Change: Tags has ordered list of tags

3 files changed, 84 insertions, 53 deletions

diff --git a/vmdb/__init__.py b/vmdb/__init__.py
index 2bcc954..91aa015 100644
--- a/vmdb/__init__.py
+++ b/vmdb/__init__.py
@@ -31,7 +31,7 @@ from .runcmd import (
     progress,
     error,
 )
-from .tags import Tags, UnknownTag, TagInUse, AlreadyMounted
+from .tags import Tags, UnknownTag, TagInUse, AlreadyHasDev, AlreadyMounted
 from .unmount import unmount, NotMounted
 from .spec import (
     Spec,
diff --git a/vmdb/tags.py b/vmdb/tags.py
index 2318a65..337b36d 100644
--- a/vmdb/tags.py
+++ b/vmdb/tags.py
@@ -29,6 +29,7 @@ class Tags:
 
     def __init__(self):
         self._tags = {}
+        self._tagnames = []
 
     def get_tags(self):
         return list(self._tags.keys())
@@ -37,35 +38,39 @@ class Tags:
         return tag in self._tags
 
     def get_dev(self, tag):
-        item = self._tags.get(tag)
-        if item is None:
-            raise UnknownTag(tag)
+        item = self._get(tag)
         return item['dev']
 
     def get_mount_point(self, tag):
-        item = self._tags.get(tag)
-        if item is None:
-            raise UnknownTag(tag)
+        item = self._get(tag)
         return item['mount_point']
 
-    def add_partition(self, tag, dev):
+    def append(self, tag):
         if tag in self._tags:
             raise TagInUse(tag)
-        self._new(tag, dev, None)
+        self._tagnames.append(tag)
+        self._tags[tag] = {
+            'dev': None,
+            'mount_point': None,
+        }
 
-    def add_mount_point(self, tag, mount_point):
-        item = self._tags.get(tag)
-        if item is None:
-            raise UnknownTag(tag)
+    def set_dev(self, tag, dev):
+        item = self._get(tag)
+        if item['dev'] is not None:
+            raise AlreadyHasDev(tag)
+        item['dev'] = dev
+
+    def set_mount_point(self, tag, mount_point):
+        item = self._get(tag)
         if item['mount_point'] is not None:
             raise AlreadyMounted(tag)
         item['mount_point'] = mount_point
 
-    def _new(self, tag, dev, mount_point):
-        self._tags[tag] = {
-            'dev': dev,
-            'mount_point': mount_point,
-        }
+    def _get(self, tag):
+        item = self._tags.get(tag)
+        if item is None:
+            raise UnknownTag(tag)
+        return item
 
 
 class TagInUse(Exception):
@@ -80,6 +85,12 @@ class UnknownTag(Exception):
         super().__init__('Unknown tag: {}'.format(tag))
 
 
+class AlreadyHasDev(Exception):
+
+    def __init__(self, tag):
+        super().__init__('Already has device: {}'.format(tag))
+
+
 class AlreadyMounted(Exception):
 
     def __init__(self, tag):
diff --git a/vmdb/tags_tests.py b/vmdb/tags_tests.py
index ae20e38..ff960b7 100644
--- a/vmdb/tags_tests.py
+++ b/vmdb/tags_tests.py
@@ -22,57 +22,77 @@ import unittest
 import vmdb
 
 
-class ImageTests(unittest.TestCase):
+class TagsTests(unittest.TestCase):
 
     def test_lists_not_tags_initally(self):
-        image = vmdb.Image()
-        self.assertEqual(image.get_tags(), [])
+        tags = vmdb.Tags()
+        self.assertEqual(tags.get_tags(), [])
 
     def test_tells_if_tag_is_used(self):
-        image = vmdb.Image()
-        self.assertFalse(image.has_tag('foo'))
-        image.add_partition('foo', 'bar')
-        self.assertTrue(image.has_tag('foo'))
+        tags = vmdb.Tags()
+        self.assertFalse(tags.has_tag('foo'))
+        tags.append('foo')
+        self.assertTrue(tags.has_tag('foo'))
+        self.assertEqual(tags.get_tags(), ['foo'])
+
+    def test_remembers_order(self):
+        tags = vmdb.Tags()
+        tags.append('foo')
+        tags.append('bar')
+        self.assertTrue(tags.get_tags(), ['foo', 'bar'])
 
