use json-stringify-safe in render.js to not throw on circular structures

lib/render.js

@@ -1,5 +1,6 @@
 var Stream = require('stream');
 var json = typeof JSON === 'object' ? JSON : require('jsonify');
+var getSerialize = require('json-stringify-safe').getSerialize()
 
 module.exports = Render;
 
@@ -70,8 +71,8 @@ function encodeResult (res, count) {
         output += outer + '---\n';
         output += inner + 'operator: ' + res.operator + '\n';
 
-        var ex = json.stringify(res.expected) || '';
-        var ac = json.stringify(res.actual) || '';
+        var ex = json.stringify(res.expected, getSerialize) || '';
+        var ac = json.stringify(res.actual, getSerialize) || '';
 
         if (Math.max(ex.length, ac.length) > 65) {
             output += inner + 'expected:\n' + inner + '  ' + ex + '\n';

package.json

@@ -11,7 +11,8 @@
     "dependencies" : {
         "jsonify" : "~0.0.0",
         "deep-equal" : "~0.0.0",
-        "defined" : "~0.0.0"
+        "defined" : "~0.0.0",
+        "json-stringify-safe": "~4.0.0"
     },
     "devDependencies" : {
         "tap" : "~0.3.0",

test/circular-things.js

@@ -0,0 +1,43 @@
+var tape = require('../');
+var tap = require('tap');
+
+tap.test('circular test', function (assert) {
+    var test = tape.createHarness({ exit : false });
+    var tc = tap.createConsumer();
+
+    var rows = [];
+    tc.on('data', function (r) { rows.push(r) });
+    tc.on('end', function () {
+        // console.log("rs", rows)
+
+        // console.log("deepEqual?")
+
+        assert.same(rows, [
+            "TAP version 13"
+            , "circular"
+            , { id: 1
+                , ok: false
+                , name: " should be equal"
+                , operator: "equal"
+                , expected: "{}"
+                , actual: '{"circular":"[Circular]"}'
+            }
+            , "tests 1"
+            , "pass  0"
+            , "fail  1"
+        ])
+        assert.end()
+    })
+
+    // tt.equal(10, 10)
+    // tt.end()
+
+    test.stream.pipe(tc);
+
+    test("circular", function (t) {
+        t.plan(1)
+        var circular = {}
+        circular.circular = circular
+        t.equal(circular, {})
+    })
+})