Make program downward compatible until python 3.7

Add multi-version tests with nox to keep regressions from happening.

src/habitmove/__init__.py

@@ -1,9 +1,9 @@
 # init.py
 import sys
 
-if sys.version_info >= (3, 8):
+try:
     from importlib.metadata import version as metadata_version
-else:
+except ImportError:
     from importlib_metadata import version as metadata_version
 
 __version__ = str(metadata_version(__name__))

src/habitmove/habits.py

@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 import sqlite3
 
 from habitmove.nomiedata import Tracker

src/habitmove/nomiedata.py

@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 from typing import Any, Union
 from dataclasses import dataclass, field
 import re

src/habitmove/repetitions.py

@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 import sqlite3
 from typing import Optional
 from datetime import datetime
@@ -92,7 +94,8 @@ def add_to_database(
                     (sql_id, repetition.timestamp, repetition.value),
                 )
             except sqlite3.IntegrityError:
-                # TODO better error handling
+                # FIXME better error handling
+                # TODO think about adapting this to allow importing into existing databases
                 print(
                     f"{sql_id}, {habit.name}: timestamp {datetime.fromtimestamp(repetition.timestamp/1000)} not unique, moving timestamp slightly."
                 )

src/habitmove/schema.py

@@ -1,7 +1,8 @@
 import sqlite3
+import sys
 
 
-def create_database(name):
+def create_database(db_file: str = ":memory:") -> sqlite3.Connection:
     """create a database connection to the SQLite database
         specified by db_file
     :param db_file: database file
@@ -9,16 +10,14 @@ def create_database(name):
     """
     conn = None
     try:
-        conn = sqlite3.connect(name)
+        conn = sqlite3.connect(db_file)
         return conn
     except sqlite3.Error as e:
         print(e)
-
-    return conn
+        sys.exit(1)
 
 
-def create_tables(db):
-    c = db.cursor()
+def create_tables(c: sqlite3.Cursor):
     c.execute(
         """ CREATE TABLE IF NOT EXISTS Habits (
                                         id integer PRIMARY KEY AUTOINCREMENT,
@@ -51,8 +50,7 @@ def create_tables(db):
     )
 
 
-def create_constraints(db):
-    c = db.cursor()
+def create_constraints(c: sqlite3.Cursor):
     c.execute(
         """ CREATE UNIQUE INDEX IF NOT EXISTS idx_repetitions_habit_timestamp 
             on Repetitions( habit, timestamp);
@@ -60,15 +58,15 @@ def create_constraints(db):
     )
 
 
-def create_pragma(db):
-    c = db.cursor()
+def create_pragma(c: sqlite3.Cursor):
     c.execute(""" PRAGMA user_version = 24; """)
     c.execute(""" PRAGMA schema_version = 30; """)
 
 
-def migrate(name):
-    db = create_database(name)
-    create_tables(db)
-    create_constraints(db)
-    create_pragma(db)
+def migrate(fname):
+    db = create_database(fname)
+    c = db.cursor()
+    create_tables(c)
+    create_constraints(c)
+    create_pragma(c)
     return db