assert: use util.inspect() to create error messages

cjihrig · Julien Gilli · commit bcff90e0c299 · 2015-01-29T15:22:15.000-08:00
Currently, JSON.stringify() is used to create error messages on failed assertions. This causes an error when stringifying objects with circular references. This commit switches out JSON.stringify() for util.inspect(), which can handle circular references. PR: #8734 PR-URL: #8734 Reviewed-By: Julien Gilli <julien.gilli@joyent.com>
diff --git a/lib/assert.js b/lib/assert.js
@@ -57,19 +57,6 @@ assert.AssertionError = function AssertionError(options) {
 // assert.AssertionError instanceof Error
 util.inherits(assert.AssertionError, Error);
 
-function replacer(key, value) {
-  if (util.isUndefined(value)) {
-    return '' + value;
-  }
-  if (util.isNumber(value) && !isFinite(value)) {
-    return value.toString();
-  }
-  if (util.isFunction(value) || util.isRegExp(value)) {
-    return value.toString();
-  }
-  return value;
-}
-
 function truncate(s, n) {
   if (util.isString(s)) {
     return s.length < n ? s : s.slice(0, n);
@@ -79,9 +66,9 @@ function truncate(s, n) {
 }
 
 function getMessage(self) {
-  return truncate(JSON.stringify(self.actual, replacer), 128) + ' ' +
+  return truncate(util.inspect(self.actual, {depth: null}), 128) + ' ' +
          self.operator + ' ' +
-         truncate(JSON.stringify(self.expected, replacer), 128);
+         truncate(util.inspect(self.expected, {depth: null}), 128);
 }
 
 // At present only the three keys mentioned above are used and
diff --git a/test/simple/test-assert.js b/test/simple/test-assert.js
@@ -258,36 +258,40 @@ console.log('All OK');
 assert.ok(gotError);
 
 
-// #217
+var circular = {y: 1};
+circular.x = circular;
+
 function testAssertionMessage(actual, expected) {
   try {
     assert.equal(actual, '');
   } catch (e) {
     assert.equal(e.toString(),
-        ['AssertionError:', expected, '==', '""'].join(' '));
+        ['AssertionError:', expected, '==', '\'\''].join(' '));
     assert.ok(e.generatedMessage, "Message not marked as generated");
   }
 }
-testAssertionMessage(undefined, '"undefined"');
+testAssertionMessage(undefined, 'undefined');
 testAssertionMessage(null, 'null');
 testAssertionMessage(true, 'true');
 testAssertionMessage(false, 'false');
 testAssertionMessage(0, '0');
 testAssertionMessage(100, '100');
-testAssertionMessage(NaN, '"NaN"');
-testAssertionMessage(Infinity, '"Infinity"');
-testAssertionMessage(-Infinity, '"-Infinity"');
+testAssertionMessage(NaN, 'NaN');
+testAssertionMessage(Infinity, 'Infinity');
+testAssertionMessage(-Infinity, '-Infinity');
 testAssertionMessage('', '""');
-testAssertionMessage('foo', '"foo"');
+testAssertionMessage('foo', '\'foo\'');
 testAssertionMessage([], '[]');
-testAssertionMessage([1, 2, 3], '[1,2,3]');
-testAssertionMessage(/a/, '"/a/"');
-testAssertionMessage(/abc/gim, '"/abc/gim"');
-testAssertionMessage(function f() {}, '"function f() {}"');
+testAssertionMessage([1, 2, 3], '[ 1, 2, 3 ]');
+testAssertionMessage(/a/, '/a/');
+testAssertionMessage(/abc/gim, '/abc/gim');
+testAssertionMessage(function f() {}, '[Function: f]');
+testAssertionMessage(function () {}, '[Function]');
 testAssertionMessage({}, '{}');
-testAssertionMessage({a: undefined, b: null}, '{"a":"undefined","b":null}');
+testAssertionMessage(circular, '{ y: 1, x: [Circular] }');
+testAssertionMessage({a: undefined, b: null}, '{ a: undefined, b: null }');
 testAssertionMessage({a: NaN, b: Infinity, c: -Infinity},
-    '{"a":"NaN","b":"Infinity","c":"-Infinity"}');
+    '{ a: NaN, b: Infinity, c: -Infinity }');
 
 // #2893
 try {
