Commit Graph

645 Commits

Author SHA1 Message Date
Simon Charette 0d397e5a5b Revert "Fixed #22397 -- Issues removing M2M field with explicit through model."
This reverts commit 00e3b9a2a9.

It's causing a regression when tested with the proxy_model_inheritance tests.
2014-04-18 01:27:30 -04:00
Andrew Gorcester 00e3b9a2a9 Fixed #22397 -- Issues removing M2M field with explicit through model.
Changed the migration autodetector to remove models last so that FK
and M2M fields will not be left as dangling references. Added a check
in the migration state renderer to error out in the presence of
dangling references instead of leaving them as strings. Fixed a bug
in the sqlite backend to handle the deletion of M2M fields with
"through" models properly (i.e., do nothing successfully).

Thanks to melinath for report, loic for tests and andrewgodwin and
charettes for assistance with architecture.
2014-04-17 12:54:35 -04:00
Motiejus Jakštys 0e45669fa9 Fixed #22460 -- Explicity remove constraints when dropping a related field. 2014-04-16 15:38:31 -04:00
Simon Charette 72d3889db4 Fixed #22350 -- Consistently serialize bytes and text in migrations.
Thanks to @treyhunner and Loïc for their suggestions and review.
2014-04-13 18:22:26 -04:00
Simon Charette 074d3183d9 Fixed #22363 -- Correctly serialize `django.utils.datetime_safe` objects.
Thanks to linovia for the report.
2014-04-03 14:54:16 -04:00
Loic Bistuer 0fd51cf0bd Fixed #22319 -- Fixed migration external dependencies when there are internal dependencies. 2014-03-31 06:50:38 -04:00
Loic Bistuer a449e7feec Fixed #22359 -- Changing M2M field to blank=True failed on sqlite. 2014-03-31 06:13:19 -04:00
Tim Graham 42336c84a0 Fixed #22331 -- Made MigrationAutodetector ignore unmanaged models.
This commit reverts 69d4b1c and tackle the issue from a different angle.
Models remain present in the project state, but are now ignored by the
autodetector.
2014-03-25 18:30:58 -04:00
Loic Bistuer 69d4b1c3ea Fixed #22331 -- Fixed migrations ProjectState to ignore unmanaged models. 2014-03-25 10:33:44 -04:00
Stephen Burrows 35ed792cf2 Fixed #22300 -- Fixed crash in migrations when changing non-relational field to relational. 2014-03-25 07:46:15 -04:00
Andrew Godwin 81f5408c7a Fixed #22275: unique_together broken if ForeignKey split into new file.
Thanks to bak1an for the patch.
2014-03-19 21:23:21 -07:00
Andrew Godwin f4d91638fc Remove failing test while we fix the underlying bug 2014-03-11 10:33:57 -07:00
Chris Beaven 107c9f5453 Fix AlterField migrations that are related to a RenameModel migration 2014-03-11 17:13:26 +13:00
Chris Beaven 40f6ca54f8 Fix autodetector creation of RenameModel migration to capitalize model names 2014-03-11 12:23:45 +13:00
Chris Beaven 7feb70eef3 Fixed #22239 -- Add auto detection of renamed models 2014-03-10 13:55:44 +13:00
Andrew Godwin abccbcf52d Fixed #21843: Remove explicit ID column setting in test 2014-03-08 16:04:21 -08:00
Andrew Godwin cdf6eba181 Merge pull request #2315 from bendavis78/issues/22073
Fixed #22073 - Ensure CreateTable operation handles backwards migration correctly when M2M fields are present
2014-03-08 15:44:45 -08:00
Andrew Godwin e46e15e5a1 Fixed #22204: Bad circular-dep-breaking if more than one per run 2014-03-06 13:22:42 -08:00
Alex Gaynor a248c88372 Fixed three small flake8 violations. 2014-03-04 15:13:15 -08:00
Loic Bistuer 6436f1fad9 Fixed #21893 -- ModelState didn't account for MTI parents inherited from abstract models. 2014-03-05 03:25:14 +07:00
Loic Bistuer 99291f5db0 Added tests for MTI in RunPython. 2014-03-05 03:17:52 +07:00
Anubhav Joshi bb2ca9fe6c Fixed #22172 -- Allowed index_together to be a single list (rather than list of lists)..
Thanks EmilStenstrom for the suggestion.
2014-03-01 15:44:42 -05:00
Baptiste Mispelon c679cb7f60 Fixed #22168 -- Fixed migrations failing on sqlite when column names are SQL keywords
Thanks to trac user fallen_flint for the report and initial patch.
2014-03-01 13:45:45 +01:00
Alex Gaynor a8a5c31966 Two whitespace changes to appease flake8 2014-02-23 11:07:52 -06:00
Andrew Gorcester 202bf69c2f Fixed #22095 -- Enabled backward migrations for RunPython operations
Added reversible property to RunPython so that migrations will not
refuse to reverse migrations including RunPython operations, so long as
reverse_code is set in the RunPython constructor. Included tests to
check the reversible property on RunPython and the similar RunSQL.
2014-02-23 09:30:02 +01:00
Ben Davis df2652c448 Fixed #22073 - Ensure CreateTable operation handles backwards migration correctly when M2M fields are present 2014-02-17 16:51:40 -06:00
Andrew Godwin 3c547a423f Merge pull request #2270 from bmispelon/ticket-22030
Fixed #22030 -- Don't assume that all fields have a swappable_setting at...
2014-02-17 01:16:49 +00:00
Anton Baklanov 0bd92d68ad Fixed #22035 -- reordered migration operations
Now AddField actions appear in operations list before AlterUniqueTogether
actions.

