xfstestsdb: Create a generic Command class

This is intended to be used as a base class for implementing other
xfstestsdb commands.

Signed-off-by: Anna Schumaker <anna@nowheycreamery.com>

tests/test_commands.py

@@ -0,0 +1,32 @@
+# Copyright 2023 (c) Anna Schumaker.
+"""Tests the generic Command class."""
+import argparse
+import unittest
+import xfstestsdb.commands
+
+
+class TestCommand(unittest.TestCase):
+    """Tests the xfstestsdb Command class."""
+
+    def setUp(self):
+        """Set up common variables."""
+        self.sql = xfstestsdb.sqlite.Connection()
+        self.parser = argparse.ArgumentParser()
+        self.subparser = self.parser.add_subparsers(title="commands")
+        self.command = xfstestsdb.commands.Command(self.subparser, self.sql,
+                                                   "test", "help text",
+                                                   description="description")
+
+    def test_init(self):
+        """Test that the Command was initialized properly."""
+        self.assertIsInstance(self.command.parser, argparse.ArgumentParser)
+        self.assertEqual(self.subparser.choices["test"], self.command.parser)
+        self.assertEqual(self.command.parser.description, "description")
+        self.assertEqual(self.command.parser._defaults["function"],
+                         self.command.do_command)
+        self.assertEqual(self.command.sql, self.sql)
+
+    def test_do_command(self):
+        """Test the do_command() function."""
+        with self.assertRaises(NotImplementedError):
+            self.command.do_command(argparse.Namespace())

xfstestsdb/commands.py

@@ -0,0 +1,19 @@
+# Copyright 2023 (c) Anna Schumaker.
+"""A generic Command class."""
+import argparse
+from . import sqlite
+
+
+class Command:
+    """A class to help implement xfstestsdb subcommands."""
+
+    def __init__(self, subparser: argparse.Action, sql: sqlite.Connection,
+                 name: str, help: str, **kwargs) -> None:
+        """Set up the Command."""
+        self.parser = subparser.add_parser(name, help=help, **kwargs)
+        self.parser.set_defaults(function=self.do_command)
+        self.sql = sql
+
+    def do_command(self, args: argparse.Namespace) -> None:
+        """Do something."""
+        raise NotImplementedError