Add native LLM core foundation (#24712)

packages/llm/test/endpoint.test.ts

@@ -0,0 +1,57 @@
+import { describe, expect, test } from "bun:test"
+import { LLM } from "../src"
+import { Endpoint } from "../src/route"
+
+const request = (
+  input: {
+    readonly baseURL: string
+    readonly queryParams?: Record<string, string>
+  },
+) =>
+  LLM.request({
+    model: LLM.model({
+      id: "model-1",
+      provider: "test",
+      route: "test-route",
+      baseURL: input.baseURL,
+      queryParams: input.queryParams,
+    }),
+    prompt: "hello",
+  })
+
+describe("Endpoint", () => {
+  test("appends a static path to the model's baseURL", () => {
+    const url = Endpoint.render(Endpoint.path("/chat"), {
+      request: request({ baseURL: "https://api.example.test/v1/" }),
+      body: {},
+    })
+
+    expect(url.toString()).toBe("https://api.example.test/v1/chat")
+  })
+
+  test("model query params are appended to the rendered URL", () => {
+    const url = Endpoint.render(Endpoint.path("/chat?alt=sse"), {
+      request: request({
+        baseURL: "https://custom.example.test/root/",
+        queryParams: { "api-version": "2026-01-01", alt: "json" },
+      }),
+      body: {},
+    })
+
+    expect(url.toString()).toBe("https://custom.example.test/root/chat?alt=json&api-version=2026-01-01")
+  })
+
+  test("path may be a function of the validated body", () => {
+    const url = Endpoint.render(
+      Endpoint.path<{ readonly modelId: string }>(({ body }) => `/model/${encodeURIComponent(body.modelId)}/converse-stream`),
+      {
+        request: request({ baseURL: "https://bedrock-runtime.us-east-1.amazonaws.com" }),
+        body: { modelId: "us.amazon.nova-micro-v1:0" },
+      },
+    )
+
+    expect(url.toString()).toBe(
+      "https://bedrock-runtime.us-east-1.amazonaws.com/model/us.amazon.nova-micro-v1%3A0/converse-stream",
+    )
+  })
+})