Ensure one db instance only

Ensure testing db is correctly set to sqlite

.envrc

@@ -4,17 +4,17 @@ export MAIL_PORT=587
 export MAIL_SERVER="smtp.fastmail.com"
 export MAIL_USERNAME="kae@midnighthax.com"
 export MAIL_USE_TLS=True
-export PYGAME_HIDE_SUPPORT_PROMPT=1
 branch=$(git branch --show-current)
+
 # Always treat running from /home/kae/mm as production
 if [ $(pwd) == /home/kae/mm ]; then
         export MM_ENV="PRODUCTION"
-        export ALCHEMICAL_DATABASE_URI="mysql+mysqldb://musicmuster:musicmuster@localhost/musicmuster_prod"
+        export DATABASE_URL="mysql+mysqldb://musicmuster:musicmuster@localhost/musicmuster_prod"
 elif on_git_branch master; then
         export MM_ENV="PRODUCTION"
-        export ALCHEMICAL_DATABASE_URI="mysql+mysqldb://musicmuster:musicmuster@localhost/musicmuster_prod"
+        export DATABASE_URL="mysql+mysqldb://musicmuster:musicmuster@localhost/musicmuster_prod"
 else
         export MM_ENV="DEVELOPMENT"
-        export ALCHEMICAL_DATABASE_URI="mysql+mysqldb://dev_musicmuster:dev_musicmuster@localhost/dev_musicmuster"
+        export DATABASE_URL="mysql+mysqldb://dev_musicmuster:dev_musicmuster@localhost/dev_musicmuster"
         export PYTHONBREAKPOINT="pudb.set_trace"
 fi

app/dbmanager.py

@@ -0,0 +1,30 @@
+# Standard library imports
+
+# PyQt imports
+
+# Third party imports
+from alchemical import Alchemical  # type:ignore
+
+# App imports
+
+
+class DatabaseManager:
+    """
+    Singleton class to ensure we only ever have one db object
+    """
+
+    __instance = None
+
+    def __init__(self, database_url, **kwargs):
+        if DatabaseManager.__instance is None:
+            self.db = Alchemical(database_url, **kwargs)
+            self.db.create_all()
+            DatabaseManager.__instance = self
+        else:
+            raise Exception("Attempted to create a second DatabaseManager instance")
+
+    @staticmethod
+    def get_instance(database_url, **kwargs):
+        if DatabaseManager.__instance is None:
+            DatabaseManager(database_url, **kwargs)
+        return DatabaseManager.__instance

app/models.py

@@ -8,7 +8,6 @@ import sys
 # PyQt imports
 
 # Third party imports
-from alchemical import Alchemical  # type:ignore
 from sqlalchemy import (
     bindparam,
     delete,
@@ -22,18 +21,20 @@ from sqlalchemy.orm import joinedload
 from sqlalchemy.orm.session import Session
 
 # App imports
+from dbmanager import DatabaseManager
 import dbtables
 from config import Config
 from log import log
 
 
 # Establish database connection
-ALCHEMICAL_DATABASE_URI = os.environ.get("ALCHEMICAL_DATABASE_URI")
-if ALCHEMICAL_DATABASE_URI is None:
-    raise ValueError("ALCHEMICAL_DATABASE_URI is undefined")
-if "unittest" in sys.modules and "sqlite" not in ALCHEMICAL_DATABASE_URI:
+DATABASE_URL = os.environ.get("DATABASE_URL")
+if DATABASE_URL is None:
+    raise ValueError("DATABASE_URL is undefined")
+if "unittest" in sys.modules and "sqlite" not in DATABASE_URL:
     raise ValueError("Unit tests running on non-Sqlite database")
-db = Alchemical(ALCHEMICAL_DATABASE_URI, engine_options=Config.ENGINE_OPTIONS)
+db = DatabaseManager.get_instance(DATABASE_URL, engine_options=Config.ENGINE_OPTIONS).db
+db.create_all()
 
 
 # Database classes

tests/__init__.py

@@ -0,0 +1,14 @@
+# Standard library imports
+import os
+
+# PyQt imports
+
+# Third party imports
+
+# App imports
+# Set up test database before importing db
+# https://blog.miguelgrinberg.com/post/how-to-write-unit-tests-in-python-part-3-web-applications
+DB_FILE = "/tmp/mm.db"
+if os.path.exists(DB_FILE):
+    os.unlink(DB_FILE)
+os.environ["DATABASE_URL"] = "sqlite:///" + DB_FILE

tests/test_misc.py

@@ -1,5 +1,4 @@
 # Standard library imports
-import os
 import unittest
 
 # PyQt imports
@@ -8,15 +7,7 @@ import unittest
 import pytest
 
 # App imports
-# Set up test database before importing db
-# Mark subsequent lines to ignore E402, imports not at top of file
-# Set up test database before importing db
-# Mark subsequent lines to ignore E402, imports not at top of file
-DB_FILE = "/tmp/mm.db"
-if os.path.exists(DB_FILE):
-    os.unlink(DB_FILE)
-os.environ["ALCHEMICAL_DATABASE_URI"] = "sqlite:///" + DB_FILE
-from models import db, Settings  # noqa: E402
+from app.models import db, Settings
 
 
 class TestMMMisc(unittest.TestCase):

tests/test_models.py

@@ -1,6 +1,5 @@
 # Standard library imports
 import datetime as dt
-import os
 import unittest
 
 # PyQt imports
@@ -10,13 +9,7 @@ import unittest
 # App imports
 from app import helpers
 
-# Set up test database before importing db
-# Mark subsequent lines to ignore E402, imports not at top of file
-DB_FILE = "/tmp/mm.db"
-if os.path.exists(DB_FILE):
-    os.unlink(DB_FILE)
-os.environ["ALCHEMICAL_DATABASE_URI"] = "sqlite:///" + DB_FILE
-from app.models import (  # noqa: E402
+from app.models import (
     db,
     NoteColours,
     Playdates,

tests/test_playlistmodel.py

@@ -1,5 +1,4 @@
 # Standard library imports
-import os
 import unittest
 
 # PyQt imports
@@ -9,15 +8,8 @@ from PyQt6.QtCore import Qt, QModelIndex
 
 # App imports
 from app.helpers import get_all_track_metadata
-
-# Set up test database before importing db
-# Mark subsequent lines to ignore E402, imports not at top of file
-DB_FILE = "/tmp/mm.db"
-if os.path.exists(DB_FILE):
-    os.unlink(DB_FILE)
-os.environ["ALCHEMICAL_DATABASE_URI"] = "sqlite:///" + DB_FILE
-from app import playlistmodel  # noqa: E402
-from app.models import (  # noqa: E402
+from app import playlistmodel
+from app.models import (
     db,
     Playlists,
     Tracks,

tests/test_ui.py

@@ -3,22 +3,19 @@ import os
 import unittest
 
 # PyQt imports
+from PyQt6.QtCore import Qt
+from PyQt6.QtGui import QColor
 
 # Third party imports
 import pytest
 from pytestqt.plugin import QtBot  # type: ignore
 
 # App imports
-
-# Set up test database before importing db
-# Mark subsequent lines to ignore E402, imports not at top of file
-DB_FILE = "/tmp/mm.db"
-if os.path.exists(DB_FILE):
-    os.unlink(DB_FILE)
-os.environ["ALCHEMICAL_DATABASE_URI"] = "sqlite:///" + DB_FILE
+from config import Config
 from app import playlistmodel, utilities
-from app.models import (  # noqa: E402
+from app.models import (
     db,
+    NoteColours,
     Playlists,
     Tracks,
 )