Thanks to SmileyChris for the report.
2014-02-14 20:00:39 -05:00
Baptiste Mispelon 6873eeeefb Fixed #22030 -- Don't assume that all fields have a swappable_setting attribute. 2014-02-13 17:43:21 +01:00
Baptiste Mispelon c3434fed5b Removed test for migration check forgotten in 7e941ba67c. 2014-02-13 09:31:39 +01:00
Andrew Godwin bad9456b9c Fix my slightly hasty autodetector changes 2014-02-12 17:22:50 +00:00
Andrew Godwin 97a8fd4682 Fixed #21954: Raise nice error when serializing datetimes with timezones 2014-02-09 11:17:38 +00:00
Tim Graham 4f8e8a6ec2 Removed unused imports + other flake8 fixes. 2014-02-09 06:13:10 -05:00
Andrew Godwin 98dd8dd02e Fixed #21892: RunPython no longer accepts strings 2014-02-09 10:54:02 +00:00
mlavin a3e0d7753d Adding tests for check_migrations. 2014-02-08 09:05:27 -05:00
Michael Manfre ad913f242d Fix regress added to migrations.test_operations.test_alter_field_pk_fk 2014-02-02 15:44:01 -05:00
Michael Manfre 3ffeb93186 Ensure cursors are closed when no longer needed.
This commit touchs various parts of the code base and test framework. Any
found usage of opening a cursor for the sake of initializing a connection
has been replaced with 'ensure_connection()'.
2014-02-02 12:47:21 -05:00
Alex Gaynor 2ba09c000d Added some missing whitespace around arithmetic operators 2014-01-22 09:21:05 -06:00
Markus Holtermann 047394f79c Fixed #21852 -- Make migration writer serialize iterators 2014-01-22 09:21:54 +01:00
Alex Gaynor be8173af51 Fixed a small collection of flake8 violations that had snuck in 2014-01-19 21:15:31 -06:00
Russell Keith-Magee d818e0c9b2 Fixed #16905 -- Added extensible checks (nee validation) framework
This is the result of Christopher Medrela's 2013 Summer of Code project.

Thanks also to Preston Holmes, Tim Graham, Anssi Kääriäinen, Florian
Apolloner, and Alex Gaynor for review notes along the way.

