Merge lp:~julian-edwards/maas/report-subarches-in-bootimage into lp:maas

Proposed by Julian Edwards
Status: Merged
Approved by: Julian Edwards
Approved revision: 2340
Merged at revision: 2340
Proposed branch: lp:~julian-edwards/maas/report-subarches-in-bootimage
Merge into: lp:maas
Diff against target: 424 lines (+275/-9)
5 files modified
src/provisioningserver/boot/tests/test_tftppath.py (+154/-1)
src/provisioningserver/boot/tftppath.py (+71/-8)
src/provisioningserver/import_images/boot_image_mapping.py (+27/-0)
src/provisioningserver/import_images/testing/factory.py (+9/-0)
src/provisioningserver/import_images/tests/test_boot_image_mapping.py (+14/-0)
To merge this branch: bzr merge lp:~julian-edwards/maas/report-subarches-in-bootimage
Reviewer Review Type Date Requested Status
Jeroen T. Vermeulen (community) Approve
Review via email: mp+219987@code.launchpad.net

Commit message

Make list_boot_images(), which is called from the periodic Celery task, report the supported_subarches which exists in the maas.meta file as subarches in the resource data for each image. This will enable subarch fallback to the right image when looking for a boot image.

Description of the change

I am throwing this up before I've tested it on my rig so I can get some early feedback. There's probably a fair bit that needs tidying up but given I don't overlap with you lot at the moment, please forgive my indulgence :)

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Revision history for this message
Jeroen T. Vermeulen (jtv) wrote :

Comments inline. Several things need, or may need, addressing before this can land, including the docstrings.

review: Approve
Revision history for this message
Julian Edwards (julian-edwards) wrote :
Download full text (6.8 KiB)

On 20/05/14 02:49, Jeroen T. Vermeulen wrote:
> Review: Approve
>
> Comments inline. Several things need, or may need, addressing before this can land, including the docstrings.

Thanks for reviewing.

I would have liked to have split this into smaller branches for better
focused changed, but a) it evolved over time, and b) I'd be blocked on
reviews that I won't get until my night-time. So, sorry for the
larger-than-I-wanted branch. Move back to BKK and they get smaller :)

> Don't forget to run "make format" when you're done

Done!

>> +
>> + def test_extract_metadata(self):
>> + resource = dict(
>> + subarches=factory.make_name("subarch"),
>> + other_item=factory.make_name("other"),
>
> Shouldn't that be a list of subarches, i.e. [factory.make_name("subarch")] (with the added brackets)?

No, there is only one "subarches" per resource, it's just a string.

>> + def _make_path(self):
>> + osystem = factory.make_name("os")
>
> The underscore doesn't do much for us in a test case... If I were you I'd just leave it out as unnecessary reading.

I honestly disagree here. I don't know if this is an unwritten rule or
not, but things starting with underscore tell me that they are exclusive
to this class (or at least *should be*). Without it, I would wonder if
make_path came from the test case base class, especially given its
factory-like nature.

>> + params = extract_image_params(path, "")
>> +
>> + self.assertEqual(
>> + [
>
> Is ordering explicitly guaranteed? If not, best just use assertItemsEqual.

Ah, good spot!

>> -def extract_image_params(path):
>> +def extract_metadata(metadata, params):
>> + """Examine the maas.meta file for any required metadata.
>> +
>> + :param metadata: contents of the maas.meta file
>> + :param params: A dict of path components for the image
>> + (see extract_image_params).
>
> I am confused. This talks about a dict of path components; the documentation for extract_image_params talks about a list of boot-image dicts; and the :return: documentation for extract_image_params talks about a dict of metadata. How do these things fit together?

I was referring to the return value of extract_image_params, but as it
confused you I've removed the reference entirely and directly explained
in the docstring what is required.

>> +def extract_image_params(path, maas_meta):
>> """Represent a list of TFTP path elements as a list of boot-image dicts.
>>
>> - The path must consist of a full [osystem, architecture, subarchitecture,
>> - release] that identify a kind of boot that we may need an image for.
>> + :param path: Must consist of a full [osystem, architecture,
>> + subarchitecture, release] that identify a kind of boot for which we
>
> No need to say "Must consist of" any more.

I'm not sure what you are driving at, but I've re-worded it anyway.

