Merge branch 'spacegroup-representation'

Add `repr()` support for the SpaceGroup class (Håkon Wiik Ånes).

Close #45.

Author: pavoljuhas

CHANGELOG.md

@@ -1,5 +1,20 @@
 # Release notes
 
+## Unreleased - Version 3.0.2
+
+### Added
+
+- A string representation of `SpaceGroup` with key information.
+
+### Changed
+
+### Deprecated
+
+### Removed
+
+### Fixed
+
+
 ## Version 3.0.1 – 2019-06-27
 
 ### Added

src/diffpy/structure/spacegroupmod.py

@@ -262,6 +262,19 @@ def __init__(self,
         self.pdb_name                = pdb_name
         self.symop_list              = symop_list
 
+    def __repr__(self):
+        """Return a string representation of the space group."""
+        return (
+                   "SpaceGroup #%i (%s, %s). Symmetry matrices: %i, "
+                   "point sym. matr.: %i"
+               ) % (
+            self.number,
+            self.short_name,
+            self.crystal_system[0] + self.crystal_system[1:].lower(),
+            self.num_sym_equiv,
+            self.num_primitive_sym_equiv,
+        )
+
 
     def iter_symops(self):
         """Iterate over all symmetry operations in the space group.

src/diffpy/structure/tests/testspacegroups.py

@@ -86,6 +86,44 @@ def test__hashSymOpList(self):
         self.assertEqual(len(SpaceGroupList), len(hset))
         return
 
+    def test_spacegroup_representation(self):
+        """Verify SpaceGroup.__repr__()."""
+        self.assertEqual(
+            repr(GetSpaceGroup(1)),
+            "SpaceGroup #1 (P1, Triclinic). Symmetry matrices: 1, point sym. matr.: 1"
+        )
+        self.assertEqual(
+            repr(GetSpaceGroup(3)),
+            "SpaceGroup #3 (P2, Monoclinic). Symmetry matrices: 2, point sym. matr.: 2"
+        )
+        self.assertEqual(
+            repr(GetSpaceGroup(16)),
+            (
+                "SpaceGroup #16 (P222, Orthorhombic). Symmetry matrices: 4, point sym. "
+                "matr.: 4"
+            )
+        )
+        self.assertEqual(
+            repr(GetSpaceGroup(75)),
+            "SpaceGroup #75 (P4, Tetragonal). Symmetry matrices: 4, point sym. matr.: 4"
+        )
+        self.assertEqual(
+            repr(GetSpaceGroup(143)),
+            "SpaceGroup #143 (P3, Trigonal). Symmetry matrices: 3, point sym. matr.: 3"
+        )
+        self.assertEqual(
+            repr(GetSpaceGroup(168)),
+            "SpaceGroup #168 (P6, Hexagonal). Symmetry matrices: 6, point sym. matr.: 6"
+        )
+        self.assertEqual(
+            repr(GetSpaceGroup(229)),
+            (
+                "SpaceGroup #229 (Im-3m, Cubic). Symmetry matrices: 96, point sym. "
+                "matr.: 48"
+            )
+        )
+        return
+
 # End of class TestRoutines
 
 # ----------------------------------------------------------------------------