WIP: add a basic test of isin

array_api_tests/_array_module.py

@@ -35,6 +35,8 @@ def __repr__(self):
 _funcs += ["take", "isdtype", "conj", "imag", "real"]  # TODO: bump spec and update array-api-tests to new spec layout
 _top_level_attrs = _dtypes + _constants + _funcs + stubs.EXTENSIONS + ["fft"]
 
+_top_level_attrs += ['isin']    # FIXME: until the spec is not updated
+
 for attr in _top_level_attrs:
     try:
         globals()[attr] = getattr(xp, attr)

array_api_tests/test_set_functions.py

@@ -5,6 +5,7 @@
 
 import pytest
 from hypothesis import assume, given
+from hypothesis import strategies as st
 
 from . import _array_module as xp
 from . import dtype_helpers as dh
@@ -256,3 +257,51 @@ def test_unique_values(x):
     except Exception as exc:
         ph.add_note(exc, repro_snippet)
         raise
+
+
+@given(
+    hh.arrays(dtype=hh.all_int_dtypes, shape=hh.shapes()),
+    hh.arrays(dtype=hh.all_int_dtypes, shape=hh.shapes()),
+    hh.kwargs(invert=st.booleans())
+)
+def test_isin(x1, x2, kw):
+  #  print("\nx1 = ", type(x1))
+    print(x1.shape, x2.shape,  x1.dtype, x2.dtype, kw)
+
+    # uint64 promotion with signed integers is prohibited in the spec, but many
+    # array libraries allow it in an implementation-defined way
+    is_mixed_int_promotion = (
+        (x1.dtype == xp.uint64 and x2.dtype in dh.int_dtypes) or
+        (x2.dtype == xp.uint64 and x1.dtype in dh.int_dtypes)
+    )
+    assume(not is_mixed_int_promotion)
+
+    repro_snippet = ph.format_snippet(f"xp.isin({x1!r}, {x2!r}, **kw) with {kw = }")
+    try:
+        out = xp.isin(x1, x2, **kw)
+
+        assert out.dtype == xp.bool
+        assert out.shape == x1.shape
+        # TODO value tests
+    except Exception as exc:
+        ph.add_note(exc, repro_snippet)
+        raise
+
+
+@given(
+    x1x2=hh.array_and_py_scalar(dh.int_dtypes),
+    kw=hh.kwargs(invert=st.booleans())
+)
+def test_isin_scalars(x1x2, kw):
+    x1, x2 = x1x2
+
+    repro_snippet = ph.format_snippet(f"xp.isin({x1!r}, {x2!r}, **kw) with {kw = }")
+    try:
+        out = xp.isin(x1, x2, **kw)
+
+        assert out.dtype == xp.bool
+        assert out.shape == () if isinstance(x1, bool | int | float | complex) else x1.shape
+        # TODO value tests
+    except Exception as exc:
+        ph.add_note(exc, repro_snippet)
+        raise