TST: add a test for __dlpack__ dunder

Author: ev-br

array_api_tests/test_dlpack.py

@@ -76,3 +76,38 @@ def test_from_dlpack(x, copy_kw, data):
     except Exception as exc:
         ph.add_note(exc, repro_snippet)
         raise
+
+
+@given(
+    x=hh.arrays(dtype=hh.all_dtypes, shape=hh.shapes(min_dims=1, max_side=2)),
+    copy_kw=hh.kwargs(
+        copy=st.booleans() | st.none()
+    ),
+    max_version_kw=hh.kwargs(
+        max_version=st.tuples(   # XXX: limits for versions: is (-111, 42) okay?
+            st.integers(),
+            st.integers()
+        )
+    ),
+    dl_device_kw=hh.kwargs(
+        dl_device=st.tuples(  # XXX: the 2023.12 standard only mandates ... kDLCPU ?
+            st.just(DLPackDeviceEnum.CPU.value),
+            st.just(0)
+        )
+    ),
+    data=st.data()
+)
+def test_dunder_dlpack(x, copy_kw, max_version_kw, dl_device_kw, data):
+
+    repro_snippet = ph.format_snippet(
+        f"x.__dlpack__ with {copy_kw = }, {max_version_kw = } and {dl_device_kw = }"
+    )
+
+    try:
+        capsule = x.__dlpack__(**copy_kw, **max_version_kw, **dl_device_kw)
+
+        # XXX: bug or feature? np.from_dlpack(x.__dlpack__(max_version=(0, 1))) -> AttributeError
+        y = xp.from_dlpack(capsule)
+    except Exception as exc:
+        ph.add_note(exc, repro_snippet)
+        raise