Fix complex scalar checking and test_square failure

Closes gh-190

Author: rgommers

Diff for: array_api_tests/test_operators_and_elementwise_functions.py

@@ -1,6 +1,7 @@
 """
 Test element-wise functions/operators against reference implementations.
 """
+import cmath
 import math
 import operator
 from copy import copy
@@ -67,6 +68,29 @@ def isclose(
     return math.isclose(a, b, rel_tol=rel_tol, abs_tol=abs_tol)
 
 
+def isclose_complex(
+    a: complex,
+    b: complex,
+    M: float,
+    *,
+    rel_tol: float = 0.25,
+    abs_tol: float = 1,
+) -> bool:
+    """Wraps math.isclose with very generous defaults.
+
+    This is useful for many floating-point operations where the spec does not
+    make accuracy requirements.
+    """
+    if cmath.isnan(a) or cmath.isnan(b):
+        raise ValueError(f"{a=} and {b=}, but input must be non-NaN")
+    if cmath.isinf(a):
+        return cmath.isinf(b) or abs(b) > cmath.log(M)
+    elif cmath.isinf(b):
+        return cmath.isinf(a) or abs(a) > cmath.log(M)
+    return cmath.isclose(a, b, rel_tol=rel_tol, abs_tol=abs_tol)
+
+
+
 def default_filter(s: Scalar) -> bool:
     """Returns False when s is a non-finite or a signed zero.
 
@@ -254,8 +278,7 @@ def unary_assert_against_refimpl(
                 f"{f_i}={scalar_i}"
             )
             if res.dtype in dh.complex_dtypes:
-                assert isclose(scalar_o.real, expected.real, M), msg
-                assert isclose(scalar_o.imag, expected.imag, M), msg
+                assert isclose_complex(scalar_o, expected, M), msg
             else:
                 assert isclose(scalar_o, expected, M), msg
         else:
@@ -330,8 +353,7 @@ def binary_assert_against_refimpl(
                 f"{f_l}={scalar_l}, {f_r}={scalar_r}"
             )
             if res.dtype in dh.complex_dtypes:
-                assert isclose(scalar_o.real, expected.real, M), msg
-                assert isclose(scalar_o.imag, expected.imag, M), msg
+                assert isclose_complex(scalar_o, expected, M), msg
             else:
                 assert isclose(scalar_o, expected, M), msg
         else:
@@ -403,8 +425,7 @@ def right_scalar_assert_against_refimpl(
                 f"{f_l}={scalar_l}"
             )
             if res.dtype in dh.complex_dtypes:
-                assert isclose(scalar_o.real, expected.real, M), msg
-                assert isclose(scalar_o.imag, expected.imag, M), msg
+                assert isclose_complex(scalar_o, expected, M), msg
             else:
                 assert isclose(scalar_o, expected, M), msg
         else:
@@ -1394,7 +1415,7 @@ def test_square(x):
     ph.assert_dtype("square", in_dtype=x.dtype, out_dtype=out.dtype)
     ph.assert_shape("square", out_shape=out.shape, expected=x.shape)
     unary_assert_against_refimpl(
-        "square", x, out, lambda s: s**2, expr_template="{}²={}"
+        "square", x, out, lambda s: s*s, expr_template="{}²={}"
     )