uniswap-interface-uncensored/cypress/e2e/permit2.test.ts

import { MaxUint160, MaxUint256 } from '@uniswap/permit2-sdk'

import { DAI, USDC_MAINNET } from '../../src/constants/tokens'
import { getTestSelector } from '../utils'

/** Initiates a swap. */
function initiateSwap() {
  // The swap button is re-rendered once enable, so we must wait until the original button is not disabled to re-select the appropriate button.
  cy.get('#swap-button').should('not.be.disabled')
  // Completes the swap.
  cy.get('#swap-button').click()
  cy.get(getTestSelector('confirm-swap-button')).click()
}

describe('Permit2', () => {
  // The same tokens & swap-amount combination is used for all permit2 tests.
  const INPUT_TOKEN = DAI
  const OUTPUT_TOKEN = USDC_MAINNET
  const TEST_BALANCE_INCREMENT = 0.01

  beforeEach(() => {
    // Sets up a swap between INPUT_TOKEN and OUTPUT_TOKEN.
    cy.visit(`/swap/?inputCurrency=${INPUT_TOKEN.address}&outputCurrency=${OUTPUT_TOKEN.address}`, {
      ethereum: 'hardhat',
    })
    cy.get('#swap-currency-input .token-amount-input').type(TEST_BALANCE_INCREMENT.toString())
  })

  /** Asserts permit2 has a max approval for spend of the input token on-chain. */
  function expectTokenAllowanceForPermit2ToBeMax() {
    // check token approval
    return cy
      .hardhat()
      .then(({ approval, wallet }) => approval.getTokenAllowanceForPermit2({ owner: wallet, token: INPUT_TOKEN }))
      .should('deep.equal', MaxUint256)
  }

  /** Asserts the universal router has a max permit2 approval for spend of the input token on-chain. */
  function expectPermit2AllowanceForUniversalRouterToBeMax(approvalTime: number) {
    return cy
      .hardhat()
      .then((hardhat) => hardhat.approval.getPermit2Allowance({ owner: hardhat.wallet, token: INPUT_TOKEN }))
      .then((allowance) => {
        cy.wrap(MaxUint160.eq(allowance.amount)).should('eq', true)
        // Asserts that the on-chain expiration is in 30 days, within a tolerance of 40 seconds.
        const expected = Math.floor((approvalTime + 2_592_000_000) / 1000)
        cy.wrap(allowance.expiration).should('be.closeTo', expected, 40)
      })
  }

  it('swaps when user has already approved token and permit2', () => {
    cy.hardhat().then(({ approval, wallet }) => {
      approval.setTokenAllowanceForPermit2({ owner: wallet, token: INPUT_TOKEN })
      approval.setPermit2Allowance({ owner: wallet, token: INPUT_TOKEN })
    })
    initiateSwap()
    cy.get(getTestSelector('confirmation-close-icon')).click()
    // Verifies that there is a successful swap notification.
    cy.contains('Swapped').should('exist')
  })

  it('swaps after completing full permit2 approval process', () => {
    cy.hardhat().then(({ provider }) => {
      cy.spy(provider, 'send').as('permitApprovalSpy')
    })
    initiateSwap()
    cy.contains('Enable spending limits for DAI on Uniswap').should('exist')
    cy.contains('Approved').should('exist')

    cy.contains('Allow DAI to be used for swapping').should('exist')
    cy.contains('Confirm Swap').should('exist')

    cy.then(() => {
      const approvalTime = Date.now()

      cy.contains('Swapped').should('exist')

      expectTokenAllowanceForPermit2ToBeMax()
      expectPermit2AllowanceForUniversalRouterToBeMax(approvalTime)
      cy.get('@permitApprovalSpy').should('have.been.calledWith', 'eth_signTypedData_v4')
    })
  })

  it('swaps after handling user rejection of both approval and signature', () => {
    const USER_REJECTION = { code: 4001 }
    cy.hardhat().then((hardhat) => {
      const tokenApprovalStub = cy.stub(hardhat.wallet, 'sendTransaction')
      tokenApprovalStub.rejects(USER_REJECTION) // reject token approval
      const permitApprovalStub = cy.stub(hardhat.provider, 'send')
      permitApprovalStub.withArgs('eth_signTypedData_v4').rejects(USER_REJECTION) // reject permit approval
      permitApprovalStub.callThrough() // allows non-eth_signTypedData_v4 send calls to return non-stubbed values

      initiateSwap()

