TODO-3 (commit 8ffe3616) added an optional 'logger' callback to MCPConfig
plus an exported McpLogger interface so consumers can route MCP output
to pino, Fastify request.log, structlog, etc., instead of the default
global console. The package had zero unit tests; the new interface
relied on type-system validation alone.
This commit adds packages/mcp-client/src/logger.test.ts (4 tests) to
cover the public contract introduced by TODO-3:
1. defaults to global console when no logger is provided
\u2014 verifies the '?? console' fallback in the constructor.
2. injected logger receives no spurious calls on early-return paths
\u2014 disconnect() when not connected is a no-op; logger must
not be invoked.
3. structural-typing acceptance test \u2014 a pino-shaped logger
(no-op methods) must construct cleanly. Guards the McpLogger
interface from accidental narrowing during future refactors.
4. variadic-args contract \u2014 McpLogger.info('msg', {ctx}, 42)
accepts trailing structured args; matches console + pino + Fastify.
The deeper integration paths (connect / callTool / readResource) spawn
StdioClientTransport subprocesses and aren't safely runnable in a unit
context; they're covered indirectly by consumers (admin-dashboard
uses the same client and has integration tests).
Result: mcp-client moves from 0 tests to 4 tests passing.
092af2dc9b