Also: Fixes #8579, fixes #3055, fixes #19844.
2014-01-20 10:45:21 +08:00
Andrew Godwin 51832c8aec Remove other unicode literal 2014-01-19 18:57:59 +00:00
Andrew Godwin b1fc8c19b2 Remove unicode prefix that snuck in 2014-01-19 18:57:06 +00:00
Andrew Godwin 3f1a008266 Fixed #21664: Multi-table inheritance was duplicating _ptr fields 2014-01-19 18:35:49 +00:00
Andrew Godwin af4a8478e4 Fixed #21783: (again) Found second source of bug, also squashed it. 2014-01-19 17:43:31 +00:00
Loic Bistuer 374faa4721 Fixed #21323 -- Improved readability of serialized Operation. 2014-01-20 00:16:07 +07:00
Andrew Godwin c9de1b4a55 Implement swappable model support for migrations 2014-01-19 16:43:12 +00:00
Andrew Godwin 9ae17d994b Make test stronger to hopefully fix odd Jenkins failure 2014-01-08 21:20:29 +00:00
Andrew Godwin 64887c644a Fixed #21142: Dependency failures on unmigrated apps. 2014-01-08 13:00:12 +00:00
Aymeric Augustin 7ed20e0153 Populated Apps instances immediately by default. 2013-12-30 22:11:17 +01:00
Aymeric Augustin 38ce41103f Used Apps.clear_cache() in tests that alter the app registry. 2013-12-29 21:25:28 +01:00
Aymeric Augustin 1716b7ce5a Renamed AppCache to Apps.
Also renamed app_cache to apps and "app cache" to "app registry".

Deprecated AppCache.app_cache_ready() in favor of Apps.ready().
2013-12-24 12:25:17 +01:00
Aymeric Augustin 82a35e24d4 Replaced ad-hoc caching of get_models with lru_cache.
Invalidate properly the cache whenever all_models or app_configs change.
This fixes some isolation issues in the test suite.
2013-12-24 10:56:50 +01:00
Aymeric Augustin e32095616c Imported override_settings from its new location. 2013-12-23 21:37:56 +01:00
Aymeric Augustin da16bb30ff Dropped AppCache._empty, _with_app and _without_app.
It's now easier to achieve the same effect with modify_settings or
override_settings.
2013-12-23 21:37:56 +01:00
Aymeric Augustin 2fef9e5375 Moved apps back in the toplevel django namespace.
Reverted 4a56a93cc4.
2013-12-22 11:39:55 +01:00
Aymeric Augustin 2239081ff1 Expurged INSTALLED_APPS from code and tests.
Except the app cache code and a few specific tests, of course.
2013-12-22 11:39:18 +01:00
Aymeric Augustin f25fa9d859 Deprecated load_app().
Adjusted several tests that used it to add apps to the app cache and
then attempted to remove them by manipulating attributes directly.

Also renamed invalid_models to invalid_models_tests to avoid clashing
application labels between the outer and the inner invalid_models
applications.
2013-12-22 11:39:17 +01:00
Aymeric Augustin 742ed9878e Refactored registration of models.
Got rid of AppConfig._stub. As a side effect, app_cache.app_configs now
only contains entries for applications that are in INSTALLED_APPS, which
is a good thing and will allow dramatic simplifications (which I will
perform in the next commit). That required adjusting all methods that
iterate on app_configs without checking the "installed" flag, hence the
large changes in get_model[s].

Introduced AppCache.all_models to store models:
- while the app cache is being populated and a suitable app config
  object to register models isn't available yet;
- for applications that aren't in INSTALLED_APPS since they don't have
  an app config any longer.

Replaced get_model(seed_cache=False) by registered_model() which can be
kept simple and safe to call at any time, and removed the seed_cache
argument to get_model[s]. There's no replacement for that private API.

Allowed non-master app caches to go through populate() as it is now
safe to do so. They were introduced in 1.7 so backwards compatibility
isn't a concern as long as the migrations framework keeps working.
2013-12-22 11:39:17 +01:00
Aymeric Augustin 0242c56fd8 Deborgified the app cache.
Improved Andrew's hack to create temporary app caches to handle
migrations. Now the main app cache has a "master" flag set to True
(which is a non-default keyword argument, thus unlikely to be used by
mistake). Other app cache instances have "master" set to False.

The only sanctioned way to access the app cache is by importing
django.core.apps.app_cache.

If you were instanciating an app cache and relying on the Borg pattern,
you'll have to refactor your code.
2013-12-17 21:53:18 +01:00
Aymeric Augustin 6e895f9e06 Removed superfluous models.py files.
Added comments in the three empty models.py files that are still needed.

