Merge pull request #320 from ev-br/can_cast_cmplx

ENH: add a test for can_cast(complex dtypes)

Author: ev-br

array_api_tests/test_data_type_functions.py

@@ -129,31 +129,17 @@ def test_broadcast_to(x, data):
     # TODO: test values
 
 
-@given(_from=non_complex_dtypes(), to=non_complex_dtypes(), data=st.data())
-def test_can_cast(_from, to, data):
-    from_ = data.draw(
-        st.just(_from) | hh.arrays(dtype=_from, shape=hh.shapes()), label="from_"
-    )
+@given(_from=hh.all_dtypes, to=hh.all_dtypes)
+def test_can_cast(_from, to):
+    out = xp.can_cast(_from, to)
 
-    out = xp.can_cast(from_, to)
+    expected = False
+    for other in dh.all_dtypes:
+        if dh.promotion_table.get((_from, other)) == to:
+            expected = True
+            break
 
     f_func = f"[can_cast({dh.dtype_to_name[_from]}, {dh.dtype_to_name[to]})]"
-    assert isinstance(out, bool), f"{type(out)=}, but should be bool {f_func}"
-    if _from == xp.bool:
-        expected = to == xp.bool
-    else:
-        same_family = None
-        for dtypes in [dh.all_int_dtypes, dh.real_float_dtypes, dh.complex_dtypes]:
-            if _from in dtypes:
-                same_family = to in dtypes
-                break
-        assert same_family is not None  # sanity check
-        if same_family:
-            from_min, from_max = dh.dtype_ranges[_from]
-            to_min, to_max = dh.dtype_ranges[to]
-            expected = from_min >= to_min and from_max <= to_max
-        else:
-            expected = False
     if expected:
         # cross-kind casting is not explicitly disallowed. We can only test
         # the cases where it should return True. TODO: if expected=False,