rename Migrator before and after methods (#83)

Rename ``Migrator`` methods:

+ ``before`` to ``apply_initial_migration``
+ ``after`` to ``apply_tested_migration``

README.md

@@ -53,12 +53,13 @@ To test all migrations we have a [`Migrator`](https://github.com/wemake-services
 
 It has three methods to work with:
 
-- `.before()` which takes app and migration names to generate a state
-  before the actual migration happens.
-  It creates the `before state` by applying all migrations up to and including
-  the one passed as an argument.
+- `.apply_initial_migration()` which takes app and migration names to generate
+  a state before the actual migration happens. It creates the `before state`
+  by applying all migrations up to and including the ones passed as an argument.
+
+- `.apply_tested_migration()` which takes app and migration names to perform the
+  actual migration
 
-- `.after()` which takes app and migration names to perform the actual migration
 - `.reset()` to clean everything up after we are done with testing
 
 So, here's an example:
@@ -71,19 +72,21 @@ migrator = Migrator(database='default')
 # Initial migration, currently our model has only a single string field:
 # Note:
 # We are testing migration `0002_someitem_is_clean`, so we are specifying
-# the name of the previous migration (`0001_initial`) in the .before()
-# method in order to prepare a state of the database before applying
-# the migration we are going to test.
+# the name of the previous migration (`0001_initial`) in the
+# .apply_initial_migration() method in order to prepare a state of the database
+# before applying the migration we are going to test.
 #
-old_state = migrator.before(('main_app', '0001_initial'))
+old_state = migrator.apply_initial_migration(('main_app', '0001_initial'))
 SomeItem = old_state.apps.get_model('main_app', 'SomeItem')
 
 # Let's create a model with just a single field specified:
 SomeItem.objects.create(string_field='a')
 assert len(SomeItem._meta.get_fields()) == 2  # id + string_field
 
 # Now this migration will add `is_clean` field to the model:
-new_state = migrator.after(('main_app', '0002_someitem_is_clean'))
+new_state = migrator.apply_tested_migration(
+    ('main_app', '0002_someitem_is_clean'),
+)
 SomeItem = new_state.apps.get_model('main_app', 'SomeItem')
 
 # We can now test how our migration worked, new field is there:
@@ -105,14 +108,16 @@ Nothing really changes except migration names that you pass and your logic:
 migrator = Migrator()
 
 # Currently our model has two field, but we need a rollback:
-old_state = migrator.before(('main_app', '0002_someitem_is_clean'))
+old_state = migrator.apply_initial_migration(
+    ('main_app', '0002_someitem_is_clean'),
+)
 SomeItem = old_state.apps.get_model('main_app', 'SomeItem')
 
 # Create some data to illustrate your cases:
 # ...
 
 # Now this migration will drop `is_clean` field:
-new_state = migrator.after(('main_app', '0001_initial'))
+new_state = migrator.apply_tested_migration(('main_app', '0001_initial'))
 
 # Assert the results:
 # ...
@@ -170,13 +175,13 @@ import pytest
 @pytest.mark.django_db
 def test_pytest_plugin_initial(migrator):
     """Ensures that the initial migration works."""
-    old_state = migrator.before(('main_app', None))
+    old_state = migrator.apply_initial_migration(('main_app', None))
 
     with pytest.raises(LookupError):
         # Models does not yet exist:
         old_state.apps.get_model('main_app', 'SomeItem')
 
-    new_state = migrator.after(('main_app', '0001_initial'))
+    new_state = migrator.apply_tested_migration(('main_app', '0001_initial'))
     # After the initial migration is done, we can use the model state:
     SomeItem = new_state.apps.get_model('main_app', 'SomeItem')
     assert SomeItem.objects.filter(string_field='').count() == 0

django_test_migrations/contrib/pytest_plugin.py

@@ -16,8 +16,10 @@ def migrator_factory(request, transactional_db, django_db_use_migrations):
         @pytest.mark.django_db
         def test_migration(migrator_factory):
             migrator = migrator_factory('custom_db_alias')
-            old_state = migrator.before(('main_app', None))
-            new_state = migrator.after(('main_app', '0001_initial'))
+            old_state = migrator.apply_initial_migration(('main_app', None))
+            new_state = migrator.apply_tested_migration(
+                ('main_app', '0001_initial'),
+            )
 
             assert isinstance(old_state, ProjectState)
             assert isinstance(new_state, ProjectState)
@@ -55,8 +57,10 @@ def migrator(migrator_factory):  # noqa: WPS442
 
