/**
* Unit tests for JSON-RPC parser and line buffer
*/
import { describe, it, expect } from 'vitest';
import { parseJsonRpcLine, createLineBuffer } from '../parser';
describe('parseJsonRpcLine', () => {
it('valid JSON-RPC returns message', () => {
const line = '{"jsonrpc":"2.0","id":1,"method":"tools/call","params":{}}';
const result = parseJsonRpcLine(line);
expect(result).not.toBeNull();
expect(result?.jsonrpc).toBe('2.0');
expect(result?.id).toBe(1);
expect(result?.method).toBe('tools/call');
expect(result?.params).toEqual({});
});
it('invalid JSON returns null', () => {
const line = '{"jsonrpc":"2.0",invalid}';
const result = parseJsonRpcLine(line);
expect(result).toBeNull();
});
it('non-2.0 jsonrpc field returns null', () => {
const line = '{"jsonrpc":"1.0","id":1,"method":"test"}';
const result = parseJsonRpcLine(line);
expect(result).toBeNull();
});
it('missing jsonrpc field returns null', () => {
const line = '{"id":1,"method":"test"}';
const result = parseJsonRpcLine(line);
expect(result).toBeNull();
});
it('empty string returns null', () => {
const result = parseJsonRpcLine('');
expect(result).toBeNull();
});
it('whitespace-only string returns null', () => {
const result = parseJsonRpcLine(' \n\t ');
expect(result).toBeNull();
});
it('parses response message (no method)', () => {
const line = '{"jsonrpc":"2.0","id":1,"result":{"success":true}}';
const result = parseJsonRpcLine(line);
expect(result).not.toBeNull();
expect(result?.jsonrpc).toBe('2.0');
expect(result?.id).toBe(1);
expect(result?.result).toEqual({ success: true });
expect(result?.method).toBeUndefined();
});
it('parses error response', () => {
const line = '{"jsonrpc":"2.0","id":1,"error":{"code":-32601,"message":"Method not found"}}';
const result = parseJsonRpcLine(line);
expect(result).not.toBeNull();
expect(result?.jsonrpc).toBe('2.0');
expect(result?.error?.code).toBe(-32601);
expect(result?.error?.message).toBe('Method not found');
});
});
describe('createLineBuffer', () => {
it('complete lines emitted immediately', () => {
const lines: string[] = [];
const buffer = createLineBuffer((line) => lines.push(line));
buffer.push('{"jsonrpc":"2.0","id":1}\n');
expect(lines).toEqual(['{"jsonrpc":"2.0","id":1}']);
});
it('partial lines buffered until newline', () => {
const lines: string[] = [];
const buffer = createLineBuffer((line) => lines.push(line));
buffer.push('{"jsonrpc":"2.0",');
expect(lines).toEqual([]);
buffer.push('"id":1}\n');
expect(lines).toEqual(['{"jsonrpc":"2.0","id":1}']);
});
it('multiple lines in one chunk', () => {
const lines: string[] = [];
const buffer = createLineBuffer((line) => lines.push(line));
buffer.push('{"jsonrpc":"2.0","id":1}\n{"jsonrpc":"2.0","id":2}\n');
expect(lines).toEqual([
'{"jsonrpc":"2.0","id":1}',
'{"jsonrpc":"2.0","id":2}'
]);
});
it('flush emits remaining buffer content', () => {
const lines: string[] = [];
const buffer = createLineBuffer((line) => lines.push(line));
buffer.push('{"jsonrpc":"2.0","id":1}\n');
buffer.push('{"jsonrpc":"2.0","id":2}');
expect(lines).toEqual(['{"jsonrpc":"2.0","id":1}']);
buffer.flush();
expect(lines).toEqual([
'{"jsonrpc":"2.0","id":1}',
'{"jsonrpc":"2.0","id":2}'
]);
});
it('flush does not emit empty buffer', () => {
const lines: string[] = [];
const buffer = createLineBuffer((line) => lines.push(line));
buffer.push('{"jsonrpc":"2.0","id":1}\n');
buffer.flush();
expect(lines).toEqual(['{"jsonrpc":"2.0","id":1}']);
});
it('flush does not emit whitespace-only buffer', () => {
const lines: string[] = [];
const buffer = createLineBuffer((line) => lines.push(line));
buffer.push('{"jsonrpc":"2.0","id":1}\n \n');
buffer.flush();
expect(lines).toEqual(['{"jsonrpc":"2.0","id":1}', ' ']);
});
it('handles mixed complete and incomplete lines', () => {
const lines: string[] = [];
const buffer = createLineBuffer((line) => lines.push(line));
buffer.push('line1\nline2\npartial');
expect(lines).toEqual(['line1', 'line2']);
buffer.push('_end\nline3\n');
expect(lines).toEqual(['line1', 'line2', 'partial_end', 'line3']);
});
it('handles empty lines in chunk', () => {
const lines: string[] = [];
const buffer = createLineBuffer((line) => lines.push(line));
buffer.push('line1\n\nline2\n');
// Empty lines are filtered by the buffer implementation
expect(lines).toEqual(['line1', 'line2']);
});
it('handles chunk ending with newline', () => {
const lines: string[] = [];
const buffer = createLineBuffer((line) => lines.push(line));
buffer.push('line1\nline2\n');
expect(lines).toEqual(['line1', 'line2']);
buffer.push('line3\n');
expect(lines).toEqual(['line1', 'line2', 'line3']);
});
});
