columns: Useful __str__, __repr__ implementation

The default implementations for __str__ and __repr__ are rubbish.

  >>> from osc_lib.cli import format_columns
  >>> str(format_columns.DictColumn({'foo': 'bar'}))
  '<osc_lib.cli.format_columns.DictColumn object at 0x7f6e26771e40>'
  >>> repr(format_columns.DictColumn({'foo': 'bar'}))
  '<osc_lib.cli.format_columns.DictColumn object at 0x7f6e26b57ac0>'

Make it useful.

  >>> from osc_lib.cli import format_columns
  >>> str(format_columns.DictColumn({'foo': 'bar'}))
  "foo='bar'"
  >>> repr(format_columns.DictColumn({'foo': 'bar'}))
  "DictColumn({'foo': 'bar'})"

This helps when testing as the reason for mismatches will be more
obvious.

Change-Id: I8b8598875f896cb3dbf417515d377e7758b3b98b
Signed-off-by: Stephen Finucane <sfinucan@redhat.com>

2 files changed, 23 insertions, 3 deletions

diff --git a/cliff/columns.py b/cliff/columns.py
index b9cac5e..3462176 100644
--- a/cliff/columns.py
+++ b/cliff/columns.py
@@ -31,6 +31,12 @@ class FormattableColumn(object, metaclass=abc.ABCMeta):
             self.__class__ == other.__class__ and self._value < other._value
         )
 
+    def __str__(self):
+        return self.human_readable()
+
+    def __repr__(self):
+        return '%s(%r)' % (self.__class__.__name__, self.machine_readable())
+
     @abc.abstractmethod
     def human_readable(self):
         """Return a basic human readable version of the data."""
diff --git a/cliff/tests/test_columns.py b/cliff/tests/test_columns.py
index 6bce767..364d258 100644
--- a/cliff/tests/test_columns.py
+++ b/cliff/tests/test_columns.py
@@ -23,17 +23,31 @@ class FauxColumn(columns.FormattableColumn):
 
 class TestColumns(unittest.TestCase):
 
-    def test_faux_column_machine(self):
+    def test_machine_readable(self):
         c = FauxColumn(['list', 'of', 'values'])
         self.assertEqual(['list', 'of', 'values'], c.machine_readable())
 
-    def test_faux_column_human(self):
+    def test_human_readable(self):
         c = FauxColumn(['list', 'of', 'values'])
         self.assertEqual(
-            u"I made this string myself: ['list', 'of', 'values']",
+            "I made this string myself: ['list', 'of', 'values']",
             c.human_readable(),
         )
 
+    def test_str(self):
+        c = FauxColumn(['list', 'of', 'values'])
+        self.assertEqual(
+            "I made this string myself: ['list', 'of', 'values']",
+            str(c),
+        )
+
+    def test_repr(self):
+        c = FauxColumn(['list', 'of', 'values'])
+        self.assertEqual(
+            "FauxColumn(['list', 'of', 'values'])",
+            repr(c),
+        )
+
     def test_sorting(self):
         cols = [
             FauxColumn('foo'),