TST: add NEP 50 examples as a test

Author: ev-br

autogen/gen_dtypes.py

@@ -8,6 +8,7 @@
 import numpy as np
 import torch
 
+np._set_promotion_state("weak")
 
 class dtype:
     def __init__(self, name):

torch_np/tests/test_nep50_examples.py

@@ -0,0 +1,54 @@
+
+from torch_np import array, uint8, int64, float32, float64, inf
+from torch_np.testing import assert_allclose
+uint16 = uint8   # can be anything here, see below
+
+
+#from numpy import array, uint8, uint16, int64, float32, float64, inf
+#from numpy.testing import assert_allclose
+#import numpy as np
+#np._set_promotion_state('weak')
+
+import pytest
+from pytest import raises as assert_raises
+
+unchanged = None
+
+# expression    old result   new_result
+# uint8(1) + 2  int64(3)   uint8(3) [T1]
+examples = {"uint8(1) + 2": (int64(3), uint8(3)),
+            "array([1], uint8) + int64(1)": (array([2], uint8), array([2], int64)),
+            "array([1], uint8) + array(1, int64)": (array([2], uint8),   array([2], int64)),
+            "array([1.], float32) + float64(1.)": (array([2.], float32),   array([2.], float64)),
+            "array([1.], float32) + array(1., float64)": (array([2.], float32),   array([2.], float64)),
+            "array([1], uint8) + 1": (array([2], uint8),   unchanged),
+            "array([1], uint8) + 200": (array([201], uint8), unchanged),
+            "array([100], uint8) + 200": (array([ 44], uint8),  unchanged),
+            "array([1], uint8) + 300":  (array([301], uint16),  Exception),
+            "uint8(1) + 300": (int64(301),            Exception),
+            "uint8(100) + 200": (int64(301),            uint8(44)),   # and RuntimeWarning
+            "float32(1) + 3e100" : (float64(3e100),        float32(inf)), # and RuntimeWarning [T7]
+      #      "array([0.1], float32) == 0.1": (array([False]),      unchanged),         # XXX: a typo in NEP50?
+            "array([0.1], float32) == float64(0.1)": (array([ True]), array([False])),
+            "array([1.], float32) + 3": (array([4.], float32),     unchanged),
+            "array([1.], float32) + int64(3)": (array([4.], float32),   array([4.], float64))
+}
+
+
+@pytest.mark.parametrize("example", examples)
+def test_nep50_exceptions(example):
+    old, new = examples[example]
+
+    if new == Exception:
+        with assert_raises(OverflowError):
+            eval(example)
+
+    else:
+        result = eval(example)
+
+        if new is unchanged:
+            new = old
+
+        assert_allclose(result, new, atol=1e-16)
+        assert result.dtype == new.dtype
+