Replace revert strings with custom errors (#4261)

Co-authored-by: Hadrien Croubois <hadrien.croubois@gmail.com>
Co-authored-by: Francisco <fg@frang.io>

test/helpers/customError.js

@@ -1,21 +1,42 @@
-const { config } = require('hardhat');
-
-const optimizationsEnabled = config.solidity.compilers.some(c => c.settings.optimizer.enabled);
+const { expect } = require('chai');
 
 /** Revert handler that supports custom errors. */
-async function expectRevertCustomError(promise, reason) {
+async function expectRevertCustomError(promise, expectedErrorName, args) {
   try {
     await promise;
     expect.fail("Expected promise to throw but it didn't");
   } catch (revert) {
-    if (reason) {
-      if (optimizationsEnabled) {
-        // Optimizations currently mess with Hardhat's decoding of custom errors
-        expect(revert.message).to.include.oneOf([reason, 'unrecognized return data or custom error']);
-      } else {
-        expect(revert.message).to.include(reason);
-      }
+    if (!Array.isArray(args)) {
+      expect.fail('Expected 3rd array parameter for error arguments');
     }
+    // The revert message for custom errors looks like:
+    // VM Exception while processing transaction:
+    // reverted with custom error 'InvalidAccountNonce("0x70997970C51812dc3A010C7d01b50e0d17dc79C8", 0)'
+
+    // We trim out anything inside the single quotes as comma-separated values
+    const [, error] = revert.message.match(/'(.*)'/);
+
+    // Attempt to parse as an error
+    const match = error.match(/(?<name>\w+)\((?<args>.*)\)/);
+    if (!match) {
+      expect.fail(`Couldn't parse "${error}" as a custom error`);
+    }
+    // Extract the error name and parameters
+    const errorName = match.groups.name;
+    const argMatches = [...match.groups.args.matchAll(/-?\w+/g)];
+
+    // Assert error name
+    expect(errorName).to.be.equal(
+      expectedErrorName,
+      `Unexpected custom error name (with found args: [${argMatches.map(([a]) => a)}])`,
+    );
+
+    // Coerce to string for comparison since `arg` can be either a number or hex.
+    const sanitizedExpected = args.map(arg => arg.toString().toLowerCase());
+    const sanitizedActual = argMatches.map(([arg]) => arg.toString().toLowerCase());
+
+    // Assert argument equality
+    expect(sanitizedActual).to.have.members(sanitizedExpected, `Unexpected ${errorName} arguments`);
   }
 }