text: const test = require("ava")
  const proxyquire = require("proxyquire")
  const stripe = require("./_stripe.stub") // stubbed
  
  const { getDefaultCustomerCard } = proxyquire("../index.js", {
    stripe
  })("dummy_stripe_token")
  
  test("Should be a function.", (t) => {
    t.is(typeof getDefaultCustomerCard, "function")
  })
  
  test("Should return a customer's default card'", async (t) => {
    t.is(await getDefaultCustomerCard("cus_ClfSlfACLDjib2"), "card_1CLrcwIacGIwwFOIAfrKTKHu")
  })
  