TEST: Check IndexedGzipFile ArrayProxys are copied properly

nibabel/tests/test_arrayproxy.py

@@ -23,7 +23,7 @@
 from .. import __version__
 from ..arrayproxy import ArrayProxy, get_obj_dtype, is_proxy, reshape_dataobj
 from ..deprecator import ExpiredDeprecationError
-from ..nifti1 import Nifti1Header
+from ..nifti1 import Nifti1Header, Nifti1Image
 from ..openers import ImageOpener
 from ..testing import memmap_after_ufunc
 from ..tmpdirs import InTemporaryDirectory
@@ -586,3 +586,20 @@ def test_copy():
     copied = proxy.copy()
     assert islock(copied._lock)
     assert proxy._lock is copied._lock
+
+
+def test_copy_with_indexed_gzip_handle(tmp_path):
+    indexed_gzip = pytest.importorskip('indexed_gzip')
+
+    spec = ((50, 50, 50, 50), np.float32, 352, 1, 0)
+    data = np.arange(np.prod(spec[0]), dtype=spec[1]).reshape(spec[0])
+    fname = str(tmp_path / 'test.nii.gz')
+    Nifti1Image(data, np.eye(4)).to_filename(fname)
+
+    with indexed_gzip.IndexedGzipFile(fname) as fobj:
+        proxy = ArrayProxy(fobj, spec)
+        copied = proxy.copy()
+
+        assert proxy.file_like is copied.file_like
+        assert np.array_equal(proxy[0, 0, 0], copied[0, 0, 0])
+        assert np.array_equal(proxy[-1, -1, -1], copied[-1, -1, -1])