Adds failing test

Author: Andrew Bradley

test/test-source-map-consumer.js

@@ -270,6 +270,11 @@ exports['test eachMapping'] = function (assert) {
   map.eachMapping(function (mapping) {
     assert.ok(mapping.source === 'one.js' || mapping.source === 'two.js');
   });
+
+  map = new SourceMapConsumer(util.mapWithSourcelessMapping);
+  map.eachMapping(function (mapping) {
+    assert.ok(mapping.source === null || (typeof mapping.originalColumn === 'number' && typeof mapping.originalLine === 'number'));
+  });
 };
 
 exports['test eachMapping for indexed source maps'] = function(assert) {

test/util.js

@@ -249,6 +249,13 @@ exports.emptyMap = {
   sources: [],
   mappings: ''
 };
+exports.mapWithSourcelessMapping = {
+  version: 3,
+  file: 'example.js',
+  names: [],
+  sources: ['example.js'],
+  mappings: 'AAgCA,C'
+};
 
 
 function assertMapping(generatedLine, generatedColumn, originalSource,