"""Tests for CLI argument parsing and configuration resolution.
This module tests the command-line interface for mcp-test-mcp, including:
- Argument parsing for --transport, --host, --port
- Environment variable handling (MCP_TEST_TRANSPORT, MCP_TEST_HOST, MCP_TEST_PORT)
- Priority resolution (CLI > env var > default)
"""
import os
from unittest import mock
import pytest
from mcp_test_mcp.__main__ import (
DEFAULT_HOST,
DEFAULT_PORT,
DEFAULT_TRANSPORT,
VALID_TRANSPORTS,
get_config_value,
get_port_value,
parse_args,
resolve_config,
)
class TestParseArgs:
"""Tests for parse_args function."""
def test_no_args_returns_defaults(self):
"""With no arguments, all values should be None (to allow env var fallback)."""
args = parse_args([])
assert args.transport is None
assert args.host is None
assert args.port is None
def test_transport_stdio(self):
"""--transport stdio should be accepted."""
args = parse_args(["--transport", "stdio"])
assert args.transport == "stdio"
def test_transport_streamable_http(self):
"""--transport streamable-http should be accepted."""
args = parse_args(["--transport", "streamable-http"])
assert args.transport == "streamable-http"
def test_transport_sse(self):
"""--transport sse should be accepted."""
args = parse_args(["--transport", "sse"])
assert args.transport == "sse"
def test_transport_short_flag(self):
"""Short flag -t should work for transport."""
args = parse_args(["-t", "streamable-http"])
assert args.transport == "streamable-http"
def test_invalid_transport_exits(self):
"""Invalid transport should cause argparse to exit."""
with pytest.raises(SystemExit):
parse_args(["--transport", "invalid"])
def test_host_argument(self):
"""--host should set the host value."""
args = parse_args(["--host", "0.0.0.0"])
assert args.host == "0.0.0.0"
def test_host_short_flag(self):
"""Short flag -H should work for host."""
args = parse_args(["-H", "192.168.1.1"])
assert args.host == "192.168.1.1"
def test_port_argument(self):
"""--port should set the port value as integer."""
args = parse_args(["--port", "9000"])
assert args.port == 9000
assert isinstance(args.port, int)
def test_port_short_flag(self):
"""Short flag -p should work for port."""
args = parse_args(["-p", "8080"])
assert args.port == 8080
def test_invalid_port_exits(self):
"""Non-integer port should cause argparse to exit."""
with pytest.raises(SystemExit):
parse_args(["--port", "not-a-number"])
def test_all_arguments_combined(self):
"""All arguments should work together."""
args = parse_args([
"--transport", "streamable-http",
"--host", "0.0.0.0",
"--port", "8080"
])
assert args.transport == "streamable-http"
assert args.host == "0.0.0.0"
assert args.port == 8080
class TestGetConfigValue:
"""Tests for get_config_value function."""
def test_cli_value_takes_precedence(self):
"""CLI value should take precedence over env var and default."""
with mock.patch.dict(os.environ, {"TEST_VAR": "env_value"}):
result = get_config_value("cli_value", "TEST_VAR", "default_value")
assert result == "cli_value"
def test_env_var_used_when_no_cli(self):
"""Env var should be used when CLI value is None."""
with mock.patch.dict(os.environ, {"TEST_VAR": "env_value"}):
result = get_config_value(None, "TEST_VAR", "default_value")
assert result == "env_value"
def test_default_used_when_no_cli_or_env(self):
"""Default should be used when CLI and env var are not set."""
with mock.patch.dict(os.environ, {}, clear=True):
# Ensure the env var is not set
os.environ.pop("TEST_VAR", None)
result = get_config_value(None, "TEST_VAR", "default_value")
assert result == "default_value"
def test_empty_string_cli_value_is_used(self):
"""Empty string CLI value should be used (not fallback to env)."""
with mock.patch.dict(os.environ, {"TEST_VAR": "env_value"}):
result = get_config_value("", "TEST_VAR", "default_value")
assert result == ""
class TestGetPortValue:
"""Tests for get_port_value function."""
def test_cli_value_takes_precedence(self):
"""CLI port value should take precedence over env var and default."""
