pytest.raises(ValueError):
             write_return(arr_no_nan, fobj, np.int8, intercept=129)
         # OK with nan2zero false, but we get whatever nan casts to
-        with pytest.warns(warn_type) if warn_type else error_warnings():
-            # XXX NP1.24
-            # Casting nan to int will produce a RuntimeWarning in numpy 1.24
-            # Change to expecting this warning when this becomes our minimum
-            with np.errstate(invalid='ignore'):
-                nan_cast = np.array(np.nan, dtype=dt).astype(np.int8)
-        with pytest.warns(warn_type) if warn_type else error_warnings():
-            # XXX NP1.24 - expect RuntimeWarning
-            with np.errstate(invalid='ignore'):
-                back_arr = write_return(arr, fobj, np.int8, intercept=129, nan2zero=False)
+        with pytest.warns(c_and_n_warn) if c_and_n_warn else error_warnings():
+            nan_cast = np.array(np.nan, dtype=dt).astype(np.int8)
+        with pytest.warns(c_and_n_warn) if c_and_n_warn else error_warnings():
+            back_arr = write_return(arr, fobj, np.int8, intercept=129, nan2zero=False)
         assert_array_equal([-128, -128, -128, nan_cast], back_arr)
         # divslope
-        with pytest.warns(warn_type) if warn_type else error_warnings():
+        with pytest.warns(complex_warn) if complex_warn else error_warnings():
             back_arr = write_return(arr, fobj, np.int8, intercept=256, divslope=2)
         assert_array_equal([-128, -128, -128, -128], back_arr)
         with pytest.raises(ValueError):
             write_return(arr, fobj, np.int8, intercept=257.1, divslope=2)
         with pytest.raises(ValueError):
             write_return(arr_no_nan, fobj, np.int8, intercept=257.1, divslope=2)
         # OK with nan2zero false
-        with pytest.warns(warn_type) if warn_type else error_warnings():
-            # XXX NP1.24 - expect RuntimeWarning
-            with np.errstate(invalid='ignore'):
-                back_arr = write_return(arr, fobj, np.int8,
-                                        intercept=257.1, divslope=2, nan2zero=False)
+        with pytest.warns(c_and_n_warn) if c_and_n_warn else error_warnings():
+            back_arr = write_return(arr, fobj, np.int8,
+                                    intercept=257.1, divslope=2, nan2zero=False)
         assert_array_equal([-128, -128, -128, nan_cast], back_arr)