started adding integration tests for migrations

Author: dantownsend

piccolo/apps/migrations/auto/integration/README.md

@@ -0,0 +1,5 @@
+# Integration tests
+
+The integration tests are for testing the migrations end to end - from auto generating a migration file, to running it.
+
+Migrations are complex - columns can be added, deleted, renamed, and modified (likewise with tables). Migrations can also be run backwards. To properly test all of the possible options, we need a lot of test cases.

piccolo/apps/migrations/auto/integration/test_migrations.py

@@ -0,0 +1,75 @@
+import os
+import shutil
+import tempfile
+import time
+import typing as t
+from unittest import TestCase
+
+from piccolo.conf.apps import AppConfig
+from piccolo.columns.column_types import Varchar
+from piccolo.apps.migrations.commands.new import (
+    _create_new_migration,
+    _create_migrations_folder,
+)
+from piccolo.apps.migrations.commands.forwards import ForwardsMigrationManager
+from piccolo.table import Table, create_table_class
+from piccolo.utils.sync import run_sync
+
+
+class TestMigrations(TestCase):
+    def tearDown(self):
+        create_table_class("MyTable").alter().drop_table(if_exists=True)
+
+    def run_migrations(self, app_config: AppConfig):
+        manager = ForwardsMigrationManager(app_name=app_config.app_name)
+        run_sync(manager.create_migration_table())
+        run_sync(manager.run_migrations(app_config=app_config))
+
+    def _test_migrations(self, table_1: t.Type[Table], table_2: t.Type[Table]):
+        temp_directory_path = tempfile.gettempdir()
+        migrations_folder_path = os.path.join(
+            temp_directory_path, "piccolo_migrations"
+        )
+
+        if os.path.exists(migrations_folder_path):
+            shutil.rmtree(migrations_folder_path)
+
+        _create_migrations_folder(migrations_folder_path)
+
+        app_config = AppConfig(
+            app_name="test_app",
+            migrations_folder_path=migrations_folder_path,
+            table_classes=[table_1],
+        )
+
+        meta = run_sync(
+            _create_new_migration(app_config=app_config, auto=True)
+        )
+        self.assertTrue(os.path.exists(meta.migration_path))
+        self.run_migrations(app_config=app_config)
+
+        #######################################################################
+
+        # It's kind of absurd sleeping for 1 microsecond, but it guarantees
+        # the migration IDs will be unique, and just in case computers and / or
+        # Python get insanely fast in the future :)
+        time.sleep(1e-6)
+
+        #######################################################################
+
+        app_config.table_classes = [table_2]
+        meta = run_sync(
+            _create_new_migration(app_config=app_config, auto=True)
+        )
+        self.assertTrue(os.path.exists(meta.migration_path))
+        self.run_migrations(app_config=app_config)
+
+        # TODO - check the migrations ran correctly
+
+    def test_add_column(self):
+        table_1 = create_table_class("MyTable")
+        table_2 = create_table_class(
+            "MyTable", class_members={"name": Varchar()}
+        )
+
+        self._test_migrations(table_1=table_1, table_2=table_2)

piccolo/apps/migrations/commands/forwards.py

@@ -12,15 +12,17 @@
 
 
 class ForwardsMigrationManager(BaseMigrationManager):
-    def __init__(self, app_name: str, migration_id: str, fake: bool = False):
+    def __init__(
+        self, app_name: str, migration_id: str = "all", fake: bool = False
+    ):
         self.app_name = app_name
         self.migration_id = migration_id
         self.fake = fake
         super().__init__()
 
     async def run_migrations(self, app_config: AppConfig) -> MigrationResult:
         already_ran = await Migration.get_migrations_which_ran(
-            app_name=self.app_name
+            app_name=app_config.app_name
         )
 
         migration_modules: t.Dict[
@@ -67,7 +69,7 @@ async def run_migrations(self, app_config: AppConfig) -> MigrationResult:
                 print(f"-> Ran {_id}")
 
             await Migration.insert().add(
-                Migration(name=_id, app_name=self.app_name)
+                Migration(name=_id, app_name=app_config.app_name)
             ).run()
 
         return MigrationResult(success=True, message="Ran successfully")