From 97c52ca5dc0b9c4df015dc36ef394ebe06ec00c6 Mon Sep 17 00:00:00 2001
From: Ruben Bridgewater <ruben@bridgewater.de>
Date: Sat, 15 Jun 2019 13:27:21 +0200
Subject: [PATCH] assert: add more information to AssertionErrors

This adds information about the actual thrown error to the
AssertionError's message property.

It also improves the logged error instances error name by using the
constructors name, if available.

PR-URL: https://github.com/nodejs/node/pull/28263
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
---
 lib/assert.js                      | 11 ++++++++++-
 test/parallel/test-assert-async.js |  3 ++-
 test/parallel/test-assert.js       |  7 ++++---
 3 files changed, 16 insertions(+), 5 deletions(-)

diff --git a/lib/assert.js b/lib/assert.js
index 50ab6b39b161bb..0b256e604eeb0e 100644
--- a/lib/assert.js
+++ b/lib/assert.js
@@ -620,8 +620,13 @@ function expectedException(actual, expected, message, fn) {
       generatedMessage = true;
       message = 'The error is expected to be an instance of ' +
         `"${expected.name}". Received `;
+      // TODO: Special handle identical names.
       if (isError(actual)) {
-        message += `"${actual.name}"`;
+        const name = actual.constructor && actual.constructor.name;
+        message += `"${name || actual.name}"`;
+        if (actual.message) {
+          message += `\n\nError message:\n\n${actual.message}`;
+        }
       } else {
         message += `"${inspect(actual, { depth: -1 })}"`;
       }
@@ -636,6 +641,10 @@ function expectedException(actual, expected, message, fn) {
         const name = expected.name ? `"${expected.name}" ` : '';
         message = `The ${name}validation function is expected to return` +
           ` "true". Received ${inspect(res)}`;
+
+        if (isError(actual)) {
+          message += `\n\nCaught error:\n\n${actual}`;
+        }
       }
       throwError = true;
     }
diff --git a/test/parallel/test-assert-async.js b/test/parallel/test-assert-async.js
index 45447d456379e1..cbb4431f1952df 100644
--- a/test/parallel/test-assert-async.js
+++ b/test/parallel/test-assert-async.js
@@ -73,7 +73,8 @@ const invalidThenableFunc = () => {
     () => assert.rejects(Promise.reject(err), validate),
     {
       message: 'The "validate" validation function is expected to ' +
-               "return \"true\". Received 'baz'",
+               "return \"true\". Received 'baz'\n\nCaught error:\n\n" +
+               'Error: foobar',
       code: 'ERR_ASSERTION',
       actual: err,
       expected: validate,
diff --git a/test/parallel/test-assert.js b/test/parallel/test-assert.js
index 9c59227a78492e..07cf3746965870 100644
--- a/test/parallel/test-assert.js
+++ b/test/parallel/test-assert.js
@@ -133,7 +133,7 @@ assert.throws(
     name: 'AssertionError',
     operator: 'throws',
     message: 'The error is expected to be an instance of "AssertionError". ' +
-             'Received "TypeError"'
+             'Received "TypeError"\n\nError message:\n\n[object Object]'
   }
 );
 
@@ -255,7 +255,7 @@ a.throws(() => thrower(TypeError), (err) => {
       assert.strictEqual(
         err.message,
         'The error is expected to be an instance of "ES6Error". ' +
-          'Received "Error"'
+          'Received "AnotherErrorType"\n\nError message:\n\nfoo'
       );
       assert.strictEqual(err.actual, actual);
       return true;
@@ -1334,7 +1334,8 @@ assert.throws(
     () => assert.throws(() => { throw err; }, validate),
     {
       message: 'The validation function is expected to ' +
-              `return "true". Received ${inspect(validate())}`,
+              `return "true". Received ${inspect(validate())}\n\nCaught ` +
+              `error:\n\n${err}`,
       code: 'ERR_ASSERTION',
       actual: err,
       expected: validate,