         @pytest.mark.django_db
         def test_migration(migrator):
-            old_state = migrator.before(('main_app', None))
-            new_state = migrator.after(('main_app', '0001_initial'))
+            old_state = migrator.apply_initial_migration(('main_app', None))
+            new_state = migrator.apply_tested_migration(
+                ('main_app', '0001_initial'),
+            )
 
             assert isinstance(old_state, ProjectState)
             assert isinstance(new_state, ProjectState)

django_test_migrations/contrib/unittest_case.py

@@ -31,9 +31,11 @@ def setUp(self) -> None:
         """
         super().setUp()
         self._migrator = Migrator(self.database_name)
-        self.old_state = self._migrator.before(self.migrate_from)
+        self.old_state = self._migrator.apply_initial_migration(
+            self.migrate_from,
+        )
         self.prepare()
-        self.new_state = self._migrator.after(self.migrate_to)
+        self.new_state = self._migrator.apply_tested_migration(self.migrate_to)
 
     def prepare(self) -> None:
         """

django_test_migrations/migrator.py

@@ -62,9 +62,9 @@ def __init__(
         self._database: str = database
         self._executor = MigrationExecutor(connections[self._database])
 
-    def before(self, migrate_from: MigrationSpec) -> ProjectState:
+    def apply_initial_migration(self, targets: MigrationSpec) -> ProjectState:
         """Reverse back to the original migration."""
-        migrate_from = normalize(migrate_from)
+        targets = normalize(targets)
 
         style = no_style()
         # start from clean database state
@@ -77,17 +77,17 @@ def before(self, migrate_from: MigrationSpec) -> ProjectState:
             self._executor.loader.graph.leaf_nodes(),
             clean_start=True,
         )
-        plan = truncate_plan(migrate_from, full_plan)
+        plan = truncate_plan(targets, full_plan)
 
         # apply all migrations from generated plan on clean database
         # (only forward, so any unexpected migration won't be applied)
         # to restore database state before tested migration
-        return self._migrate(migrate_from, plan=plan)
+        return self._migrate(targets, plan=plan)
 
-    def after(self, migrate_to: MigrationSpec) -> ProjectState:
+    def apply_tested_migration(self, targets: MigrationSpec) -> ProjectState:
         """Apply the next migration."""
         self._executor.loader.build_graph()  # reload
-        return self._migrate(normalize(migrate_to))
+        return self._migrate(normalize(targets))
 
     def reset(self) -> None:
         """Reset the state to the most recent one."""

tests/test_contrib/test_pytest_plugin/test_pytest_plugin_direct.py

@@ -12,13 +12,13 @@
 @pytest.mark.django_db
 def test_pytest_plugin_initial(migrator):
     """Ensures that the initial migration works."""
-    old_state = migrator.before(('main_app', None))
+    old_state = migrator.apply_initial_migration(('main_app', None))
 
     with pytest.raises(LookupError):
         # Models does not yet exist:
         old_state.apps.get_model('main_app', 'SomeItem')
 
-    new_state = migrator.after(('main_app', '0001_initial'))
+    new_state = migrator.apply_tested_migration(('main_app', '0001_initial'))
     # After the initial migration is done, we can use the model state:
     SomeItem = new_state.apps.get_model('main_app', 'SomeItem')
     assert SomeItem.objects.filter(string_field='').count() == 0
@@ -27,13 +27,15 @@ def test_pytest_plugin_initial(migrator):
 @pytest.mark.django_db
 def test_pytest_plugin0001(migrator):
     """Ensures that the first migration works."""
-    old_state = migrator.before(('main_app', '0001_initial'))
+    old_state = migrator.apply_initial_migration(('main_app', '0001_initial'))
     SomeItem = old_state.apps.get_model('main_app', 'SomeItem')
 
     with pytest.raises(FieldError):
         SomeItem.objects.filter(is_clean=True)
 
-    new_state = migrator.after(('main_app', '0002_someitem_is_clean'))
+    new_state = migrator.apply_tested_migration(
+        ('main_app', '0002_someitem_is_clean'),
+    )
     SomeItem = new_state.apps.get_model('main_app', 'SomeItem')
 
     assert SomeItem.objects.filter(is_clean=True).count() == 0
@@ -42,15 +44,19 @@ def test_pytest_plugin0001(migrator):
 @pytest.mark.django_db
 def test_pytest_plugin0002(migrator):
     """Ensures that the second migration works."""
-    old_state = migrator.before(('main_app', '0002_someitem_is_clean'))
+    old_state = migrator.apply_initial_migration(
+        ('main_app', '0002_someitem_is_clean'),
+    )
     SomeItem = old_state.apps.get_model('main_app', 'SomeItem')
     SomeItem.objects.create(string_field='a')
     SomeItem.objects.create(string_field='a b')
 
     assert SomeItem.objects.count() == 2
     assert SomeItem.objects.filter(is_clean=True).count() == 2
 