Adjusted the test runner to add applications corresponding to test
labels to INSTALLED_APPS even when they don't have a models module.
2013-12-17 11:16:48 +01:00
Aymeric Augustin 4a56a93cc4 Moved the new app cache inside core. 2013-12-17 10:17:46 +01:00
Aymeric Augustin ebda5800ae Simplified register_models.
Since it's never called with more than one model at a time the current
signature is needlessly complicated.
2013-12-17 10:17:45 +01:00
Aymeric Augustin b55282b98b Moved list of models inside AppConfig instances.
This commit is a refactoring with no change of functionality, according
to the following invariants:

- An app_label that was in app_configs and app_models stays in
  app_config and has its 'installed' attribute set to True.

- An app_label that was in app_models but not in app_configs is added to
  app_configs and has its 'installed' attribute set to True.

As a consequence, all the code that iterated on app_configs is modified
to check for the 'installed' attribute. Code that iterated on app_models
is rewritten in terms of app_configs.

Many tests that stored and restored the state of the app cache were
updated.

In the long term, we should reconsider the usefulness of allowing
importing models from non-installed applications. This doesn't sound
particularly useful, can be a trap in some circumstances, and causes
significant complexity in sensitive areas of Django.
2013-12-17 10:17:44 +01:00
Aymeric Augustin 8662654d6d Removed module-level functions for the app cache.
Since the original ones in django.db.models.loading were kept only for
backwards compatibility, there's no need to recreate them. However, many
internals of Django still relied on them.

They were also imported in django.db.models. They never appear in the
documentation, except a quick mention of get_models and get_app in the
1.2 release notes to document an edge case in GIS. I don't think that
makes them a public API.

