feat(subagent): add Claude Code provider

packages/subagent/subagent-claude-code/tests/messages-fixture.ts

@@ -0,0 +1,163 @@
+import { createServer, type IncomingHttpHeaders, type ServerResponse } from 'node:http'
+
+/** One deterministic response emitted by the package-private Messages server. */
+export type MessagesBehavior =
+  | { readonly kind: 'complete'; readonly text: string }
+  | { readonly kind: 'hold' }
+
+/** One recorded Anthropic Messages request. */
+interface RecordedMessagesRequest {
+  readonly method: string
+  readonly path: string
+  readonly headers: IncomingHttpHeaders
+  readonly body: Record<string, unknown>
+}
+
+/** Running package-private Anthropic Messages fixture. */
+export interface MessagesFixture {
+  readonly baseUrl: string
+  readonly requests: RecordedMessagesRequest[]
+  readonly requestStarted: Promise<void>
+  close(): Promise<void>
+}
+
+function event(
+  response: ServerResponse,
+  type: string,
+  payload: Record<string, unknown>,
+): void {
+  response.write(`event: ${type}\ndata: ${JSON.stringify(payload)}\n\n`)
+}
+
+function complete(
+  response: ServerResponse,
+  body: Record<string, unknown>,
+  text: string,
+): void {
+  const model = typeof body.model === 'string' ? body.model : 'fixture-model'
+  response.writeHead(200, {
+    'content-type': 'text/event-stream',
+    'cache-control': 'no-cache',
+    connection: 'keep-alive',
+  })
+  event(response, 'message_start', {
+    type: 'message_start',
+    message: {
+      id: 'msg_dsh_fixture',
+      type: 'message',
+      role: 'assistant',
+      model,
+      content: [],
+      stop_reason: null,
+      stop_sequence: null,
+      usage: {
+        input_tokens: 7,
+        output_tokens: 0,
+        cache_creation_input_tokens: 0,
+        cache_read_input_tokens: 0,
+      },
+    },
+  })
+  event(response, 'content_block_start', {
+    type: 'content_block_start',
+    index: 0,
+    content_block: { type: 'text', text: '' },
+  })
+  event(response, 'content_block_delta', {
+    type: 'content_block_delta',
+    index: 0,
+    delta: { type: 'text_delta', text },
+  })
+  event(response, 'content_block_stop', {
+    type: 'content_block_stop',
+    index: 0,
+  })
+  event(response, 'message_delta', {
+    type: 'message_delta',
+    delta: { stop_reason: 'end_turn', stop_sequence: null },
+    usage: { output_tokens: 1 },
+  })
+  event(response, 'message_stop', { type: 'message_stop' })
+  response.end()
+}
+
+/**
+ * Start a loopback-only Anthropic Messages SSE fixture.
+ * @param script - one behavior per Messages request.
+ * @returns the bound server and its recorded requests.
+ */
+export async function startMessagesFixture(
+  script: readonly MessagesBehavior[],
+): Promise<MessagesFixture> {
+  const requests: RecordedMessagesRequest[] = []
+  let requestStartedResolve!: () => void
+  const requestStarted = new Promise<void>((resolve) => {
+    requestStartedResolve = resolve
+  })
+  let behaviorIndex = 0
+  const server = createServer((request, response) => {
+    const chunks: Buffer[] = []
+    request.on('data', (chunk: Buffer) => { chunks.push(chunk) })
+    request.on('end', () => {
+      const path = request.url ?? ''
+      if (!path.startsWith('/v1/messages')) {
+        response.writeHead(404, { 'content-type': 'application/json' })
+        response.end(JSON.stringify({
+          type: 'error',
+          error: { type: 'not_found_error', message: `unexpected path ${path}` },
+        }))
+        return
+      }
+      const text = Buffer.concat(chunks).toString('utf8')
+      const body = JSON.parse(text) as Record<string, unknown>
+      requests.push({
+        method: request.method ?? '',
+        path,
+        headers: request.headers,
+        body,
+      })
+      requestStartedResolve()
+      const behavior = script[behaviorIndex++]
+      if (behavior === undefined) {
+        response.writeHead(500, { 'content-type': 'application/json' })
+        response.end(JSON.stringify({
+          type: 'error',
+          error: {
+            type: 'api_error',
+            message: 'Messages fixture script was exhausted',
+          },
+        }))
+        return
+      }
+      if (behavior.kind === 'complete') {
+        complete(response, body, behavior.text)
+      }
+      // A hold deliberately leaves the response pending until client abort.
+    })
+  })
+  await new Promise<void>((resolve, reject) => {
+    server.once('error', reject)
+    server.listen(0, '127.0.0.1', () => {
+      server.off('error', reject)
+      resolve()
+    })
+  })
+  const address = server.address()
+  if (address === null || typeof address === 'string') {
+    throw new Error('Messages fixture did not bind a TCP port')
+  }
+  return {
+    baseUrl: `http://127.0.0.1:${address.port}`,
+    requests,
+    requestStarted,
+    async close(): Promise<void> {
+      server.closeAllConnections()
+      await new Promise<void>((resolve, reject) => {
+        server.close((error) => {
+          if (error !== undefined) reject(error)
+          else resolve()
+        })
+      })
+    },
+  }
+}