opencode/packages/codemode/test/enumeration.test.ts

import { describe, expect, test } from "bun:test"
import { Effect, Schema } from "effect"
import { CodeMode, Tool } from "../src/index.js"

// Key enumeration: Object.keys and for...in share one surface over plain objects, arrays
// (index strings), and tool references (namespace/tool names from the host tool tree), so a
// model can discover what it may call instead of guessing names from the instructions. The
// motivating transcript: `Object.keys(tools)` failed with the generic plain-objects-only
// message and `for (const key in tools)` was unsupported syntax, forcing blind guesses.

const echo = (description: string) =>
  Tool.make({
    description,
    input: Schema.Struct({ value: Schema.String }),
    output: Schema.String,
    run: ({ value }) => Effect.succeed(value),
  })

const tools = {
  github: { list_issues: echo("List issues"), get_issue: echo("Get one issue") },
  memory: { search: echo("Search memory") },
  playwright: { navigate: echo("Navigate somewhere") },
}

const run = (code: string) => Effect.runPromise(CodeMode.execute({ tools, code }))
const value = async (code: string) => {
  const result = await run(code)
  if (!result.ok) throw new Error(`expected success, got ${result.error.kind}: ${result.error.message}`)
  return result.value
}
const error = async (code: string) => {
  const result = await run(code)
  if (result.ok) throw new Error(`expected failure, got value ${JSON.stringify(result.value)}`)
  return result.error
}

describe("Object.keys over tool references", () => {
  test("enumerates top-level namespaces (the transcript program)", async () => {
    expect(await value(`
      const namespaces = Object.keys(tools)
      return { namespaces, count: namespaces.length }
    `)).toEqual({ namespaces: ["github", "memory", "playwright"], count: 3 })
  })

  test("enumerates tool names at a nested namespace", async () => {
    expect(await value(`return Object.keys(tools.github)`)).toEqual(["list_issues", "get_issue"])
  })

  test("a callable tool is a leaf and enumerates as []", async () => {
    expect(await value(`return Object.keys(tools.github.list_issues)`)).toEqual([])
  })

  test("the virtual discovery namespace enumerates its callable surface", async () => {
    expect(await value(`return Object.keys(tools.$codemode)`)).toEqual(["search"])
  })

  test("an unknown namespace is an UnknownTool error pointing at the discovery idioms", async () => {
    const failure = await error(`return Object.keys(tools.nonexistent)`)
    expect(failure.kind).toBe("UnknownTool")
    expect(failure.message).toContain("Unknown tool namespace 'nonexistent'")
    expect(failure.suggestions?.join(" ")).toContain("Object.keys(tools)")
  })

  test("Object.values/entries on a tool reference explain the working idioms", async () => {
    for (const method of ["values", "entries"] as const) {
      const failure = await error(`return Object.${method}(tools)`)
      expect(failure.kind).toBe("InvalidDataValue")
      expect(failure.message).toContain(
        `Object.${method}(...) cannot read tool references: they are not plain data. Use Object.keys(tools) for names, or tools.$codemode.search({ query }) for signatures.`,
      )
    }
    const nested = await error(`return Object.entries(tools.github)`)
    expect(nested.message).toContain("Use Object.keys(tools) for names")
  })
})

describe("Object.keys over arrays", () => {
  test("returns index strings, like JS", async () => {
    expect(await value(`return Object.keys(["a", "b", "c"])`)).toEqual(["0", "1", "2"])
    expect(await value(`return Object.keys([])`)).toEqual([])
  })

  test("objects keep their own enumerable keys", async () => {
    expect(await value(`return Object.keys({ a: 1, b: 2 })`)).toEqual(["a", "b"])
  })

  test("non-object inputs still fail clearly", async () => {
    const failure = await error(`return Object.keys("nope")`)
    expect(failure.message).toContain("Object.keys expects a data object or array")
  })
})

describe("for...in", () => {
  test("iterates own enumerable keys of a plain object with break/continue", async () => {
    expect(await value(`
      const seen = []
      for (const key in { a: 1, b: 2, c: 3, d: 4 }) {
        if (key === "b") continue
        if (key === "d") break
        seen.push(key)
      }
      return seen
    `)).toEqual(["a", "c"])
  })

  test("iterates index strings over arrays", async () => {
    expect(await value(`
      const indexes = []
      for (const i in ["x", "y", "z"]) {
        if (i === "2") break
        indexes.push(i)
      }
      return indexes
    `)).toEqual(["0", "1"])
  })

  test("supports let declarations and bare identifiers", async () => {
    expect(await value(`
      let last = ""
      for (let key in { a: 1, b: 2 }) last = key
      return last
    `)).toBe("b")
    expect(await value(`
      let key = "before"
      for (key in { only: 1 }) {}
      return key
    `)).toBe("only")
  })

  test("enumerates namespaces and tools from the host tool tree", async () => {
    expect(await value(`
      const names = []
      for (const ns in tools) {
        for (const name in tools[ns]) names.push(ns + "." + name)
      }
      return names
    `)).toEqual(["github.list_issues", "github.get_issue", "memory.search", "playwright.navigate"])
  })

  test("unsupported values fail with a hint at for...of and Object.keys", async () => {
    for (const expression of [`"text"`, "new Map([[1, 2]])", "new Set([1])", "42", "null"]) {
      const failure = await error(`for (const key in ${expression}) {}; return "no"`)
      expect(failure.message).toContain("for...in requires a plain object, array, or tools reference")
      expect(failure.message).toContain("Use for...of for arrays/strings/Maps/Sets, or Object.keys(value)")
    }
  })
})