🪢 Chaining matchers (#717)

TrueFiEng · May 4, 2022 · 587ff49 · 587ff49
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diff --git a/.changeset/big-shrimps-rule.md b/.changeset/big-shrimps-rule.md
@@ -0,0 +1,5 @@
+---
+"@ethereum-waffle/chai": patch
+---
+
+Allow chaining matchers
diff --git a/docs/source/configuration.rst b/docs/source/configuration.rst
@@ -49,6 +49,7 @@ Afterwards update your :code:`package.json` build script:
       }
 
   .. group-tab:: Waffle 2.5.0
+
     .. code-block:: json
 
       {

diff --git a/docs/source/migration-guides.rst b/docs/source/migration-guides.rst
@@ -436,10 +436,10 @@ In the new Ganache, you should not override the wallet config, otherwise you mig
     }
   })
 
-Chaining :code:`emit` matchers
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Chaining matchers
+~~~~~~~~~~~~~~~~~
 
-Now when testing events on a smart contract you can conveniently chain :code:`emit` matchers.
+Now when testing events on a smart contract you can conveniently chain matchers. It can be especially useful when testing events.
 
 .. code-block:: ts
   
@@ -454,3 +454,39 @@ Now when testing events on a smart contract you can conveniently chain :code:`em
           'Two'
         )
         .to.not.emit(contract, 'Three');
+
+:code:`changeEtherBalance`, :code:`changeEtherBalances`, :code:`changeTokenbalance` and :code:`changeTokenBalances` matchers also support chaining:
+
+.. code-block:: ts
+
+  await token.approve(complex.address, 100);
+  const tx = await complex.doEverything(receiver.address, 100, {value: 200});
+  await expect(tx)
+    .to.changeTokenBalances(token, [sender, receiver], [-100, 100])
+    .and.to.changeEtherBalances([sender, receiver], [-200, 200])
+    .and.to.emit(complex, 'TransferredEther').withArgs(200)
+    .and.to.emit(complex, 'TransferredTokens').withArgs(100);
+
+Although you may find it more convenient to write multiple expects. The test below is equivalent to the one above: 
+
+.. code-block:: ts
+
+  await token.approve(complex.address, 100);
+  const tx = await complex.doEverything(receiver.address, 100, {value: 200});
+  await expect(tx).to.changeTokenBalances(token, [sender, receiver], [-100, 100]);
+  await expect(tx).to.changeEtherBalances([sender, receiver], [-200, 200]);
+  await expect(tx).to.emit(complex, 'TransferredEther').withArgs(200);
+  await expect(tx).to.emit(complex, 'TransferredTokens').withArgs(100);
+
+Note that in both cases you can use :code:`chai` negation :code:`not`. In a case of a single expect everything after :code:`not` is negated.
+
+.. code-block:: ts
+
+  await token.approve(complex.address, 100);
+  const tx = await complex.doEverything(receiver.address, 100, {value: 200});
+  await expect(expect(tx)
+    .to.changeTokenBalances(token, [sender, receiver], [-100, 100])
+    .and.to.emit(complex, 'TransferredTokens').withArgs(100)
+    .and.not
+    .to.emit(complex, 'UnusedEvent') // This is negated
+    .and.to.changeEtherBalances([sender, receiver], [-100, 100])  // This is negated as well
diff --git a/waffle-chai/src/matchers/changeBalance.ts b/waffle-chai/src/matchers/changeBalance.ts
@@ -1,32 +1,37 @@
 import {BigNumber, BigNumberish} from 'ethers';
 import {Account, getAddressOf} from './misc/account';
 import {getBalanceChange} from './changeEtherBalance';
+import {transactionPromise} from '../transaction-promise';
 