with mock.patch.dict(os.environ, {"TEST_PORT": "9000"}):
result = get_port_value(8080, "TEST_PORT", 8000)
assert result == 8080
def test_env_var_used_when_no_cli(self):
"""Env var should be used when CLI value is None."""
with mock.patch.dict(os.environ, {"TEST_PORT": "9000"}):
result = get_port_value(None, "TEST_PORT", 8000)
assert result == 9000
def test_default_used_when_no_cli_or_env(self):
"""Default should be used when CLI and env var are not set."""
with mock.patch.dict(os.environ, {}, clear=True):
os.environ.pop("TEST_PORT", None)
result = get_port_value(None, "TEST_PORT", 8000)
assert result == 8000
def test_invalid_env_var_returns_default(self, capsys):
"""Invalid env var port should fall back to default with warning."""
with mock.patch.dict(os.environ, {"TEST_PORT": "not-a-number"}):
result = get_port_value(None, "TEST_PORT", 8000)
assert result == 8000
# Check warning was printed
captured = capsys.readouterr()
assert "Warning" in captured.err
assert "not-a-number" in captured.err
class TestResolveConfig:
"""Tests for resolve_config function."""
def test_all_defaults(self):
"""With no CLI args or env vars, defaults should be used."""
# Clear relevant environment variables
env_patch = {
k: v for k, v in os.environ.items()
if not k.startswith("MCP_TEST_")
}
with mock.patch.dict(os.environ, env_patch, clear=True):
args = parse_args([])
config = resolve_config(args)
assert config["transport"] == DEFAULT_TRANSPORT
assert config["host"] == DEFAULT_HOST
assert config["port"] == DEFAULT_PORT
def test_cli_args_take_precedence(self):
"""CLI args should override env vars."""
with mock.patch.dict(os.environ, {
"MCP_TEST_TRANSPORT": "sse",
"MCP_TEST_HOST": "10.0.0.1",
"MCP_TEST_PORT": "7000"
}):
args = parse_args([
"--transport", "streamable-http",
"--host", "0.0.0.0",
"--port", "8080"
])
config = resolve_config(args)
assert config["transport"] == "streamable-http"
assert config["host"] == "0.0.0.0"
assert config["port"] == 8080
def test_env_vars_used_when_no_cli(self):
"""Env vars should be used when CLI args not provided."""
with mock.patch.dict(os.environ, {
"MCP_TEST_TRANSPORT": "streamable-http",
"MCP_TEST_HOST": "192.168.1.100",
"MCP_TEST_PORT": "9000"
}):
args = parse_args([])
config = resolve_config(args)
assert config["transport"] == "streamable-http"
assert config["host"] == "192.168.1.100"
assert config["port"] == 9000
def test_invalid_transport_from_env_exits(self):
"""Invalid transport from env var should cause exit."""
with mock.patch.dict(os.environ, {"MCP_TEST_TRANSPORT": "invalid"}):
args = parse_args([])
with pytest.raises(SystemExit):
resolve_config(args)
def test_mixed_cli_and_env(self):
"""CLI and env vars can be mixed."""
with mock.patch.dict(os.environ, {
"MCP_TEST_HOST": "10.0.0.1",
"MCP_TEST_PORT": "7000"
}):
args = parse_args(["--transport", "streamable-http"])
config = resolve_config(args)
assert config["transport"] == "streamable-http" # From CLI
assert config["host"] == "10.0.0.1" # From env
assert config["port"] == 7000 # From env
class TestValidTransports:
"""Tests to ensure all documented transports are valid."""
def test_stdio_is_valid(self):
"""stdio should be a valid transport."""
assert "stdio" in VALID_TRANSPORTS
def test_streamable_http_is_valid(self):
"""streamable-http should be a valid transport."""
assert "streamable-http" in VALID_TRANSPORTS
def test_sse_is_valid(self):
"""sse should be a valid transport."""
assert "sse" in VALID_TRANSPORTS
def test_default_is_stdio(self):
"""Default transport should be stdio."""
assert DEFAULT_TRANSPORT == "stdio"
def test_default_host(self):
"""Default host should be localhost."""
assert DEFAULT_HOST == "127.0.0.1"
def test_default_port(self):
"""Default port should be 8000."""
assert DEFAULT_PORT == 8000