>
>> + may need an image.
>> + :param maas_meta: Contents of the maas.meta file. This may be an
>> + empty string.
>> +
>> + :return: A dict, which may also include additional items of meta-data
>> + that are not elements in the path, such...

Read more...

Revision history for this message
Julian Edwards (julian-edwards) wrote :

This tested out on my rig, so landing it. There is one more problem to fix in a subsequent branch: the pxeconfig has the path to the node's subarch instead of the image's.

Revision history for this message
MAAS Lander (maas-lander) wrote :
Download full text (16.2 KiB)

The attempt to merge lp:~julian-edwards/maas/report-subarches-in-bootimage into lp:maas failed. Below is the output from the failed tests.

Ign http://security.ubuntu.com trusty-security InRelease
Get:1 http://security.ubuntu.com trusty-security Release.gpg [933 B]
Get:2 http://security.ubuntu.com trusty-security Release [58.5 kB]
Ign http://nova.clouds.archive.ubuntu.com trusty InRelease
Ign http://nova.clouds.archive.ubuntu.com trusty-updates InRelease
Hit http://nova.clouds.archive.ubuntu.com trusty Release.gpg
Get:3 http://nova.clouds.archive.ubuntu.com trusty-updates Release.gpg [933 B]
Hit http://nova.clouds.archive.ubuntu.com trusty Release
Get:4 http://nova.clouds.archive.ubuntu.com trusty-updates Release [58.5 kB]
Get:5 http://security.ubuntu.com trusty-security/main Sources [14.7 kB]
Hit http://nova.clouds.archive.ubuntu.com trusty/main Sources
Get:6 http://security.ubuntu.com trusty-security/universe Sources [4,212 B]
Hit http://nova.clouds.archive.ubuntu.com trusty/universe Sources
Get:7 http://security.ubuntu.com trusty-security/main amd64 Packages [47.0 kB]
Hit http://nova.clouds.archive.ubuntu.com trusty/main amd64 Packages
Hit http://nova.clouds.archive.ubuntu.com trusty/universe amd64 Packages
Hit http://nova.clouds.archive.ubuntu.com trusty/main Translation-en
Get:8 http://security.ubuntu.com trusty-security/universe amd64 Packages [17.7 kB]
Hit http://nova.clouds.archive.ubuntu.com trusty/universe Translation-en
Hit http://security.ubuntu.com trusty-security/main Translation-en
Hit http://security.ubuntu.com trusty-security/universe Translation-en
Ign http://security.ubuntu.com trusty-security/main Translation-en_US
Ign http://security.ubuntu.com trusty-security/universe Translation-en_US
Ign http://nova.clouds.archive.ubuntu.com trusty/main Translation-en_US
Ign http://nova.clouds.archive.ubuntu.com trusty/universe Translation-en_US
Get:9 http://nova.clouds.archive.ubuntu.com trusty-updates/main Sources [35.9 kB]
Get:10 http://nova.clouds.archive.ubuntu.com trusty-updates/universe Sources [23.8 kB]
Get:11 http://nova.clouds.archive.ubuntu.com trusty-updates/main amd64 Packages [83.4 kB]
Get:12 http://nova.clouds.archive.ubuntu.com trusty-updates/universe amd64 Packages [64.3 kB]
Hit http://nova.clouds.archive.ubuntu.com trusty-updates/main Translation-en
Hit http://nova.clouds.archive.ubuntu.com trusty-updates/universe Translation-en
Ign http://nova.clouds.archive.ubuntu.com trusty-updates/main Translation-en_US
Ign http://nova.clouds.archive.ubuntu.com trusty-updates/universe Translation-en_US
Fetched 410 kB in 0s (1,347 kB/s)
Reading package lists...
sudo DEBIAN_FRONTEND=noninteractive apt-get -y \
     --no-install-recommends install apache2 bind9 bind9utils build-essential bzr-builddeb curl daemontools debhelper dh-apport distro-info dnsutils firefox freeipmi-tools ipython isc-dhcp-common libjs-raphael libjs-yui3-full libjs-yui3-min libpq-dev make postgresql python-amqplib python-bzrlib python-celery python-convoy python-crochet python-cssselect python-curtin python-dev python-distro-info python-django python-django-piston python-django-south python-djorm-ext-pgarray python-docutils python-formencode python-httplib2 py...

