function assertMessageMatches(actual, expected) {
			if (expected instanceof RegExp) {
				// assert.js doesn't have a built-in RegExp match function
				assert.ok(
					expected.test(actual),
					`Expected '${actual}' to match ${expected}`,
				);
			} else {
				assert.strictEqual(actual, expected);
			}
		}
Asserts that the message matches its expected value. If the expected
value is a regular expression, it is checked against the actual
value.
@param {string} actual Actual value
@param {string|RegExp} expected Expected value
@returns {void}
@private