From 4ba25b631573a8d43f56a5385b00d161e62e6568 Mon Sep 17 00:00:00 2001
From: Evgeni Burovski <evgeny.burovskiy@gmail.com>
Date: Sun, 11 Jan 2026 15:12:51 +0100
Subject: [PATCH 1/2] ENH: add a basic test of isin

---
 array_api_tests/_array_module.py      |  2 ++
 array_api_tests/test_set_functions.py | 21 +++++++++++++++++++++
 2 files changed, 23 insertions(+)

diff --git a/array_api_tests/_array_module.py b/array_api_tests/_array_module.py
index 1c52a983..96d0d452 100644
--- a/array_api_tests/_array_module.py
+++ b/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)
diff --git a/array_api_tests/test_set_functions.py b/array_api_tests/test_set_functions.py
index 8a6f7a9d..d72fb1e5 100644
--- a/array_api_tests/test_set_functions.py
+++ b/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 +257,23 @@ def test_unique_values(x):
     except Exception as exc:
         ph.add_note(exc, repro_snippet)
         raise
+
+
+@given(
+    *hh.two_mutual_arrays(two_shapes=st.tuples(hh.shapes(), 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)
+
+    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

From 3db170a63a88a5eefea39f4fab4bb804416c9015 Mon Sep 17 00:00:00 2001
From: Evgeni Burovski <evgeny.burovskiy@gmail.com>
Date: Sun, 11 Jan 2026 15:53:30 +0100
Subject: [PATCH 2/2] ENH: add test for isin with scalars

---
 array_api_tests/test_set_functions.py | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/array_api_tests/test_set_functions.py b/array_api_tests/test_set_functions.py
index d72fb1e5..b349c500 100644
--- a/array_api_tests/test_set_functions.py
+++ b/array_api_tests/test_set_functions.py
@@ -277,3 +277,22 @@ def test_isin(x1, x2, kw):
     except Exception as exc:
         ph.add_note(exc, repro_snippet)
         raise
+
+
+@given(
+    x1x2=hh.array_and_py_scalar(dh.all_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