Backported CliRunner fix from e3eb356a

Removed obsolete mix_stderr=False arguments from CliRunner() calls
which are not supported in Click 8.3.0.

tests/test_cli.py

@@ -193,7 +193,7 @@ def test_version():
 
 @pytest.mark.parametrize("invalid_port", ["-1", "0.5", "dog", "65536"])
 def test_serve_invalid_ports(invalid_port):
-    runner = CliRunner(mix_stderr=False)
+    runner = CliRunner()
     result = runner.invoke(cli, ["--port", invalid_port])
     assert result.exit_code == 2
     assert "Invalid value for '-p'" in result.stderr
@@ -209,7 +209,7 @@ def test_setting():
 
 
 def test_setting_type_validation():
-    runner = CliRunner(mix_stderr=False)
+    runner = CliRunner()
     result = runner.invoke(cli, ["--setting", "default_page_size", "dog"])
     assert result.exit_code == 2
     assert '"default_page_size" should be an integer' in result.stderr
@@ -239,17 +239,20 @@ def test_setting_default_allow_sql(default_allow_sql):
 
 def test_config_deprecated():
     # The --config option should show a deprecation message
-    runner = CliRunner(mix_stderr=False)
+    runner = CliRunner()
     result = runner.invoke(
         cli, ["--config", "allow_download:off", "--get", "/-/settings.json"]
     )
     assert result.exit_code == 0
-    assert not json.loads(result.output)["allow_download"]
-    assert "will be deprecated in" in result.stderr
+    # Extract JSON from output (skip the deprecation warning line)
+    output_lines = result.output.strip().split("\n")
+    json_output = "\n".join(line for line in output_lines if line.startswith("{"))
+    assert not json.loads(json_output)["allow_download"]
+    assert "will be deprecated in" in result.output
 
 
 def test_sql_errors_logged_to_stderr():
-    runner = CliRunner(mix_stderr=False)
+    runner = CliRunner()
     result = runner.invoke(cli, ["--get", "/_memory.json?sql=select+blah"])
     assert result.exit_code == 1
     assert "sql = 'select blah', params = {}: no such column: blah\n" in result.stderr

tests/test_config_dir.py

@@ -114,7 +114,7 @@ def test_settings(config_dir_client):
 def test_error_on_config_json(tmp_path_factory):
     config_dir = tmp_path_factory.mktemp("config-dir")
     (config_dir / "config.json").write_text(json.dumps(SETTINGS), "utf-8")
-    runner = CliRunner(mix_stderr=False)
+    runner = CliRunner()
     result = runner.invoke(cli, [str(config_dir), "--get", "/-/settings.json"])
     assert result.exit_code == 1
     assert "config.json should be renamed to settings.json" in result.stderr

tests/test_crossdb.py

@@ -44,7 +44,7 @@ def test_crossdb_warning_if_too_many_databases(tmp_path_factory):
         conn = sqlite3.connect(path)
         conn.execute("vacuum")
         dbs.append(path)
-    runner = CliRunner(mix_stderr=False)
+    runner = CliRunner()
     result = runner.invoke(
         cli,
         [