test: refactor common.expectsError()

* Report values in assertions.
* Strict equality match if message is a string.
* instanceof/typeof instead of deprecated util.isRegExp()

PR-URL: nodejs#11381
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>

test/common.js

@@ -626,11 +626,13 @@ exports.expectsError = function expectsError(code, type, message) {
   return function(error) {
     assert.strictEqual(error.code, code);
     if (type !== undefined)
-      assert(error instanceof type, 'error is not the expected type');
-    if (message !== undefined) {
-      if (!util.isRegExp(message))
-        message = new RegExp(String(message));
-      assert(message.test(error.message), 'error.message does not match');
+      assert(error instanceof type,
+             `${error} is not the expected type ${type}`);
+    if (message instanceof RegExp) {
+      assert(message.test(error.message),
+             `${error.message} does not match ${message}`);
+    } else if (typeof message === 'string') {
+      assert.strictEqual(error.message, message);
     }
     return true;
   };

test/parallel/test-internal-errors.js

@@ -107,10 +107,10 @@ assert.throws(() => {
   assert.throws(() => {
     throw new errors.TypeError('TEST_ERROR_1', 'a');
   }, common.expectsError('TEST_ERROR_1', RangeError));
-}, /^AssertionError: error is not the expected type/);
+}, /^AssertionError: .+ is not the expected type \S/);
 
 assert.throws(() => {
   assert.throws(() => {
     throw new errors.TypeError('TEST_ERROR_1', 'a');
   }, common.expectsError('TEST_ERROR_1', TypeError, /^Error for testing 2/));
-}, /^AssertionError: error.message does not match/);
+}, /AssertionError: .+ does not match \S/);