Revision history for this message
Jeroen T. Vermeulen (jtv) wrote :

Yes, I would feel better with the line breaks and a mention of NOQA, thanks.

Revision history for this message
Julian Edwards (julian-edwards) wrote :

On 20/05/14 18:09, Jeroen T. Vermeulen wrote:
> Yes, I would feel better with the line breaks and a mention of NOQA, thanks.
>

Ok I'll do that in a followup branch.

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1=== modified file 'src/provisioningserver/boot/tests/test_tftppath.py'
2--- src/provisioningserver/boot/tests/test_tftppath.py 2014-05-02 15:13:14 +0000
3+++ src/provisioningserver/boot/tests/test_tftppath.py 2014-05-20 00:47:19 +0000
4@@ -25,6 +25,8 @@
5 compose_image_path,
6 drill_down,
7 extend_path,
8+ extract_image_params,
9+ extract_metadata,
10 is_visible_subdir,
11 list_boot_images,
12 list_subdirs,
13@@ -34,6 +36,14 @@
14 OperatingSystem,
15 OperatingSystemRegistry,
16 )
17+from provisioningserver.import_images.boot_image_mapping import (
18+ BootImageMapping,
19+ )
20+from provisioningserver.import_images.helpers import ImageSpec
21+from provisioningserver.import_images.testing.factory import (
22+ make_image_spec,
23+ set_resource,
24+ )
25 from provisioningserver.testing.boot_images import (
26 make_boot_image_storage_params,
27 )
28@@ -79,13 +89,15 @@
29 ]
30
31
32-def make_image(params, purpose):
33+def make_image(params, purpose, metadata=None):
34 """Describe an image as a dict similar to what `list_boot_images` returns.
35
36 The `params` are as returned from `make_boot_image_storage_params`.
37 """
38 image = params.copy()
39 image['purpose'] = purpose
40+ if metadata is not None:
41+ image.update(metadata)
42 return image
43
44
45@@ -133,6 +145,17 @@
46 factory.make_file(image_dir, 'linux')
47 factory.make_file(image_dir, 'initrd.gz')
48
49+ def make_meta_file(self, image_params, image_resource, tftproot):
50+ image = ImageSpec(
51+ arch=image_params["architecture"],
52+ subarch=image_params["subarchitecture"],
53+ release=image_params["release"], label=image_params["label"])
54+ mapping = BootImageMapping()
55+ mapping.setdefault(image, image_resource)
56+ maas_meta = mapping.dump_json()
57+ with open(os.path.join(tftproot, "maas.meta"), "wb") as f:
58+ f.write(maas_meta)
59+
60 def test_compose_image_path_follows_storage_directory_layout(self):
61 osystem = factory.make_name('osystem')
62 arch = factory.make_name('arch')
63@@ -203,6 +226,21 @@
64 ],
65 list_boot_images(self.tftproot))
66
67+ def test_list_boot_images_merges_maas_meta_data(self):
68+ params = make_boot_image_storage_params()
69+ self.make_image_dir(params, self.tftproot)
70+ # The required metadata is called "subarches" in maas.meta
71+ metadata = dict(subarches=factory.make_name("subarches"))
72+ self.make_meta_file(params, metadata, self.tftproot)
73+ purposes = ['install', 'commissioning', 'xinstall']
74+ make_osystem(self, params['osystem'], purposes)
75+ # The API requires "supported_subarches".
76+ expected_metadata = dict(supported_subarches=metadata["subarches"])
77+ self.assertItemsEqual(
78+ [make_image(params, purpose, expected_metadata)
79+ for purpose in purposes],
80+ list_boot_images(self.tftproot))
81+
82 def test_list_boot_images_empty_on_missing_osystems(self):
83 params = [make_boot_image_storage_params() for counter in range(3)]
84 for param in params:
85@@ -296,3 +334,118 @@
86 self.assertEqual(
87 [[deep_dir, subdir]],
88 drill_down(base_dir, [[shallow_dir], [deep_dir]]))
89+
90+ def test_extract_metadata(self):
91+ resource = dict(
92+ subarches=factory.make_name("subarch"),
93+ other_item=factory.make_name("other"),
94+ )
95+ image = make_image_spec()
96+ mapping = set_resource(image_spec=image, resource=resource)
97+ metadata = mapping.dump_json()
98+
99+ # Lack of consistency across maas in naming arch vs architecture
