Merge Issue124 fix (#125)

* Fixed ResidueSelection iterator to include chain

* Add test for ResidueSelection iterator

src/chilife/MolSys.py

@@ -992,8 +992,8 @@ def __len__(self):
         return len(self.first_ix)
 
     def __iter__(self):
-        for resnum in self.resnums:
-            mask = self.molsys.resnums == resnum
+        for resnum, segid in zip(self.resnums, self.segids):
+            mask = (self.molsys.resnums == resnum) * (self.molsys.segids == segid)
             yield Residue(self.molsys, mask)
 
 

tests/test_MolSys.py

@@ -414,4 +414,14 @@ def test_from_atomsel():
 
     np.testing.assert_equal(new_prot.positions, atomsel.positions)
     np.testing.assert_equal(new_prot.ix + 435, atomsel.ix)
-    assert len(new_prot.trajectory) == len(atomsel.universe.trajectory)
+    assert len(new_prot.trajectory) == len(atomsel.universe.trajectory)
+
+
+def test_ResidueSelection_iter():
+    prot = MolSys.from_pdb('test_data/1a2w.pdb')
+    chain_B = prot.select_atoms('chain B')
+    for res in chain_B.residues:
+        assert res.chain == 'B'
+        assert np.all(res.atoms.chains == 'B')
+
+