Add tests

src/tribler/core/upgrade/tribler_db/conftest.py

@@ -0,0 +1,17 @@
+import pytest
+
+from tribler.core.components.database.db.tribler_database import TriblerDatabase
+from tribler.core.upgrade.tribler_db.migration_chain import TriblerDatabaseMigrationChain
+from tribler.core.utilities.path_util import Path
+from tribler.core.utilities.simpledefs import STATEDIR_DB_DIR
+
+
+# pylint: disable=redefined-outer-name
+
+
+@pytest.fixture
+def migration_chain(tmpdir):
+    db_file_name = Path(tmpdir) / STATEDIR_DB_DIR / 'tribler.db'
+    db_file_name.parent.mkdir()
+    TriblerDatabase(filename=str(db_file_name))
+    return TriblerDatabaseMigrationChain(state_dir=Path(tmpdir), chain=[])

src/tribler/core/upgrade/tribler_db/scheme_migrations/tests/test_scheme_migration_0.py

@@ -0,0 +1,13 @@
+from tribler.core.upgrade.tribler_db.migration_chain import TriblerDatabaseMigrationChain
+from tribler.core.upgrade.tribler_db.scheme_migrations.scheme_migration_0 import scheme_migration_0
+from tribler.core.utilities.pony_utils import db_session
+
+
+@db_session
+def test_scheme_migration_0(migration_chain: TriblerDatabaseMigrationChain):
+    """ Test that the scheme_migration_0 changes the database version to 1. """
+    migration_chain.db.version = 0
+    migration_chain.migrations = [scheme_migration_0]
+
+    assert migration_chain.execute()
+    assert migration_chain.db.version == 1

src/tribler/core/upgrade/tribler_db/tests/test_migration_chain.py

@@ -2,30 +2,21 @@
 
 import pytest
 
-from tribler.core.components.database.db.tribler_database import TriblerDatabase
 from tribler.core.upgrade.tribler_db.decorator import migration
 from tribler.core.upgrade.tribler_db.migration_chain import TriblerDatabaseMigrationChain
 from tribler.core.utilities.path_util import Path
 from tribler.core.utilities.pony_utils import db_session
-from tribler.core.utilities.simpledefs import STATEDIR_DB_DIR
-
-
-@pytest.fixture
-def migration_chain(tmpdir):
-    db_file_name = Path(tmpdir) / STATEDIR_DB_DIR / 'tribler.db'
-    db_file_name.parent.mkdir()
-    TriblerDatabase(filename=str(db_file_name))
-    return TriblerDatabaseMigrationChain(state_dir=Path(tmpdir), chain=[])
 
 
 def test_db_does_not_exist(tmpdir):
+    """ Test that the migration chain does not execute if the database does not exist."""
     tribler_db_migration = TriblerDatabaseMigrationChain(state_dir=Path(tmpdir))
     assert not tribler_db_migration.execute()
 
 
 @db_session
 def test_db_execute(migration_chain: TriblerDatabaseMigrationChain):
-    # create a migration
+    """ Test that the migration chain executes all the migrations step by step."""
     migration3_call = Mock()
     migration_chain.db.version = 0
 
@@ -42,7 +33,7 @@ def migration3(*_, **__):
         migration3_call()
 
     @migration(execute_only_if_version=99, set_after_successful_execution_version=100)
-    def migration99(*_, **__):
+    def migration99(*_, **__):  # this migration should be skipped
         ...
 
     migration_chain.migrations = [
@@ -80,6 +71,8 @@ def migration99(*_, **__):
 
 @db_session
 def test_db_execute_no_annotation(migration_chain: TriblerDatabaseMigrationChain):
+    """ Test that the migration chain raises the NotImplementedError if the migration does not have the annotation."""
+
     def migration_without_annotation(*_, **__):
         ...