assert: refactor AssertionError properties

lib/internal/assert.js

@@ -395,6 +395,14 @@ class AssertionError extends Error {
     this.operator = operator;
     Error.captureStackTrace(this, stackStartFn);
   }
+
+  [inspect.custom](recurseTimes, ctx) {
+    // This limits the `actual` and `expected` property default inspection to
+    // the minimum depth. Otherwise those values would be to verbose compared
+    // to the actual error message which contains a combined view of these two
+    // input values.
+    return inspect(this, { ...ctx, customInspect: false, depth: 0 });
+  }
 }
 
 module.exports = {

test/parallel/test-assert.js

@@ -257,16 +257,14 @@ const circular = { y: 1 };
 circular.x = circular;
 
 function testAssertionMessage(actual, expected, msg) {
-  try {
-    assert.strictEqual(actual, '');
-  } catch (e) {
-    assert.strictEqual(
-      e.message,
-      msg || strictEqualMessageStart +
-             `+ actual - expected\n\n+ ${expected}\n- ''`
-    );
-    assert.ok(e.generatedMessage, 'Message not marked as generated');
-  }
+  assert.throws(
+    () => assert.strictEqual(actual, ''),
+    {
+      generatedMessage: true,
+      message: msg || strictEqualMessageStart +
+               `+ actual - expected\n\n+ ${expected}\n- ''`
+    }
+  );
 }
 
 function testShortAssertionMessage(actual, expected) {
@@ -280,7 +278,7 @@ testShortAssertionMessage(false, 'false');
 testShortAssertionMessage(100, '100');
 testShortAssertionMessage(NaN, 'NaN');
 testShortAssertionMessage(Infinity, 'Infinity');
-testShortAssertionMessage('', '""');
+testShortAssertionMessage('a', '"a"');
 testShortAssertionMessage('foo', '\'foo\'');
 testShortAssertionMessage(0, '0');
 testShortAssertionMessage(Symbol(), 'Symbol()');
@@ -1139,3 +1137,14 @@ assert.throws(
              '{\n  a: true\n}\n'
   }
 );
+
+{
+  let threw = false;
+  try {
+    assert.deepStrictEqual(Array(100).fill(1), 'foobar');
+  } catch (err) {
+    threw = true;
+    assert(/actual: \[Array],\n  expected: 'foobar',/.test(inspect(err)));
+  }
+  assert(threw);
+}