This commit doesn't change the overall amount of global state but
clarifies that it's tied to the app_cache object instead of hiding it
behind half a dozen functions.
2013-12-17 10:17:44 +01:00
Aymeric Augustin 9217b89da3 Removed BaseAppCache.app_store.
It was only storing redundant information. This is part of the effort to
allow applications without a models module.
2013-12-17 10:17:44 +01:00
Aymeric Augustin 860c2c8bc5 Moved django.db.models.loading to django.apps.cache.
This commit doesn't contain any code changes; it's purely a refactoring.
2013-12-17 10:17:43 +01:00
Andrew Godwin 5db028affb Fix altering of SERIAL columns and InnoDB being picky about FK changes 2013-12-11 14:19:05 +00:00
Baptiste Mispelon 19e4374971 Fixed ModelState breaking when unique_together has unhashable elements. 2013-12-06 15:22:52 +01:00
Baptiste Mispelon aba75b0d71 Fixed TypeError when rendering ModelState with multiple bases. 2013-12-06 00:55:31 +01:00
Alex Gaynor cbf8e8aa12 Fixed a flake8 error 2013-12-05 08:08:34 -06:00
Andrew Godwin 3b8e46cbc7 Migration VCS conflict detection and --merge for makemigrations 2013-12-04 16:01:49 +00:00
Andrew Godwin ce05b8a69e Don't make a second migration if there was a force-null-default addcol. 2013-12-04 13:56:22 +00:00
Andrew Godwin 5e63977c0e Fixed #21438: makemigrations now detects ManyToManyFields 2013-11-27 15:28:33 +00:00
Alex Gaynor e5b7045422 flake8 fixes 2013-11-06 20:00:48 -08:00
Andrew Godwin 106b019dc9 Massive migration optimiser improvements + RenameModel opn 2013-11-06 13:47:58 +00:00
Alex Gaynor f67e18f39e Fixed all E251 violations 2013-11-03 10:17:58 -08:00
Tim Graham 36ded01527 Fixed #21302 -- Fixed unused imports and import *. 2013-11-02 15:24:56 -04:00
Alex Gaynor 8faaf03b86 Fixed some flake8 issues 2013-10-30 10:42:35 -07:00
Andrew Godwin e9cb333bc3 Auto-apply initial migrations if their tables exist already. 2013-10-30 15:17:49 +00:00
Ramiro Morales 88f03db05f Fixed test that reads a migration file from disk.
We need to make sure content read from the file is decoded from UTF-8
right from the start so Python doesn't try to use another encoding
(read: ASCII/CP1252 under Windows.)
2013-10-27 14:54:56 -03:00
Andrew Godwin 5ab8b5d72c Fix migration planner to fully understand squashed migrations. And test. 2013-10-23 22:56:54 +01:00
Alasdair Nicol c3aa2948c6 Fixed #21298 -- Fixed E301 pep8 warnings 2013-10-23 13:45:03 +01:00
Loic Bistuer e565e1332d Fixed #21275 -- Fixed a serializer error when generating migrations for contrib.auth.
The migration serializer now looks for a deconstruct method on any object.
2013-10-21 14:54:52 -04:00
Loic Bistuer 8d6953d55c Added support for serializing class methods. - Refs #21290.
The new handling allows us to do away with the whitelisting that was
required to support date and datetime objects.
2013-10-19 12:10:18 -04:00
Loic Bistuer 584110417f Fixed #21283 -- Added support for migrations if models is a package.
Thanks Markus Holtermann for the report.
2013-10-19 09:48:57 -04:00
Loic Bistuer 5008706345 Added test for a921f06 - refs #21280.
This commit also lays the groundwork for future tests for the
makemigrations command.
2013-10-17 12:08:17 -04:00
Andrew Godwin 42f8666f6a Improve migration optimizer to be able to optimize through other ops 2013-10-16 11:09:33 +01:00
Tim Graham 1dae4ac177 Whitespace cleanup.
* Removed trailing whitespace.
* Added newline to EOF if missing.
* Removed blank lines at EOF.
* Removed some stray tabs.
2013-10-10 16:49:20 -04:00
Javed Khan 4dbd95ad65 Fixed #21236 -- Allowed migrations to work with unique_together tuples.
Thanks hjwp for the report.
2013-10-07 09:39:14 -04:00
Andrew Godwin a80d9ab0fe Initial version of MigrationOptimizer and tests 2013-10-02 17:34:22 +01:00
Andrew Godwin f671fb9d11 Remove most errors when running migration tests twice 2013-09-25 16:11:05 +01:00
Andrew Godwin fe9f342d8c Allow callables as the argument to RunPython 2013-09-25 16:10:43 +01:00
Andrew Godwin 3b810c5656 Add RunPython migration operation and tests 2013-09-25 13:58:07 +01:00
Andrew Godwin 05656f2388 Add equality support for Project/ModelState 2013-09-25 13:47:46 +01:00
Markus Holtermann a772ea8117 Fixed #21115 -- Fixed NameError in migrate --list command 2013-09-17 12:53:59 -04:00
Markus Holtermann 5a424c2393 Fixed #21114 -- Migrations must not have a dependency to themselves. 2013-09-17 11:47:19 -04:00
Loic Bistuer d59f1993f1 Made MigrationWriter look for a "deconstruct" attribute on functions.
Refs #20978.
2013-09-10 10:12:23 -04:00
Andrew Godwin bacbbb481d RunSQL migration operation and alpha SeparateDatabaseAndState op'n. 2013-09-07 11:03:38 -05:00
