express: Implement copy.deepcopy() for PointerToArray

It actually makes a unique copy of the underlying array.

tests/express/test_pointertoarray.py

@@ -69,3 +69,63 @@ def test_cpta_float_pickle():
         data_pta2 = loads(dumps(data_pta, proto))
         assert tuple(data_pta2) == (1.0, 2.0, 3.0)
         assert data_pta2.get_data() == data_pta.get_data()
+
+
+def test_pta_float_copy():
+    from panda3d.core import PTA_float
+    from copy import copy
+
+    null_pta = PTA_float()
+    assert copy(null_pta).is_null()
+
+    empty_pta = PTA_float([])
+    empty_pta_copy = copy(empty_pta)
+    assert not empty_pta_copy.is_null()
+    assert len(empty_pta_copy) == 0
+    assert empty_pta_copy.get_ref_count() == 2
+
+    data_pta = PTA_float([1.0, 2.0, 3.0])
+    data_pta_copy = copy(data_pta)
+    assert not data_pta_copy.is_null()
+    assert data_pta_copy.get_ref_count() == 2
+    assert tuple(data_pta_copy) == (1.0, 2.0, 3.0)
+
+
+def test_pta_float_deepcopy():
+    from panda3d.core import PTA_float
+    from copy import deepcopy
+
+    null_pta = PTA_float()
+    assert deepcopy(null_pta).is_null()
+
+    empty_pta = PTA_float([])
+    empty_pta_copy = deepcopy(empty_pta)
+    assert not empty_pta_copy.is_null()
+    assert len(empty_pta_copy) == 0
+    assert empty_pta_copy.get_ref_count() == 1
+
+    data_pta = PTA_float([1.0, 2.0, 3.0])
+    data_pta_copy = deepcopy(data_pta)
+    assert not data_pta_copy.is_null()
+    assert data_pta_copy.get_ref_count() == 1
+    assert tuple(data_pta_copy) == (1.0, 2.0, 3.0)
+
+
+def test_cpta_float_deepcopy():
+    from panda3d.core import PTA_float, CPTA_float
+    from copy import deepcopy
+
+    null_pta = CPTA_float(PTA_float())
+    assert deepcopy(null_pta).is_null()
+
+    empty_pta = CPTA_float([])
+    empty_pta_copy = deepcopy(empty_pta)
+    assert not empty_pta_copy.is_null()
+    assert len(empty_pta_copy) == 0
+    assert empty_pta_copy.get_ref_count() == 1
+
+    data_pta = CPTA_float([1.0, 2.0, 3.0])
+    data_pta_copy = deepcopy(data_pta)
+    assert not data_pta_copy.is_null()
+    assert data_pta_copy.get_ref_count() == 1
+    assert tuple(data_pta_copy) == (1.0, 2.0, 3.0)