Make LUKS format resizable.

Related: #56

* Set _resizable True.
* Set up resize class.
* Fix up size tests that break when LUKS format becomes resizable.

Signed-off-by: mulhern <amulhern@redhat.com>

blivet/formats/luks.py

@@ -48,6 +48,8 @@ class LUKS(DeviceFormat):
     _minSize = crypto.LUKS_METADATA_SIZE
     _plugin = availability.BLOCKDEV_CRYPTO_PLUGIN
     _sizeinfoClass = lukstasks.LUKSSize
+    _resizeClass = lukstasks.LUKSResize
+    _resizable = True
 
     def __init__(self, **kwargs):
         """

tests/formats_test/luks_test.py

@@ -53,11 +53,14 @@ def testSize(self):
         # update the size info
         self.fmt.updateSizeInfo()
 
+        # set target size to imitate FS constructor
+        self.fmt.targetSize = self.fmt._size
+
         # the size is greater than zero and less than the size of the device
         self.assertLess(self.fmt.size, self.DEFAULT_STORE_SIZE)
         self.assertGreater(self.fmt.size, Size(0))
 
         self.assertEqual(self.fmt.currentSize, self.fmt.size)
-        self.assertEqual(self.fmt.targetSize, Size(0))
+        self.assertEqual(self.fmt.targetSize, self.fmt.size)
 
         self.fmt.teardown()