100+ # and subarch vs subarchitecture means I can't just do a simple
101+ # dict parameter expansion here.
102+ params = {
103+ "architecture": image.arch,
104+ "subarchitecture": image.subarch,
105+ "release": image.release,
106+ "label": image.label,
107+ }
108+ extracted_data = extract_metadata(metadata, params)
109+
110+ # We only expect the supported_subarches key from the resource data.
111+ expected = dict(supported_subarches=resource["subarches"])
112+ self.assertEqual(expected, extracted_data)
113+
114+ def _make_path(self):
115+ osystem = factory.make_name("os")
116+ arch = factory.make_name("arch")
117+ subarch = factory.make_name("subarch")
118+ release = factory.make_name("release")
119+ label = factory.make_name("label")
120+ path = (osystem, arch, subarch, release, label)
121+ return path, osystem, arch, subarch, release, label
122+
123+ def _patch_osystem_registry(self, values):
124+ get_item = self.patch(OperatingSystemRegistry, "get_item")
125+ item_mock = Mock()
126+ item_mock.get_boot_image_purposes.return_value = values
127+ get_item.return_value = item_mock
128+
129+ def test_extract_image_params_with_no_metadata(self):
130+ path, osystem, arch, subarch, release, label = self._make_path()
131+
132+ # Patch OperatingSystemRegistry to return a fixed list of
133+ # values.
134+ purpose1 = factory.make_name("purpose")
135+ purpose2 = factory.make_name("purpose")
136+ purposes = [purpose1, purpose2]
137+ self._patch_osystem_registry(purposes)
138+
139+ params = extract_image_params(path, "")
140+
141+ self.assertItemsEqual(
142+ [
143+ {
144+ "osystem": osystem,
145+ "architecture": arch,
146+ "subarchitecture": subarch,
147+ "release": release,
148+ "label": label,
149+ "purpose": purpose1,
150+ },
151+ {
152+ "osystem": osystem,
153+ "architecture": arch,
154+ "subarchitecture": subarch,
155+ "release": release,
156+ "label": label,
157+ "purpose": purpose2,
158+ },
159+ ],
160+ params)
161+
162+ def test_extract_image_params_with_metadata(self):
163+ path, osystem, arch, subarch, release, label = self._make_path()
164+
165+ # Patch OperatingSystemRegistry to return a fixed list of
166+ # values.
167+ purpose1 = factory.make_name("purpose")
168+ purpose2 = factory.make_name("purpose")
169+ purposes = [purpose1, purpose2]
170+ self._patch_osystem_registry(purposes)
171+
172+ # Create some maas.meta content.
173+ image = ImageSpec(
174+ arch=arch, subarch=subarch, release=release, label=label)
175+ image_resource = dict(subarches=factory.make_name("subarches"))
176+ mapping = BootImageMapping()
177+ mapping.setdefault(image, image_resource)
178+ maas_meta = mapping.dump_json()
179+
180+ params = extract_image_params(path, maas_meta)
181+
182+ self.assertItemsEqual(
183+ [
184+ {
185+ "osystem": osystem,
186+ "architecture": arch,
187+ "subarchitecture": subarch,
188+ "release": release,
189+ "label": label,
190+ "purpose": purpose1,
191+ "supported_subarches": image_resource["subarches"],
192+ },
193+ {
194+ "osystem": osystem,
195+ "architecture": arch,
196+ "subarchitecture": subarch,
197+ "release": release,
198+ "label": label,
199+ "purpose": purpose2,
200+ "supported_subarches": image_resource["subarches"],
201+ },
202+ ],
203+ params)
204
205=== modified file 'src/provisioningserver/boot/tftppath.py'
206--- src/provisioningserver/boot/tftppath.py 2014-05-19 13:16:53 +0000
207+++ src/provisioningserver/boot/tftppath.py 2014-05-20 00:47:19 +0000
208@@ -25,6 +25,10 @@
209 import os.path
210
211 from provisioningserver.driver import OperatingSystemRegistry
212+from provisioningserver.import_images.boot_image_mapping import (
213+ BootImageMapping,
214+ )
215+from provisioningserver.import_images.helpers import ImageSpec
216
217
218 logger = getLogger(__name__)
219@@ -112,11 +116,43 @@
220 extend_path(directory, path) for path in paths))
221
222
