Neater return_db pattern for reusing memory command, closes #643

tests/test_cli_memory.py

@@ -1,6 +1,6 @@
+import click
 import json
 import pytest
-import sys
 from click.testing import CliRunner
 
 from sqlite_utils import Database, cli
@@ -307,21 +307,14 @@ def test_memory_functions():
     assert result.output.strip() == '[{"hello()": "Hello"}]'
 
 
-@pytest.mark.parametrize("enabled", (False, True))
-def test_memory_named_database_hack(enabled):
+def test_memory_return_db(tmpdir):
     # https://github.com/simonw/sqlite-utils/issues/643
-    sys._sqlite_utils_memory_test = enabled
-    try:
-        result = CliRunner().invoke(
-            cli.cli,
-            ["memory", "-", "--analyze"],
-            input="id,name\n1,Cleo\n2,Bants",
-        )
-        assert result.exit_code == 0
-        db = Database(memory_name="sqlite_utils_memory")
-        if enabled:
-            assert db.table_names() == ["stdin"]
-        else:
-            assert db.table_names() == []
-    finally:
-        sys._sqlite_utils_memory_test = False
+    from sqlite_utils.cli import cli
+
+    path = str(tmpdir / "dogs.csv")
+    open(path, "w").write("id,name\n1,Cleo")
+
+    with click.Context(cli) as ctx:
+        db = ctx.invoke(cli.commands["memory"], paths=(path,), return_db=True)
+
+    assert db.table_names() == ["dogs"]