 export function supportChangeBalance(Assertion: Chai.AssertionStatic) {
   Assertion.addMethod('changeBalance', function (
     this: any,
     account: Account,
     balanceChange: BigNumberish
   ) {
-    const subject = this._obj;
-    const derivedPromise = Promise.all([
-      getBalanceChange(subject, account, {includeFee: true}),
-      getAddressOf(account)
-    ]).then(
-      ([actualChange, address]) => {
-        this.assert(
-          actualChange.eq(BigNumber.from(balanceChange)),
-          `Expected "${address}" to change balance by ${balanceChange} wei, ` +
-          `but it has changed by ${actualChange} wei`,
-          `Expected "${address}" to not change balance by ${balanceChange} wei,`,
-          balanceChange,
-          actualChange
-        );
-      }
-    );
+    transactionPromise(this);
+    const isNegated = this.__flags.negate === true;
+    const derivedPromise = this.txPromise.then(() => {
+      return Promise.all([
+        getBalanceChange(this.txResponse, account, {includeFee: true}),
+        getAddressOf(account)
+      ]);
+    }).then(([actualChange, address]: [BigNumber, string]) => {
+      const isCurrentlyNegated = this.__flags.negate === true;
+      this.__flags.negate = isNegated;
+      this.assert(
+        actualChange.eq(BigNumber.from(balanceChange)),
+        `Expected "${address}" to change balance by ${balanceChange} wei, ` +
+        `but it has changed by ${actualChange} wei`,
+        `Expected "${address}" to not change balance by ${balanceChange} wei,`,
+        balanceChange,
+        actualChange
+      );
+      this.__flags.negate = isCurrentlyNegated;
+    });
     this.then = derivedPromise.then.bind(derivedPromise);
     this.catch = derivedPromise.catch.bind(derivedPromise);
-    this.promise = derivedPromise;
+    this.txPromise = derivedPromise;
     return this;
   });
 }
diff --git a/waffle-chai/src/matchers/changeBalances.ts b/waffle-chai/src/matchers/changeBalances.ts
@@ -1,4 +1,5 @@
 import {BigNumber, BigNumberish} from 'ethers';
+import {transactionPromise} from '../transaction-promise';
 import {getBalanceChanges} from './changeEtherBalances';
 import {Account} from './misc/account';
 import {getAddresses} from './misc/balance';
@@ -9,28 +10,31 @@ export function supportChangeBalances(Assertion: Chai.AssertionStatic) {
     accounts: Account[],
     balanceChanges: BigNumberish[]
   ) {
-    const subject = this._obj;
-
-    const derivedPromise = Promise.all([
-      getBalanceChanges(subject, accounts, {includeFee: true}),
-      getAddresses(accounts)
-    ]).then(
-      ([actualChanges, accountAddresses]) => {
-        this.assert(
-          actualChanges.every((change, ind) =>
-            change.eq(BigNumber.from(balanceChanges[ind]))
-          ),
-          `Expected ${accountAddresses} to change balance by ${balanceChanges} wei, ` +
-            `but it has changed by ${actualChanges} wei`,
-          `Expected ${accountAddresses} to not change balance by ${balanceChanges} wei,`,
-          balanceChanges.map((balanceChange) => balanceChange.toString()),
-          actualChanges.map((actualChange) => actualChange.toString())
-        );
-      }
-    );
+    transactionPromise(this);
+    const isNegated = this.__flags.negate === true;
+    const derivedPromise = this.txPromise.then(() => {
+      return Promise.all([
+        getBalanceChanges(this.txResponse, accounts, {includeFee: true}),
+        getAddresses(accounts)
+      ]);
+    }).then(([actualChanges, accountAddresses]: [BigNumber[], string[]]) => {
+      const isCurrentlyNegated = this.__flags.negate === true;
+      this.__flags.negate = isNegated;
+      this.assert(
+        actualChanges.every((change, ind) =>
+          change.eq(BigNumber.from(balanceChanges[ind]))
+        ),
+        `Expected ${accountAddresses} to change balance by ${balanceChanges} wei, ` +
+          `but it has changed by ${actualChanges} wei`,
+        `Expected ${accountAddresses} to not change balance by ${balanceChanges} wei,`,
+        balanceChanges.map((balanceChange) => balanceChange.toString()),
+        actualChanges.map((actualChange) => actualChange.toString())
+      );
+      this.__flags.negate = isCurrentlyNegated;
+    });
     this.then = derivedPromise.then.bind(derivedPromise);
     this.catch = derivedPromise.catch.bind(derivedPromise);
-    this.promise = derivedPromise;
+    this.txPromise = derivedPromise;
     return this;
   });
 }
diff --git a/waffle-chai/src/matchers/changeEtherBalance.ts b/waffle-chai/src/matchers/changeEtherBalance.ts
@@ -1,4 +1,5 @@
 import {BigNumber, BigNumberish, providers} from 'ethers';
+import {transactionPromise} from '../transaction-promise';
 import {ensure} from './calledOnContract/utils';
 import {Account, getAddressOf} from './misc/account';
 import {BalanceChangeOptions} from './misc/balance';
@@ -10,53 +11,48 @@ export function supportChangeEtherBalance(Assertion: Chai.AssertionStatic) {
     balanceChange: BigNumberish,
     options: BalanceChangeOptions
   ) {
-    const subject = this._obj;
-    const derivedPromise = Promise.all([
-      getBalanceChange(subject, account, options),
-      getAddressOf(account)
-    ]).then(
-      ([actualChange, address]) => {
-        this.assert(
-          actualChange.eq(BigNumber.from(balanceChange)),
-          `Expected "${address}" to change balance by ${balanceChange} wei, ` +
+    transactionPromise(this);
+    const isNegated = this.__flags.negate === true;
+    const derivedPromise = this.txPromise.then(() => {
+      return Promise.all([
+        getBalanceChange(this.txResponse, account, options),
+        getAddressOf(account)
+      ]);
+    }).then(([actualChange, address]: [BigNumber, string]) => {
+      const isCurrentlyNegated = this.__flags.negate === true;
+      this.__flags.negate = isNegated;
+      this.assert(
+        actualChange.eq(BigNumber.from(balanceChange)),
+        `Expected "${address}" to change balance by ${balanceChange} wei, ` +
           `but it has changed by ${actualChange} wei`,
-          `Expected "${address}" to not change balance by ${balanceChange} wei,`,
-          balanceChange,
-          actualChange
-        );
-      }
+        `Expected "${address}" to not change balance by ${balanceChange} wei,`,
+        balanceChange,
+        actualChange
+      );
+      this.__flags.negate = isCurrentlyNegated;
+    }
     );
     this.then = derivedPromise.then.bind(derivedPromise);
     this.catch = derivedPromise.catch.bind(derivedPromise);
-    this.promise = derivedPromise;
+    this.txPromise = derivedPromise;
     return this;
   });
 }
 