223-def extract_image_params(path):
224+def extract_metadata(metadata, params):
225+ """Examine the maas.meta file for any required metadata.
226+
227+ :param metadata: contents of the maas.meta file
228+ :param params: A dict of path components for the image
229+ (architecture, subarchitecture, release and label).
230+ :return: a dict of name/value metadata pairs. Currently, only
231+ "subarches" is extracted.
232+ """
233+ mapping = BootImageMapping.load_json(metadata)
234+
235+ image = ImageSpec(
236+ arch=params["architecture"],
237+ subarch=params["subarchitecture"],
238+ release=params["release"],
239+ label=params["label"],
240+ )
241+ try:
242+ resource = mapping.mapping[image]
243+ except KeyError:
244+ return {}
245+
246+ return dict(supported_subarches=resource["subarches"])
247+
248+
249+def extract_image_params(path, maas_meta):
250 """Represent a list of TFTP path elements as a list of boot-image dicts.
251
252- The path must consist of a full [osystem, architecture, subarchitecture,
253- release] that identify a kind of boot that we may need an image for.
254+ :param path: Tuple or list that consists of a full [osystem, architecture,
255+ subarchitecture, release] that identify a kind of boot for which we
256+ may need an image.
257+ :param maas_meta: Contents of the maas.meta file. This may be an
258+ empty string.
259+
260+ :return: A list of dicts, each of which may also include additional
261+ items of meta-data that are not elements in the path, such as
262+ "subarches".
263 """
264 osystem, arch, subarch, release, label = path
265 osystem_obj = OperatingSystemRegistry.get_item(osystem, default=None)
266@@ -125,13 +161,27 @@
267
268 purposes = osystem_obj.get_boot_image_purposes(
269 arch, subarch, release, label)
270- return [
271+
272+ # Expand the path into a list of dicts, one for each boot purpose.
273+ params = [
274 dict(
275 osystem=osystem, architecture=arch, subarchitecture=subarch,
276 release=release, label=label, purpose=purpose)
277 for purpose in purposes
278 ]
279
280+ # Merge in the meta-data.
281+ for image_dict in params:
282+ metadata = extract_metadata(maas_meta, image_dict)
283+ image_dict.update(metadata)
284+
285+ return params
286+
287+
288+def maas_meta_file_path(tftproot):
289+ """Return a string containing the full path to maas.meta."""
290+ return os.path.join(tftproot, 'maas.meta')
291+
292
293 def list_boot_images(tftproot):
294 """List the available boot images.
295@@ -149,9 +199,9 @@
296 # Directory does not exist, so return empty list.
297 logger.warning("No boot images have been imported yet.")
298 return []
299- else:
300- # Other error. Propagate.
301- raise
302+
303+ # Other error. Propagate.
304+ raise
305
306 # Starting point for iteration: paths that contain only the
307 # top-level subdirectory of tftproot, i.e. the architecture name.
308@@ -163,8 +213,21 @@
309 for level in ['arch', 'subarch', 'release', 'label']:
310 paths = drill_down(tftproot, paths)
311
312+ # Get hold of image meta-data stored in the maas.meta file.
313+ meta_file_path = maas_meta_file_path(tftproot)
314+ try:
315+ with open(meta_file_path, "rb") as f:
316+ metadata = f.read()
317+ except IOError as e:
318+ if e.errno != errno.ENOENT:
319+ # Unexpected error, propagate.
320+ raise
321+ # No meta file (yet), it means no import has run so just skip
322+ # it.
323+ metadata = ""
324+
325 # Each path we find this way should be a boot image.
326 # This gets serialised to JSON, so we really have to return a list, not
327 # just any iterable.
328 return list(chain.from_iterable(
329- extract_image_params(path) for path in paths))
330+ extract_image_params(path, metadata) for path in paths))
331
332=== modified file 'src/provisioningserver/import_images/boot_image_mapping.py'
333--- src/provisioningserver/import_images/boot_image_mapping.py 2014-04-11 02:14:42 +0000
