import diagnostics_channel from 'node:diagnostics_channel';
import { getLoggerOptions, setOptions } from '../options.context';
import { toMcpLevel, registerMcpSubscriber, createServerLogger } from '../server.logger';
import { log } from '../logger';
describe('toMcpLevel', () => {
it.each([
{
description: 'default',
level: undefined
},
{
description: 'debug',
level: 'debug'
},
{
description: 'info',
level: 'info'
},
{
description: 'warn',
level: 'warn'
},
{
description: 'error',
level: 'error'
},
{
description: 'anything',
level: 'lorem ipsum'
}
])('should return log severity, $description', ({ level }) => {
expect(toMcpLevel(level as any)).toMatchSnapshot();
});
});
describe('registerMcpSubscriber', () => {
let subscribeSpy: jest.SpyInstance;
let unsubscribeSpy: jest.SpyInstance;
beforeEach(() => {
setOptions({});
subscribeSpy = jest.spyOn(diagnostics_channel, 'subscribe');
unsubscribeSpy = jest.spyOn(diagnostics_channel, 'unsubscribe');
});
afterEach(() => {
subscribeSpy.mockRestore();
unsubscribeSpy.mockRestore();
});
it('should attempt to subscribe and unsubscribe from a channel', () => {
const loggingSession = getLoggerOptions();
const unsubscribe = registerMcpSubscriber((() => {}) as any, loggingSession);
unsubscribe();
expect({
subscribe: subscribeSpy.mock.calls,
unsubscribe: unsubscribeSpy.mock.calls
}).toMatchSnapshot('subscribe');
});
});
describe('createServerLogger', () => {
let subscribeSpy: jest.SpyInstance;
let unsubscribeSpy: jest.SpyInstance;
beforeEach(() => {
setOptions({});
subscribeSpy = jest.spyOn(diagnostics_channel, 'subscribe');
unsubscribeSpy = jest.spyOn(diagnostics_channel, 'unsubscribe');
});
afterEach(() => {
subscribeSpy.mockRestore();
unsubscribeSpy.mockRestore();
});
it.each([
{
description: 'with stderr, and emulated channel to pass checks',
options: { channelName: 'loremIpsum', stderr: true, protocol: false }
},
{
description: 'with stderr, protocol, and emulated channel to pass checks',
options: { channelName: 'loremIpsum', stderr: true, protocol: true }
},
{
description: 'with no logging options',
options: {},
stderr: false
}
])('should attempt to subscribe and unsubscribe from a channel, $description', ({ options }) => {
// Use channelName to pass conditions
const { unsubscribe } = createServerLogger((() => {}) as any, options as any);
unsubscribe();
expect({
subscribe: subscribeSpy.mock.calls,
unsubscribe: unsubscribeSpy.mock.calls
}).toMatchSnapshot('subscribe');
});
it('should return a memoized server logger that avoids duplicate sinks; teardown stops emissions', () => {
setOptions({ logging: { stderr: true, level: 'debug' } as any });
const stderrSpy = jest.spyOn(process.stderr, 'write').mockImplementation(() => true as any);
class MockServer { sendLoggingMessage = jest.fn(async () => {}); }
const server = new MockServer() as any;
// Create a single memoized server logger with two server-level subscription handlers
const { subscribe: subscribeCallOne, unsubscribe: unsubscribeAllCallOne } = createServerLogger.memo(server);
const { subscribe: subscribeCallTwo, unsubscribe: unsubscribeAllCallTwo } = createServerLogger.memo(server);
// Create two lower-level subscription handlers
const mockHandlerOne = jest.fn();
const mockHandlerTwo = jest.fn();
const unsubscribeMockHandlerOne = subscribeCallOne(mockHandlerOne);
const unsubscribeMockHandlerTwo = subscribeCallTwo(mockHandlerTwo);
log.debug('a');
expect(mockHandlerOne).toHaveBeenCalledTimes(1);
expect(mockHandlerTwo).toHaveBeenCalledTimes(1);
// This removes the subscription for mockHandlerOne
unsubscribeMockHandlerOne();
log.debug('b');
// This was removed earlier by the "unsubscribeMockHandlerOne()" call above
expect(mockHandlerOne).toHaveBeenCalledTimes(1);
// This continues to be called
expect(mockHandlerTwo).toHaveBeenCalledTimes(2);
log.info('lorem ipsum, dolor sit info');
expect(unsubscribeAllCallOne).toBe(unsubscribeAllCallTwo);
log.info('dolor sit amet');
// This removes all subscriptions
unsubscribeAllCallOne();
log.info('hello world!');
// This shouldn't throw an error since all subscriptions were removed
unsubscribeAllCallTwo();
log.debug('c');
// This was removed earlier by the "unsubscribeMockHandlerOne()" call above
expect(mockHandlerOne).toHaveBeenCalledTimes(1);
// This was removed by the "unsubscribeAllCallOne()" call above
expect(mockHandlerTwo).toHaveBeenCalledTimes(4);
// This shouldn't throw an error since all subscriptions were removed
unsubscribeMockHandlerTwo();
log.info('goodbye world!');
expect(stderrSpy.mock.calls).toMatchSnapshot('stderr');
stderrSpy.mockRestore();
});
});
