dexorder

lib_openzeppelin_contracts/test/token/ERC20/extensions/ERC20Burnable.test.js

@@ -0,0 +1,105 @@
+const { ethers } = require('hardhat');
+const { expect } = require('chai');
+const { loadFixture } = require('@nomicfoundation/hardhat-network-helpers');
+
+const name = 'My Token';
+const symbol = 'MTKN';
+const initialBalance = 1000n;
+
+async function fixture() {
+  const [owner, burner] = await ethers.getSigners();
+
+  const token = await ethers.deployContract('$ERC20Burnable', [name, symbol], owner);
+  await token.$_mint(owner, initialBalance);
+
+  return { owner, burner, token, initialBalance };
+}
+
+describe('ERC20Burnable', function () {
+  beforeEach(async function () {
+    Object.assign(this, await loadFixture(fixture));
+  });
+
+  describe('burn', function () {
+    it('reverts if not enough balance', async function () {
+      const value = this.initialBalance + 1n;
+
+      await expect(this.token.connect(this.owner).burn(value))
+        .to.be.revertedWithCustomError(this.token, 'ERC20InsufficientBalance')
+        .withArgs(this.owner, this.initialBalance, value);
+    });
+
+    describe('on success', function () {
+      for (const { title, value } of [
+        { title: 'for a zero value', value: 0n },
+        { title: 'for a non-zero value', value: 100n },
+      ]) {
+        describe(title, function () {
+          beforeEach(async function () {
+            this.tx = await this.token.connect(this.owner).burn(value);
+          });
+
+          it('burns the requested value', async function () {
+            await expect(this.tx).to.changeTokenBalance(this.token, this.owner, -value);
+          });
+
+          it('emits a transfer event', async function () {
+            await expect(this.tx).to.emit(this.token, 'Transfer').withArgs(this.owner, ethers.ZeroAddress, value);
+          });
+        });
+      }
+    });
+  });
+
+  describe('burnFrom', function () {
+    describe('reverts', function () {
+      it('if not enough balance', async function () {
+        const value = this.initialBalance + 1n;
+
+        await this.token.connect(this.owner).approve(this.burner, value);
+
+        await expect(this.token.connect(this.burner).burnFrom(this.owner, value))
+          .to.be.revertedWithCustomError(this.token, 'ERC20InsufficientBalance')
+          .withArgs(this.owner, this.initialBalance, value);
+      });
+
+      it('if not enough allowance', async function () {
+        const allowance = 100n;
+
+        await this.token.connect(this.owner).approve(this.burner, allowance);
+
+        await expect(this.token.connect(this.burner).burnFrom(this.owner, allowance + 1n))
+          .to.be.revertedWithCustomError(this.token, 'ERC20InsufficientAllowance')
+          .withArgs(this.burner, allowance, allowance + 1n);
+      });
+    });
+
+    describe('on success', function () {
+      for (const { title, value } of [
+        { title: 'for a zero value', value: 0n },
+        { title: 'for a non-zero value', value: 100n },
+      ]) {
+        describe(title, function () {
+          const originalAllowance = value * 3n;
+
+          beforeEach(async function () {
+            await this.token.connect(this.owner).approve(this.burner, originalAllowance);
+            this.tx = await this.token.connect(this.burner).burnFrom(this.owner, value);
+          });
+
+          it('burns the requested value', async function () {
+            await expect(this.tx).to.changeTokenBalance(this.token, this.owner, -value);
+          });
+
+          it('decrements allowance', async function () {
+            expect(await this.token.allowance(this.owner, this.burner)).to.equal(originalAllowance - value);
+          });
+
+          it('emits a transfer event', async function () {
+            await expect(this.tx).to.emit(this.token, 'Transfer').withArgs(this.owner, ethers.ZeroAddress, value);
+          });
+        });
+      }
+    });
+  });
+});