test(e2e): reset hardhat between tests (#6487)

cypress/e2e/swap.test.ts

@@ -84,10 +84,9 @@ describe('Swap', () => {
       const DEADLINE_MINUTES = 1
       const TEN_MINUTES_MS = 1000 * 60 * DEADLINE_MINUTES * 10
       cy.visit('/swap', { ethereum: 'hardhat' })
-        .hardhat()
+        .hardhat({ automine: false })
         .then((hardhat) => {
-          cy.then(() => hardhat.setAutomine(false))
-            .then(() => hardhat.getBalance(hardhat.wallet.address, USDC_MAINNET))
+          cy.then(() => hardhat.getBalance(hardhat.wallet.address, USDC_MAINNET))
             .then((balance) => Number(balance.toFixed(1)))
             .then((initialBalance) => {
               // Input swap info.
@@ -209,7 +208,6 @@ describe('Swap', () => {
             cy.get('#confirm-swap-or-send').click()
             cy.get(getTestSelector('dismiss-tx-confirmation')).click()
 
-            cy.then(() => hardhat.provider.send('hardhat_mine', ['0x1', '0xc'])).then(() => {
             // ui check
             cy.get('#swap-currency-output [data-testid="balance-text"]').should(
               'have.text',
@@ -224,7 +222,6 @@ describe('Swap', () => {
       })
     })
   })
-  })
 
   it('should be able to wrap ETH', () => {
     const BALANCE_INCREMENT = 1
@@ -417,11 +414,9 @@ describe('Swap', () => {
 
   it('should render an error for slippage failure', () => {
     cy.visit('/swap', { ethereum: 'hardhat' })
-      .hardhat()
+      .hardhat({ automine: false })
       .then((hardhat) => {
-        cy.then(() => hardhat.setAutomine(false))
-          .then(() => hardhat.provider.getBalance(hardhat.wallet.address))
-          .then((initialBalance) => {
+        cy.then(() => hardhat.provider.getBalance(hardhat.wallet.address)).then((initialBalance) => {
           // Gas estimation fails for this transaction (that would normally fail), so we stub it.
           const send = cy.stub(hardhat.provider, 'send')
           send.withArgs('eth_estimateGas').resolves(BigNumber.from(2_000_000))
@@ -478,7 +473,6 @@ describe('Swap', () => {
             })
           })
         })
-          .then(() => hardhat.setAutomine(true))
       })
   })
 })

cypress/support/e2e.ts

@@ -89,8 +89,9 @@ Cypress.Commands.overwrite(
 )
 
 beforeEach(() => {
+  cy
     // Many API calls enforce that requests come from our app, so we must mock Origin and Referer.
-  cy.intercept('*', (req) => {
+    .intercept('*', (req) => {
       req.headers['referer'] = 'https://app.uniswap.org'
       req.headers['origin'] = 'https://app.uniswap.org'
     })
@@ -114,6 +115,10 @@ beforeEach(() => {
         })
       )
     })
+    // Reset hardhat between tests to ensure isolation.
+    // This resets the fork, as well as options like automine.
+    .hardhat()
+    .then((hardhat) => hardhat.reset())
 })
 
 Cypress.on('uncaught:exception', () => {

hardhat.config.js

@@ -22,8 +22,8 @@ module.exports = {
         count: 1,
       },
       mining: {
-        auto: true,
-        interval: 0,
+        auto: true, // automine to make tests easier to write.
+        interval: 0, // do not interval mine so that tests remain deterministic
       },
     },
   },

package.json

@@ -102,7 +102,7 @@
     "@vanilla-extract/webpack-plugin": "^2.1.11",
     "babel-plugin-istanbul": "^6.1.1",
     "cypress": "10.3.1",
-    "cypress-hardhat": "^2.2.0",
+    "cypress-hardhat": "^2.3.0",
     "env-cmd": "^10.1.0",
     "eslint": "^7.11.0",
     "eslint-plugin-import": "^2.27",

yarn.lock

@@ -9046,10 +9046,10 @@ cyclist@^1.0.1:
   resolved "https://registry.yarnpkg.com/cyclist/-/cyclist-1.0.1.tgz#596e9698fd0c80e12038c2b82d6eb1b35b6224d9"
   integrity sha1-WW6WmP0MgOEgOMK4LW6xs1tiJNk=
 
-cypress-hardhat@^2.2.0:
-  version "2.2.0"
-  resolved "https://registry.yarnpkg.com/cypress-hardhat/-/cypress-hardhat-2.2.0.tgz#4e1c0f16f0c915dda54ddeccbf5dea19f80eed2f"
-  integrity sha512-Jtzd49vvyWSshR43w18WJ4b/40EhSItTTl82QYBNqiSPPrC/yj0derJHZyqMqq2LZvrsfmiY92fIBDgvxUCxZQ==
+cypress-hardhat@^2.3.0:
+  version "2.3.0"
+  resolved "https://registry.yarnpkg.com/cypress-hardhat/-/cypress-hardhat-2.3.0.tgz#646b35d57490d060e3fd4441e76e4d91b4ff4ec7"
+  integrity sha512-Sj437lFrUZ9UJGXS5a+DLQPBoyaWUxJafEiydNqKKpViKswBiylHD3ZJu2mrtQ/fhp7lgOPpMP72IQX4Ncwzdg==
   dependencies:
     "@uniswap/permit2-sdk" "^1.2.0"
     "@uniswap/sdk-core" "^3.0.1"