     def test_get_dev_raises_error_for_unknown_tag(self):
-        image = vmdb.Image()
+        tags = vmdb.Tags()
         with self.assertRaises(vmdb.UnknownTag):
-            image.get_dev('does-not-exist')
+            tags.get_dev('does-not-exist')
 
     def test_get_mount_point_raises_error_for_unknown_tag(self):
-        image = vmdb.Image()
+        tags = vmdb.Tags()
         with self.assertRaises(vmdb.UnknownTag):
-            image.get_mount_point('does-not-exist')
+            tags.get_mount_point('does-not-exist')
 
     def test_raises_error_for_reused_tag(self):
-        image = vmdb.Image()
-        image.add_partition('tag', 'dev')
+        tags = vmdb.Tags()
+        tags.append('tag')
         with self.assertRaises(vmdb.TagInUse):
-            image.add_partition('tag', 'dev')
+            tags.append('tag')
 
-    def test_adds_partition(self):
-        image = vmdb.Image()
-        image.add_partition('first', '/dev/foo')
-        self.assertEqual(image.get_tags(), ['first'])
-        self.assertEqual(image.get_dev('first'), '/dev/foo')
-        self.assertEqual(image.get_mount_point('first'), None)
+    def test_sets_dev(self):
+        tags = vmdb.Tags()
+        tags.append('first')
+        tags.set_dev('first', '/dev/foo')
+        self.assertEqual(tags.get_tags(), ['first'])
+        self.assertEqual(tags.get_dev('first'), '/dev/foo')
+        self.assertEqual(tags.get_mount_point('first'), None)
 
     def test_adds_mount_point(self):
-        image = vmdb.Image()
-        image.add_partition('first', '/dev/foo')
-        image.add_mount_point('first', '/mnt/foo')
-        self.assertEqual(image.get_tags(), ['first'])
-        self.assertEqual(image.get_dev('first'), '/dev/foo')
-        self.assertEqual(image.get_mount_point('first'), '/mnt/foo')
-
-    def test_add_mount_point_raises_error_for_unknown_tag(self):
-        image = vmdb.Image()
+        tags = vmdb.Tags()
+        tags.append('first')
+        tags.set_mount_point('first', '/mnt/foo')
+        self.assertEqual(tags.get_tags(), ['first'])
+        self.assertEqual(tags.get_dev('first'), None)
+        self.assertEqual(tags.get_mount_point('first'), '/mnt/foo')
+
+    def test_set_dev_raises_error_for_unknown_tag(self):
+        tags = vmdb.Tags()
         with self.assertRaises(vmdb.UnknownTag):
-            image.add_mount_point('first', '/mnt/foo')
+            tags.set_dev('first', '/mnt/foo')
 
-    def test_add_mount_point_raises_error_for_double_mount(self):
-        image = vmdb.Image()
-        image.add_partition('first', '/dev/foo')
-        image.add_mount_point('first', '/mnt/foo')
+    def test_set_mount_point_raises_error_for_unknown_tag(self):
+        tags = vmdb.Tags()
+        with self.assertRaises(vmdb.UnknownTag):
+            tags.set_mount_point('first', '/mnt/foo')
+
+    def test_set_mount_point_raises_error_for_double_mount(self):
+        tags = vmdb.Tags()
+        tags.append('first')
+        tags.set_mount_point('first', '/mnt/foo')
         with self.assertRaises(vmdb.AlreadyMounted):
-            image.add_mount_point('first', '/mnt/foo')
+            tags.set_mount_point('first', '/mnt/foo')
+
+    def test_set_dev_raises_error_for_double_dev(self):
+        tags = vmdb.Tags()
+        tags.append('first')
+        tags.set_dev('first', '/dev/foo')
+        with self.assertRaises(vmdb.AlreadyHasDev):
+            tags.set_dev('first', '/dev/foo')