Loic Bistuer adc0ab3386 Fixed #21037 -- Made MigrationWriter raise a ValueError when serializing lambda functions. 2013-09-06 20:13:01 -04:00
Andrew Godwin efd1e6096e Adding 'sqlmigrate' command and quote_parameter to support it. 2013-09-06 15:28:12 -05:00
Andrew Godwin 05e14e8eaf Migration autodetector now corerctly deals with proxy models 2013-09-06 12:39:46 -05:00
Andrew Godwin be983ee403 Also test failure case of ProjectState dependency resolution 2013-09-06 12:18:24 -05:00
Andrew Godwin cdeff3acc2 Project/ModelState now correctly serialize multi-model inheritance 2013-09-06 12:16:03 -05:00
Markus Holtermann bd8e1a354c Fixed #20977 -- Fixed writing migrations to disk on Python 3 2013-09-06 09:51:58 -04:00
Loic Bistuer e1266e50b2 Fixed #21015 -- Fixed MigrationLoader when importlib.import_module returns a file module or an empty directory. 2013-09-06 08:30:19 -04:00
Loic Bistuer 82bbb9fe81 Fixed #21014 -- Fixed gobbled ImportError in MigrationLoader. 2013-09-06 08:30:18 -04:00
Loic Bistuer 34d52fd32e Fixed #21010 -- Changed ModelState to only copy _meta.local_fields. 2013-09-04 14:05:59 -04:00
Loic Bistuer ff9e116198 Fixed #21008 -- Made MigrationWriter handle Promise objects. 2013-08-31 20:26:44 -04:00
Alex Gaynor 8363406dad Removed usage of u"" string prefix, which doesn't work on python3.2 2013-08-23 04:56:37 -07:00
Andrew Godwin ac45f9c9c5 Fix some small errors in the tests 2013-08-23 12:07:43 +01:00
Andrew Godwin 2e7f45a372 Change autodetector changes API to be just one method 2013-08-21 22:25:15 +01:00
Andrew Godwin 52edc16086 Add more stringent M2M tests and fix the bug they exposed 2013-08-19 13:50:26 +01:00
Andrew Godwin b61b634628 Fix weird planning issues when already fully migrated. 2013-08-11 15:28:51 +01:00
Andrew Godwin fddc5957c5 Implement allow_migrate for migration operations 2013-07-30 12:34:31 +01:00
Andrew Godwin a758c9c186 Add test for creating M2Ms 2013-07-25 16:36:58 +01:00
Andrew Godwin 00276e0414 Add tests for the migrate command and fix a bug they exposed 2013-07-25 13:52:35 +01:00
Andrew Godwin 162f7b938f Make migrate command recognise prefixes and 'zero'. 2013-07-22 19:43:58 +01:00
Andrew Godwin 61ff46cf8b Add AlterIndexTogether operation 2013-07-02 18:02:01 +01:00
Andrew Godwin 9ef715d256 Fix some bad test running under PostgreSQL 2013-07-02 11:51:38 +01:00
Andrew Godwin 3b20af3e96 Autodetection of unique_together changes 2013-07-02 11:25:18 +01:00
Andrew Godwin 67dcea711e Add unique_together altering operation 2013-07-02 11:19:02 +01:00
Andrew Godwin e2d7e83256 Autodetect ForeignKeys and add dependencies/split on circulars 2013-06-22 17:15:51 +01:00
Andrew Godwin cca40703df Prompt about renames rather than doing them automatically 2013-06-21 15:32:15 +01:00
Andrew Godwin 92a10f5552 Autodetect field renames. HAHAHA. AHAHAHAHA. YES. 2013-06-20 16:02:43 +01:00
Andrew Godwin 47e4b86ddf Autodetect field alters 2013-06-20 15:19:30 +01:00
Andrew Godwin 80bdf68d6b Add AlterField and RenameField operations 2013-06-20 15:12:59 +01:00
Andrew Godwin 6f667999e1 Add operation that renames tables 2013-06-20 14:54:11 +01:00
Andrew Godwin ab5cbae9b7 First stab at some migration creation commands 2013-06-19 15:36:22 +01:00
Andrew Godwin 2ae8a8a77d Fix test running with new apps stuff/migrate actually running migrations 2013-06-19 15:36:02 +01:00
Andrew Godwin 91c470def5 Auto-naming for migrations and some writer fixes 2013-06-07 17:56:43 +01:00
Andrew Godwin cd809619a2 Autodetector tests 2013-06-07 15:49:48 +01:00
Andrew Godwin c7aa4b5338 Field encoding 2013-06-07 15:36:31 +01:00
Andrew Godwin 4492f06408 A bit of an autodetector and a bit of a writer 2013-06-07 15:28:38 +01:00
Andrew Godwin e6f7f4533c Add an Executor for end-to-end running 2013-05-30 18:08:58 +01:00
Andrew Godwin 7f9a0b7061 Fix graph tests 2013-05-30 17:56:53 +01:00
Andrew Godwin 05929ee89b Add the start of some operation tests 2013-05-30 17:55:59 +01:00
Andrew Godwin d0ecefc2c9 Start adding operations that work and tests for them 2013-05-29 17:47:10 +01:00
Andrew Godwin 264f8650e3 ModelState now freezes options and bases 2013-05-19 12:35:17 +02:00
Andrew Godwin 38a8cf1cdc Fix state tests a little 2013-05-18 18:30:34 +02:00
Andrew Godwin 7d041b9394 Split up test and make the State classes a bit better. 2013-05-18 13:49:56 +02:00
Andrew Godwin eb5e50215a Do some basic testing of the recorder 2013-05-10 16:18:19 +01:00
Andrew Godwin 8a1f017777 Add root_node and leaf_node functions to MigrationGraph 2013-05-10 16:09:57 +01:00
Andrew Godwin 9ce8354672 First phase of loading migrations from disk 2013-05-10 16:00:55 +01:00
Andrew Godwin f6801a234f Adding a dependency graph class and tests 2013-05-10 12:52:04 +01:00