ENH: Share memory of read-only intent(in) arrays. Closes #16347

1 files changed, 13 insertions, 0 deletions

diff --git a/numpy/f2py/tests/test_array_from_pyobj.py b/numpy/f2py/tests/test_array_from_pyobj.py
index 0524da342..77149e4e7 100644
--- a/numpy/f2py/tests/test_array_from_pyobj.py
+++ b/numpy/f2py/tests/test_array_from_pyobj.py
@@ -233,6 +233,7 @@ class Array:
                     order=self.intent.is_intent('c') and 'C' or 'F')
             assert_(self.pyarr.dtype == typ,
                     repr((self.pyarr.dtype, typ)))
+        self.pyarr.setflags(write=self.arr.flags['WRITEABLE'])
         assert_(self.pyarr.flags['OWNDATA'], (obj, intent))
         self.pyarr_attr = wrap.array_attrs(self.pyarr)
 
@@ -326,6 +327,18 @@ class TestSharedMemory:
             else:
                 assert_(not a.has_shared_memory(), repr(t.dtype))
 
+    @pytest.mark.parametrize('write', ['w', 'ro'])
+    @pytest.mark.parametrize('order', ['C', 'F'])
+    @pytest.mark.parametrize('inp', ['2seq', '23seq'])
+    def test_in_nocopy(self, write, order, inp):
+        """Test if intent(in) array can be passed without copies
+        """
+        seq = getattr(self, 'num' + inp)
+        obj = np.array(seq, dtype=self.type.dtype, order=order)
+        obj.setflags(write=(write == 'w'))
+        a = self.array(obj.shape, ((order=='C' and intent.in_.c) or intent.in_), obj)
+        assert a.has_shared_memory()
+
     def test_inout_2seq(self):
         obj = np.array(self.num2seq, dtype=self.type.dtype)
         a = self.array([len(self.num2seq)], intent.inout, obj)