ENH: unstructured_to_structured converts dtype argument (#22442)

Before:

>>> field = unstructured_to_structured(np.zeros((20, 2)), dtype=[('x', float), ('y', float)]) # failed
>>> field = unstructured_to_structured(np.zeros((20, 2)), dtype=np.dtype([('x', float), ('y', float)])) # success
After:

>>> field = unstructured_to_structured(np.zeros((20, 2)), dtype=[('x', float), ('y', float)]) # success
>>> field = unstructured_to_structured(np.zeros((20, 2)), dtype=np.dtype([('x', float), ('y', float)])) # success

Closes gh-22428

1 files changed, 9 insertions, 0 deletions

diff --git a/numpy/lib/tests/test_recfunctions.py b/numpy/lib/tests/test_recfunctions.py
index 9b2506a7c..d8385f8be 100644
--- a/numpy/lib/tests/test_recfunctions.py
+++ b/numpy/lib/tests/test_recfunctions.py
@@ -318,6 +318,15 @@ class TestRecFunctions:
         assert_raises(NotImplementedError, unstructured_to_structured,
                                            np.zeros((3,0), dtype=np.int32))
 
+    def test_unstructured_to_structured(self):
+        # test if dtype is the args of np.dtype
+        a = np.zeros((20, 2))
+        test_dtype_args = [('x', float), ('y', float)]
+        test_dtype = np.dtype(test_dtype_args)
+        field1 = unstructured_to_structured(a, dtype=test_dtype_args)  # now
+        field2 = unstructured_to_structured(a, dtype=test_dtype)  # before
+        assert_equal(field1, field2)
+
     def test_field_assignment_by_name(self):
         a = np.ones(2, dtype=[('a', 'i4'), ('b', 'f8'), ('c', 'u1')])
         newdt = [('b', 'f4'), ('c', 'u1')]