move stack serialization test to tests/ folder, out of source tree

tests/refl1d/stack_test.py

@@ -0,0 +1,36 @@
+from refl1d.names import Slab, Stack, SLD
+from copy import deepcopy
+from bumps.serialize import serialize, deserialize
+import pickle
+import dill
+
+
+def test_stack_serialization():
+    """test that stack can be serialized and deserialized with all the methods we use,
+    preserving the functioning of the Calculation object for the total thickness"""
+    sample = Slab(SLD(rho=10), thickness=10) | Slab(SLD(rho=10), thickness=20) | Slab(SLD(rho=10), thickness=30)
+    thickness_plus = sample.thickness + 100  # expression
+
+    ser_t, ser_s = deserialize(serialize([thickness_plus, sample]))
+    assert ser_t.value == 160
+    ser_s[0].thickness.value += 40
+    assert ser_t.value == 200
+
+    dc_t, dc_s = deepcopy([thickness_plus, sample])
+    assert dc_t.value == 160
+    dc_s[0].thickness.value += 40
+    assert dc_t.value == 200
+
+    pickle_t, pickle_s = pickle.loads(pickle.dumps([thickness_plus, sample]))
+    assert pickle_t.value == 160
+    pickle_s[0].thickness.value += 40
+    assert pickle_t.value == 200
+
+    dill_t, dill_s = dill.loads(dill.dumps([thickness_plus, sample]))
+    assert dill_t.value == 160
+    dill_s[0].thickness.value += 40
+    assert dill_t.value == 200
+
+    assert thickness_plus.value == 160
+    sample[0].thickness.value += 40
+    assert thickness_plus.value == 200