Using the ctx · 60 / 69

Handle GraphQL response envelopes

YOUR TASK

Make this happen

3 steps

Check the host flag and response type, reject nonempty errors, then return data. On the platform, operations still run with the caller’s authorization. A passing mock test does not prove that a real account has permission or that a business query matches the live schema.
Read the cases in lesson.test.lua, then choose Check solution to see what needs to change.
Update subject.lua until every test passes. Keep the supplied tests unchanged.

Read the starter and tests

subject.lua

exports.read = function(document: string)
  local ok, result = ctx.graphql.query(document, {})
  return result
end

lesson.test.lua

local t = require("test")
local subject = require("cococo.subject")

local document = "query AcademyContext { __typename }"
t.it("unwraps successful data and forwards the document", function()
  t.mock
    .host("ctx.graphql.query")
    :returns(true, { data = { __typename = "Query" } })
  local s = subject.load()
  t.expect(s.read(document)):deep_eq({ __typename = "Query" })
  t.expect(t.mock.spy("ctx.graphql.query")):called_with(document, {})
end)
t.it("handles host failure", function()
  t.mock.host("ctx.graphql.query"):returns(false, "unavailable")
  local s = subject.load()
  t.expect(s.read(document)):is_nil()
end)
t.it("rejects a response containing GraphQL errors", function()
  t.mock
    .host("ctx.graphql.query")
    :returns(true, { errors = { { message = "denied" } } })
  local s = subject.load()
  t.expect(s.read(document)):is_nil()
end)