Image show: print human readable string when the virtual size is unknown

Currently, when the virtual size of an image is not known, "None" is displayed.
To a regular user, it feels like a programming error. We try and make things
clearer by using a "human readable" string instead.

Change-Id: Id7b8799356857d9bc58cc8a3677024fe1a7f4f56
Partial-Bug: #1665037

glanceclient/common/utils.py

@@ -421,6 +421,8 @@ def print_image(image_obj, human_readable=False, max_col_width=None):
     ignore = ['self', 'access', 'file', 'schema']
     image = dict([item for item in image_obj.items()
                   if item[0] not in ignore])
+    if 'virtual_size' in image:
+        image['virtual_size'] = image.get('virtual_size') or 'Not available'
     if human_readable:
         image['size'] = make_size_human_readable(image['size'])
     if str(max_col_width).isdigit():

glanceclient/tests/unit/test_utils.py

@@ -138,6 +138,44 @@ class TestUtils(testtools.TestCase):
 +--------------------------------------+--------------------------------------+
 | b8e1c57e-907a-4239-aed8-0df8e54b8d2d | ['Name1', 'Tag_123', 'veeeery long'] |
 +--------------------------------------+--------------------------------------+
+''',
+                         output_list.getvalue())
+
+    def test_print_image_virtual_size_available(self):
+        image = {'id': '42', 'virtual_size': 1337}
+        saved_stdout = sys.stdout
+        try:
+            sys.stdout = output_list = six.StringIO()
+            utils.print_image(image)
+        finally:
+            sys.stdout = saved_stdout
+
+        self.assertEqual('''\
++--------------+-------+
+| Property     | Value |
++--------------+-------+
+| id           | 42    |
+| virtual_size | 1337  |
++--------------+-------+
+''',
+                         output_list.getvalue())
+
+    def test_print_image_virtual_size_not_available(self):
+        image = {'id': '42', 'virtual_size': None}
+        saved_stdout = sys.stdout
+        try:
+            sys.stdout = output_list = six.StringIO()
+            utils.print_image(image)
+        finally:
+            sys.stdout = saved_stdout
+
+        self.assertEqual('''\
++--------------+---------------+
+| Property     | Value         |
++--------------+---------------+
+| id           | 42            |
+| virtual_size | Not available |
++--------------+---------------+
 ''',
                          output_list.getvalue())