      // tokenApprovalStub should reject here, and the modal should revert to the review state.
      cy.contains('Review swap').should('be.visible')

      cy.then(() => {
        // The user is now allowing approval, but the permit2 signature will be rejected by the user (permitApprovalStub).
        tokenApprovalStub.restore() // allow token approval
      })

      cy.get(getTestSelector('confirm-swap-button')).click()
      cy.contains('Enable spending limits for DAI on Uniswap').should('exist')
      cy.contains('Approved').should('exist')

      // permitApprovalStub should reject here, and the modal should revert to the review state.
      cy.contains('Review swap')
        .should('be.visible')
        .then(() => {
          permitApprovalStub.restore() // allow permit approval
        })

      cy.get(getTestSelector('confirm-swap-button')).click()

      // The swap should now be able to proceed, as the permit2 signature will be accepted by the user.
      const approvalTime = Date.now()

      cy.contains('Confirm Swap').should('exist')
      cy.contains('Swapped').should('exist')

      expectTokenAllowanceForPermit2ToBeMax()
      expectPermit2AllowanceForUniversalRouterToBeMax(approvalTime)
    })
  })

  it('swaps with existing token approval and missing permit approval', () => {
    cy.hardhat().then(({ approval, wallet, provider }) => {
      approval.setTokenAllowanceForPermit2({ owner: wallet, token: INPUT_TOKEN })
      cy.spy(provider, 'send').as('permitApprovalSpy')
    })
    cy.then(() => initiateSwap())
    cy.then(() => {
      const approvalTime = Date.now()

      cy.contains('Confirm Swap').should('exist')
      cy.contains('Swapped').should('exist')

      expectPermit2AllowanceForUniversalRouterToBeMax(approvalTime)
      cy.get('@permitApprovalSpy').should('have.been.calledWith', 'eth_signTypedData_v4')
    })
  })

  it('swaps with existing permit approval and missing token approval', () => {
    cy.hardhat().then(({ approval, wallet }) => approval.setPermit2Allowance({ owner: wallet, token: INPUT_TOKEN }))
    cy.then(() => {
      initiateSwap()
    })
    cy.then(() => {
      const approvalTime = Date.now()

      cy.contains('Confirm Swap').should('exist')
      cy.contains('Swapped').should('exist')

      expectPermit2AllowanceForUniversalRouterToBeMax(approvalTime)
    })
  })

  it('prompts signature when existing permit approval is expired', () => {
    const expiredAllowance = { expiration: Math.floor((Date.now() - 1) / 1000) }

    cy.hardhat().then(({ approval, wallet, provider }) => {
      approval.setTokenAllowanceForPermit2({ owner: wallet, token: INPUT_TOKEN })
      approval.setPermit2Allowance({ owner: wallet, token: INPUT_TOKEN }, expiredAllowance)
      cy.spy(provider, 'send').as('permitApprovalSpy')
    })
    cy.then(() => {
      initiateSwap()
    })
    cy.then(() => {
      const approvalTime = Date.now()

      cy.contains('Confirm Swap').should('exist')
      cy.contains('Swapped').should('exist')

      expectPermit2AllowanceForUniversalRouterToBeMax(approvalTime)
      cy.get('@permitApprovalSpy').should('have.been.calledWith', 'eth_signTypedData_v4')
    })
  })

  it('prompts signature when existing permit approval amount is too low', () => {
    const smallAllowance = { amount: 1 }

    cy.hardhat().then(({ approval, wallet, provider }) => {
      approval.setTokenAllowanceForPermit2({ owner: wallet, token: INPUT_TOKEN })
      approval.setPermit2Allowance({ owner: wallet, token: INPUT_TOKEN }, smallAllowance)
      cy.spy(provider, 'send').as('permitApprovalSpy')
      initiateSwap()
      const approvalTime = Date.now()

      cy.contains('Confirm Swap').should('exist')
      cy.contains('Swapped').should('exist')

      expectPermit2AllowanceForUniversalRouterToBeMax(approvalTime)
      cy.get('@permitApprovalSpy').should('have.been.calledWith', 'eth_signTypedData_v4')
    })
  })

  it('prompts token approval when existing approval amount is too low', () => {
    cy.hardhat()
      .then(({ approval, wallet }) => {
        approval.setPermit2Allowance({ owner: wallet, token: INPUT_TOKEN })
        approval.setTokenAllowanceForPermit2({ owner: wallet, token: INPUT_TOKEN }, 1)
      })
      .then(() => {
        initiateSwap()
        const approvalTime = Date.now()
        cy.contains('Enable spending limits for DAI on Uniswap').should('exist')

        cy.contains('Confirm Swap').should('exist')
        cy.contains('Swapped').should('exist')

        expectPermit2AllowanceForUniversalRouterToBeMax(approvalTime)
      })
  })
})