added test for early bail when errors are present

simplified conditionals using lodash `.get`

controller/search.js

@@ -11,14 +11,14 @@ function setup( apiConfig, esclient, query ){
   function controller( req, res, next ){
     // do not run controller when a request
     // validation error has occurred.
-    if( req.errors && req.errors.length ){
+    if (_.get(req, 'errors', []).length > 0) {
       return next();
     }
 
     // do not run controller if there are already results
     // this was added during libpostal integration.  if the libpostal parse/query
     // doesn't return anything then fallback to old search-engine-y behavior
-    if (res && res.hasOwnProperty('data') && res.data.length > 0) {
+    if (_.get(res, 'data', []).length > 0) {
       return next();
     }
 

test/unit/controller/search.js

@@ -173,6 +173,29 @@ module.exports.tests.timeout = function(test, common) {
   });
 };
 
+module.exports.tests.existing_errors = function(test, common) {
+  test('req with errors should not call backend', function(t) {
+    var esclient = function() {
+      throw new Error('esclient should not have been called');
+    };
+    var controller = setup( fakeDefaultConfig, esclient, mockQuery() );
+
+    // the existence of `errors` means that a sanitizer detected an error,
+    //  so don't call the esclient
+    var req = {
+      errors: ['error']
+    };
+    var res = { };
+
+    t.doesNotThrow(() => {
+      controller(req, res, () => {});
+    });
+    t.end();
+
+  });
+
+};
+
 module.exports.tests.existing_results = function(test, common) {
   test('res with existing data should not call backend', function(t) {
     var backend = function() {