-    new_state = migrator.after(('main_app', '0003_update_is_clean'))
+    new_state = migrator.apply_tested_migration(
+        ('main_app', '0003_update_is_clean'),
+    )
     SomeItem = new_state.apps.get_model('main_app', 'SomeItem')
 
     assert SomeItem.objects.count() == 2
@@ -60,14 +66,18 @@ def test_pytest_plugin0002(migrator):
 @pytest.mark.django_db
 def test_pytest_plugin0003(migrator):
     """Ensures that the third migration works."""
-    old_state = migrator.before(('main_app', '0003_update_is_clean'))
+    old_state = migrator.apply_initial_migration(
+        ('main_app', '0003_update_is_clean'),
+    )
     SomeItem = old_state.apps.get_model('main_app', 'SomeItem')
     SomeItem.objects.create(string_field='a')  # default is still there
 
     assert SomeItem.objects.count() == 1
     assert SomeItem.objects.filter(is_clean=True).count() == 1
 
-    new_state = migrator.after(('main_app', '0004_auto_20191119_2125'))
+    new_state = migrator.apply_tested_migration(
+        ('main_app', '0004_auto_20191119_2125'),
+    )
     SomeItem = new_state.apps.get_model('main_app', 'SomeItem')
 
     with pytest.raises(IntegrityError):

tests/test_contrib/test_pytest_plugin/test_pytest_plugin_reverse.py

@@ -12,12 +12,14 @@
 @pytest.mark.django_db
 def test_pytest_plugin0001(migrator):
     """Ensures that the first migration works."""
-    old_state = migrator.before(('main_app', '0002_someitem_is_clean'))
+    old_state = migrator.apply_initial_migration(
+        ('main_app', '0002_someitem_is_clean'),
+    )
     SomeItem = old_state.apps.get_model('main_app', 'SomeItem')
 
     assert SomeItem.objects.filter(is_clean=True).count() == 0
 
-    new_state = migrator.after(('main_app', '0001_initial'))
+    new_state = migrator.apply_tested_migration(('main_app', '0001_initial'))
     SomeItem = new_state.apps.get_model('main_app', 'SomeItem')
 
     with pytest.raises(FieldError):
@@ -27,15 +29,19 @@ def test_pytest_plugin0001(migrator):
 @pytest.mark.django_db
 def test_pytest_plugin0002(migrator):
     """Ensures that the second migration works."""
-    old_state = migrator.before(('main_app', '0003_update_is_clean'))
+    old_state = migrator.apply_initial_migration(
+        ('main_app', '0003_update_is_clean'),
+    )
     SomeItem = old_state.apps.get_model('main_app', 'SomeItem')
     SomeItem.objects.create(string_field='a', is_clean=True)
     SomeItem.objects.create(string_field='a b', is_clean=False)
 
     assert SomeItem.objects.count() == 2
     assert SomeItem.objects.filter(is_clean=True).count() == 1
 
-    new_state = migrator.after(('main_app', '0002_someitem_is_clean'))
+    new_state = migrator.apply_tested_migration(
+        ('main_app', '0002_someitem_is_clean'),
+    )
     SomeItem = new_state.apps.get_model('main_app', 'SomeItem')
 
     assert SomeItem.objects.count() == 2

tests/test_migrator/test_migrator.py

@@ -8,8 +8,8 @@
 def test_migrator(transactional_db):
     """We only need this test for coverage."""
     migrator = Migrator()
-    old_state = migrator.before(('main_app', None))
-    new_state = migrator.after(('main_app', '0001_initial'))
+    old_state = migrator.apply_initial_migration(('main_app', None))
+    new_state = migrator.apply_tested_migration(('main_app', '0001_initial'))
 
     assert isinstance(old_state, ProjectState)
     assert isinstance(new_state, ProjectState)
@@ -20,8 +20,8 @@ def test_migrator(transactional_db):
 def test_migrator_list(transactional_db):
     """We only need this test for coverage."""
     migrator = Migrator()
-    old_state = migrator.before([('main_app', None)])
-    new_state = migrator.after([('main_app', '0001_initial')])
+    old_state = migrator.apply_initial_migration([('main_app', None)])
+    new_state = migrator.apply_tested_migration([('main_app', '0001_initial')])
 
     assert isinstance(old_state, ProjectState)
     assert isinstance(new_state, ProjectState)