 export async function getBalanceChange(
-  transaction:
-  | providers.TransactionResponse
-  | (() => Promise<providers.TransactionResponse> | providers.TransactionResponse),
+  txResponse: providers.TransactionResponse,
   account: Account,
   options?: BalanceChangeOptions
 ) {
   ensure(account.provider !== undefined, TypeError, 'Provider not found');
-
-  let txResponse: providers.TransactionResponse;
-
-  if (typeof transaction === 'function') {
-    txResponse = await transaction();
-  } else {
-    txResponse = transaction;
-  }
-
   const txReceipt = await txResponse.wait();
   const txBlockNumber = txReceipt.blockNumber;
+  const address = await getAddressOf(account);
 
-  const balanceAfter = await account.provider.getBalance(getAddressOf(account), txBlockNumber);
-  const balanceBefore = await account.provider.getBalance(getAddressOf(account), txBlockNumber - 1);
+  const balanceAfter = await account.provider.getBalance(address, txBlockNumber);
+  const balanceBefore = await account.provider.getBalance(address, txBlockNumber - 1);
 
-  if (options?.includeFee !== true && await getAddressOf(account) === txResponse.from) {
+  if (options?.includeFee !== true && address === txReceipt.from) {
     const gasPrice = txResponse.gasPrice ?? txReceipt.effectiveGasPrice;
     const gasUsed = txReceipt.gasUsed;
     const txFee = gasPrice.mul(gasUsed);

diff --git a/waffle-chai/src/matchers/changeEtherBalances.ts b/waffle-chai/src/matchers/changeEtherBalances.ts
@@ -1,4 +1,5 @@
 import {BigNumber, BigNumberish, providers} from 'ethers';
+import {transactionPromise} from '../transaction-promise';
 import {getAddressOf, Account} from './misc/account';
 import {BalanceChangeOptions, getAddresses, getBalances} from './misc/balance';
 
@@ -9,47 +10,40 @@ export function supportChangeEtherBalances(Assertion: Chai.AssertionStatic) {
     balanceChanges: BigNumberish[],
     options: BalanceChangeOptions
   ) {
-    const subject = this._obj;
-
-    const derivedPromise = Promise.all([
-      getBalanceChanges(subject, accounts, options),
-      getAddresses(accounts)
-    ]).then(
-      ([actualChanges, accountAddresses]) => {
-        this.assert(
-          actualChanges.every((change, ind) =>
-            change.eq(BigNumber.from(balanceChanges[ind]))
-          ),
-          `Expected ${accountAddresses} to change balance by ${balanceChanges} wei, ` +
-            `but it has changed by ${actualChanges} wei`,
-          `Expected ${accountAddresses} to not change balance by ${balanceChanges} wei,`,
-          balanceChanges.map((balanceChange) => balanceChange.toString()),
-          actualChanges.map((actualChange) => actualChange.toString())
-        );
-      }
-    );
+    transactionPromise(this);
+    const isNegated = this.__flags.negate === true;
+    const derivedPromise = this.txPromise.then(() => {
+      return Promise.all([
+        getBalanceChanges(this.txResponse, accounts, options),
+        getAddresses(accounts)
+      ]);
+    }).then(([actualChanges, accountAddresses]: [BigNumber[], string[]]) => {
+      const isCurrentlyNegated = this.__flags.negate === true;
+      this.__flags.negate = isNegated;
+      this.assert(
+        actualChanges.every((change, ind) =>
+          change.eq(BigNumber.from(balanceChanges[ind]))
+        ),
+        `Expected ${accountAddresses} to change balance by ${balanceChanges} wei, ` +
+          `but it has changed by ${actualChanges} wei`,
+        `Expected ${accountAddresses} to not change balance by ${balanceChanges} wei,`,
+        balanceChanges.map((balanceChange) => balanceChange.toString()),
+        actualChanges.map((actualChange) => actualChange.toString())
+      );
+      this.__flags.negate = isCurrentlyNegated;
+    });
     this.then = derivedPromise.then.bind(derivedPromise);
     this.catch = derivedPromise.catch.bind(derivedPromise);
-    this.promise = derivedPromise;
+    this.txPromise = derivedPromise;
     return this;
   });
 }
 
 export async function getBalanceChanges(
-  transaction:
-  | providers.TransactionResponse
-  | (() => Promise<providers.TransactionResponse> | providers.TransactionResponse),
+  txResponse: providers.TransactionResponse,
   accounts: Account[],
   options: BalanceChangeOptions
 ) {
-  let txResponse: providers.TransactionResponse;
-
-  if (typeof transaction === 'function') {
-    txResponse = await transaction();
-  } else {
-    txResponse = transaction;
-  }
-
   const txReceipt = await txResponse.wait();
   const txBlockNumber = txReceipt.blockNumber;