import assert from 'node:assert/strict';
import { readdirSync } from 'node:fs';
import { describe, it } from 'node:test';
import {
ErrorCode,
getSuggestion,
isNodeError,
McpError,
} from '../../lib/errors.js';
// ─── isNodeError ────────────────────────────────────────────────────────────
describe('isNodeError', () => {
it('returns true for system errors with a string code', () => {
let err: NodeJS.ErrnoException | undefined;
try {
readdirSync('/nonexistent-path-that-cannot-exist-' + Date.now());
} catch (e: unknown) {
err = e as NodeJS.ErrnoException;
}
assert.ok(err !== undefined, 'Should have thrown');
assert.equal(isNodeError(err), true);
});
it('returns false for plain Error with no code', () => {
assert.equal(isNodeError(new Error('plain')), false);
});
it('returns false for plain Error with numeric code', () => {
const e = Object.assign(new Error('numeric'), { code: 42 });
assert.equal(isNodeError(e), false);
});
it('returns false for non-Error primitives', () => {
assert.equal(isNodeError('not an error'), false);
assert.equal(isNodeError(null), false);
assert.equal(isNodeError(undefined), false);
assert.equal(isNodeError({}), false);
});
});
// ─── McpError ───────────────────────────────────────────────────────────────
describe('McpError', () => {
it('stores code, message, and is instanceof Error', () => {
const err = new McpError(ErrorCode.E_NOT_FOUND, 'file not found');
assert.equal(err.code, ErrorCode.E_NOT_FOUND);
assert.equal(err.message, 'file not found');
assert.ok(err instanceof Error);
});
it('has name "McpError"', () => {
const err = new McpError(ErrorCode.E_PERMISSION_DENIED, 'no access');
assert.equal(err.name, 'McpError');
});
it('stores optional path', () => {
const err = new McpError(ErrorCode.E_NOT_FOUND, 'msg', '/some/path');
assert.equal(err.path, '/some/path');
});
it('stores no path when not provided', () => {
const err = new McpError(ErrorCode.E_NOT_FOUND, 'msg');
assert.equal(err.path, undefined);
});
});
// ─── getSuggestion ──────────────────────────────────────────────────────────
describe('getSuggestion', () => {
it('returns a non-empty string for every ErrorCode value', () => {
for (const code of Object.values(ErrorCode)) {
const suggestion = getSuggestion(code);
assert.equal(typeof suggestion, 'string');
assert.ok(
suggestion.length > 0,
`Expected non-empty suggestion for ${code}`
);
}
});
});
