test: test behavior of invalid handles in Python

modules/mol/base/tests/CMakeLists.txt

@@ -14,6 +14,7 @@ set(OST_MOL_BASE_UNIT_TESTS
   test_transfer_connectivity.cc
   test_view_op.cc
   tests.cc
+  test_invalid.py
 )
 
 if (USE_NUMPY)

modules/mol/base/tests/test_invalid.py

+import unittest
+from ost import geom, mol
+
+
+class TestInvalidHandleOrView(unittest.TestCase):
+    """ Test some basic behavior of invalid (chain|residue|atom|bond)
+    (view|handle)s. in Python. This test checks the behavior
+    of valid and IsValid() as well as presence and behavior of hash_code
+    and GetHashCode() on relevant handles."""
+
+    def setUp(self):
+        """ Setup some test data."""
+        # Create an entity with 3 atoms and 1 bond.
+        self.entity = mol.CreateEntity()
+        ed = self.entity.EditXCS()
+        ch = ed.InsertChain("A")
+        res = ed.AppendResidue(ch, "ALA")
+        self.at0 = ed.InsertAtom(res, "A", geom.Vec3(0, 0, 0))
+        self.at1 = ed.InsertAtom(res, "B", geom.Vec3(1, 0, 0))
+        self.at2 = ed.InsertAtom(res, "C", geom.Vec3(2, 0, 0))
+        ed.Connect(self.at0, self.at1)
+        ed.UpdateICS()
+        self.entity_view = self.entity.Select("cname=A")
+
+    def assertValidHandleOrView(self, x):
+        """Assertion for valid handles: valid and IsValid() are True,
+        hash_code and GetHashCode() work and return a positive integer.
+
+        This test also ensures the hash code is > 0. Although we make no
+        promise about the exact value of the hash, an earlier behavior was to
+        return a hash_code of 0 (null pointer) for some invalid handles. If you
+        get a hash code of 0, your installation of OpenStructure is most likely
+        buggy.
+
+        """
+        self.assertTrue(x.valid)
+        self.assertTrue(x.IsValid())
+        self.assertIsInstance(x.GetHashCode(), int)
+        self.assertTrue(x.hash_code, int)
+        self.assertTrue(x.GetHashCode() > 0)
+        self.assertTrue(x.hash_code > 0)
+
+    def assertInvalidHandleOrView(self, x):
+        """Assertion for invalid handles: valid and IsValid() are False,
+        hash_code and GetHashCode() raise an InvalidHandle error (which
+        is converted to an Exception in Python with a specific error
+        message).
+        """
+        self.assertFalse(x.valid)
+        self.assertFalse(x.IsValid())
+        with self.assertRaises(Exception, msg="Can not access invalid handle or view"):
+            x.hash_code
+        with self.assertRaises(Exception, msg="Can not access invalid handle or view"):
+            x.GetHashCode()
+
+    def test_InvalidChainHandle(self):
+        """ Test behavior of chain handles"""
+
+        # Valid
+        ch = self.entity.FindChain("A")
+        self.assertValidHandleOrView(ch)
+
+        # Invalid
+        ch = self.entity.FindChain("X")
+        self.assertInvalidHandleOrView(ch)
+
+    def test_InvalidChainView(self):
+        """ Test behavior of chain views"""
+
+        # Valid
+        ch = self.entity_view.FindChain("A")
+        self.assertValidHandleOrView(ch)
+
+        # Invalid
+        ch = self.entity_view.FindChain("X")
+        self.assertInvalidHandleOrView(ch)
+
+    def test_InvalidResidueHandle(self):
+        """ Test behavior of residue handles"""
+
+        # Valid
+        res = self.entity.FindResidue("A", 1)
+        self.assertValidHandleOrView(res)
+
+        # Invalid
+        res = self.entity.FindResidue("X", 1)
+        self.assertInvalidHandleOrView(res)
+
+    def test_InvalidResidueView(self):
+        """ Test behavior of residue views"""
+
+        # Valid
+        res = self.entity_view.FindResidue("A", 1)
+        self.assertValidHandleOrView(res)
+
+        # Invalid
+        res = self.entity_view.FindResidue("X", 1)
+        self.assertInvalidHandleOrView(res)
+
+    def test_InvalidAtomHandle(self):
+        """ Test behavior of atom handles"""
+
+        # Valid
+        at = self.entity.FindAtom("A", 1, "A")
+        self.assertValidHandleOrView(at)
+
+        # Invalid
+        at = self.entity.FindAtom("X", 1, "A")
+        self.assertInvalidHandleOrView(at)
+
+    def test_InvalidAtomView(self):
+        """ Test behavior of atom views"""
+
+        # Valid
+        at = self.entity_view.FindAtom("A", 1, "A")
+        self.assertValidHandleOrView(at)
+
+        # Invalid
+        at = self.entity_view.FindAtom("X", 1, "A")
+        self.assertInvalidHandleOrView(at)
+
+    def test_InvalidBondHandle(self):
+        """ Test behavior of atom handles"""
+
+        # Valid
+        bond = self.at0.FindBondToAtom(self.at1)
+        self.assertValidHandleOrView(bond)
+
+        # Invalid
+        bond = self.at0.FindBondToAtom(self.at0)
+        self.assertInvalidHandleOrView(bond)
+
+
+if __name__ == "__main__":
+    unittest.main()
+