TST: Fixing bug in assert near equality of float16 arrays (#10697)

3 files changed, 34 insertions, 2 deletions

diff --git a/numpy/testing/nose_tools/utils.py b/numpy/testing/nose_tools/utils.py
index 2d97b5c1e..ff3cf841c 100644
--- a/numpy/testing/nose_tools/utils.py
+++ b/numpy/testing/nose_tools/utils.py
@@ -1577,7 +1577,9 @@ def integer_repr(x):
     """Return the signed-magnitude interpretation of the binary representation of
     x."""
     import numpy as np
-    if x.dtype == np.float32:
+    if x.dtype == np.float16:
+        return _integer_repr(x, np.int16, np.int16(-2**15))
+    elif x.dtype == np.float32:
         return _integer_repr(x, np.int32, np.int32(-2**31))
     elif x.dtype == np.float64:
         return _integer_repr(x, np.int64, np.int64(-2**63))
diff --git a/numpy/testing/pytest_tools/utils.py b/numpy/testing/pytest_tools/utils.py
index 8a0eb8be3..9640d48c3 100644
--- a/numpy/testing/pytest_tools/utils.py
+++ b/numpy/testing/pytest_tools/utils.py
@@ -1619,7 +1619,9 @@ def integer_repr(x):
     """Return the signed-magnitude interpretation of the binary representation of
     x."""
     import numpy as np
-    if x.dtype == np.float32:
+    if x.dtype == np.float16:
+        return _integer_repr(x, np.int16, np.int16(-2**15))
+    elif x.dtype == np.float32:
         return _integer_repr(x, np.int32, np.int32(-2**31))
     elif x.dtype == np.float64:
         return _integer_repr(x, np.int64, np.int64(-2**63))
diff --git a/numpy/testing/tests/test_utils.py b/numpy/testing/tests/test_utils.py
index 77fb974cf..7727e552f 100644
--- a/numpy/testing/tests/test_utils.py
+++ b/numpy/testing/tests/test_utils.py
@@ -911,6 +911,34 @@ class TestArrayAlmostEqualNulp(unittest.TestCase):
         self.assertRaises(AssertionError, assert_array_almost_equal_nulp,
                           x, y, nulp)
 
+    def test_float16_pass(self):
+        nulp = 5
+        x = np.linspace(-20, 20, 50, dtype=np.float16)
+        x = np.r_[-x, x]
+
+        eps = np.finfo(x.dtype).eps
+        y = x + x*eps*nulp/2.
+        assert_array_almost_equal_nulp(x, y, nulp)
+
+        epsneg = np.finfo(x.dtype).epsneg
+        y = x - x*epsneg*nulp/2.
+        assert_array_almost_equal_nulp(x, y, nulp)
+
+    def test_float16_fail(self):
+        nulp = 5
+        x = np.linspace(-20, 20, 50, dtype=np.float16)
+        x = np.r_[-x, x]
+
+        eps = np.finfo(x.dtype).eps
+        y = x + x*eps*nulp*2.
+        self.assertRaises(AssertionError, assert_array_almost_equal_nulp,
+                          x, y, nulp)
+
+        epsneg = np.finfo(x.dtype).epsneg
+        y = x - x*epsneg*nulp*2.
+        self.assertRaises(AssertionError, assert_array_almost_equal_nulp,
+                          x, y, nulp)
+
     def test_complex128_pass(self):
         nulp = 5
         x = np.linspace(-20, 20, 50, dtype=np.float64)