expected, actual, and operator keys in yaml-esque format on assertion failures

Author: James Halliday

lib/render.js

@@ -1,4 +1,5 @@
 var Stream = require('stream');
+var json = typeof JSON === 'object' ? JSON : require('jsonify');
 
 module.exports = Render;
 
@@ -57,5 +58,27 @@ function encodeResult (res, count) {
     else if (res.todo) output += ' # TODO';
 
     output += '\n';
+    
+    if (!res.ok) {
+        var outer = Array(res.indent + 3).join(' ');
+        var inner = outer + '  ';
+        output += outer + '---\n';
+        output += inner + 'operator: ' + res.operator + '\n';
+        
+        var ex = json.stringify(res.expected);
+        var ac = json.stringify(res.actual);
+        
+        if (Math.max(ex.length, ac.length) > 65) {
+            output += inner + 'expected:\n' + inner + '  ' + ex + '\n';
+            output += inner + 'actual:\n' + inner + '  ' + ac + '\n';
+        }
+        else {
+            output += inner + 'expected: ' + ex + '\n';
+            output += inner + 'actual:   ' + ac + '\n';
+        }
+        
+        output += outer + '...\n';
+    }
+    
     return output;
 }