334+++ src/provisioningserver/import_images/boot_image_mapping.py 2014-05-20 00:47:19 +0000
335@@ -63,3 +63,30 @@
336 data[arch][subarch].setdefault(release, {})
337 data[arch][subarch][release][label] = resource
338 return json.dumps(data, sort_keys=True)
339+
340+ @staticmethod
341+ def load_json(json_data):
342+ """Take a JSON representation and deserialize into an object.
343+
344+ :param json_data: string produced by dump_json(), above.
345+ :return: A BootImageMapping
346+
347+ If the json data is invalid, an empty BootImageMapping is returned.
348+ """
349+ mapping = BootImageMapping()
350+ try:
351+ data = json.loads(json_data)
352+ except ValueError:
353+ return mapping
354+
355+ for arch in data:
356+ for subarch in data[arch]:
357+ for release in data[arch][subarch]:
358+ for label in data[arch][subarch][release]:
359+ image = ImageSpec(
360+ arch=arch, subarch=subarch, release=release,
361+ label=label)
362+ resource = data[arch][subarch][release][label]
363+ mapping.setdefault(image, resource)
364+
365+ return mapping
366
367=== modified file 'src/provisioningserver/import_images/testing/factory.py'
368--- src/provisioningserver/import_images/testing/factory.py 2014-04-08 06:53:34 +0000
369+++ src/provisioningserver/import_images/testing/factory.py 2014-05-20 00:47:19 +0000
370@@ -15,9 +15,12 @@
371 __all__ = [
372 'make_boot_resource',
373 'make_image_spec',
374+ 'make_maas_meta',
375 'set_resource',
376 ]
377
378+from textwrap import dedent
379+
380 from maastesting.factory import factory
381 from provisioningserver.import_images.boot_image_mapping import (
382 BootImageMapping,
383@@ -25,6 +28,12 @@
384 from provisioningserver.import_images.helpers import ImageSpec
385
386
387+def make_maas_meta():
388+ """Return fake maas.meta data."""
389+ return dedent("""\
390+ {"amd64": {"generic": {"precise": {"release": {"content_id": "com.ubuntu.maas:v2:download", "path": "precise/amd64/20140410/raring/generic/boot-kernel", "product_name": "com.ubuntu.maas:v2:boot:12.04:amd64:hwe-r", "subarches": "generic,hwe-p,hwe-q,hwe-r", "version_name": "20140410"}}, "trusty": {"release": {"content_id": "com.ubuntu.maas:v2:download", "path": "trusty/amd64/20140416.1/root-image.gz", "product_name": "com.ubuntu.maas:v2:boot:14.04:amd64:hwe-t", "subarches": "generic,hwe-p,hwe-q,hwe-r,hwe-s,hwe-t", "version_name": "20140416.1"}}}, "hwe-s": {"precise": {"release": {"content_id": "com.ubuntu.maas:v2:download", "path": "precise/amd64/20140410/saucy/generic/boot-kernel", "product_name": "com.ubuntu.maas:v2:boot:12.04:amd64:hwe-s", "subarches": "generic,hwe-p,hwe-q,hwe-r,hwe-s", "version_name": "20140410"}}}}}""") # NOQA
391+
392+
393 def make_boot_resource():
394 """Create a fake resource dict."""
395 return {
396
397=== modified file 'src/provisioningserver/import_images/tests/test_boot_image_mapping.py'
398--- src/provisioningserver/import_images/tests/test_boot_image_mapping.py 2014-04-11 02:13:59 +0000
399+++ src/provisioningserver/import_images/tests/test_boot_image_mapping.py 2014-05-20 00:47:19 +0000
400@@ -23,6 +23,7 @@
401 )
402 from provisioningserver.import_images.testing.factory import (
403 make_image_spec,
404+ make_maas_meta,
405 set_resource,
406 )
407
408@@ -104,3 +105,16 @@
409 },
410 },
411 json.loads(image_dict.dump_json()))
412+
413+ def test_load_json_result_matches_dump_of_own_data(self):
414+ # Loading the test data and dumping it again should result in
415+ # identical test data.
416+ test_meta_file_content = make_maas_meta()
417+ mapping = BootImageMapping.load_json(test_meta_file_content)
418+ dumped = mapping.dump_json()
419+ self.assertEqual(test_meta_file_content, dumped)
420+
421+ def test_load_json_returns_empty_mapping_for_invalid_json(self):
422+ bad_json = ""
423+ mapping = BootImageMapping.load_json(bad_json)
424+ self.assertEqual({}, mapping.mapping)