Fix commented out Tests for loading Search Results

Fix the commented out tests for loading SearchBox search results and
rendering them with HTML, due to an asynchronous problem when running
tests, where occasionally the answer will change depending on whether
the results come back in time; meaning one of two answers will be true
and the other false, depending on when it is called or if it is called
multiple times; e.g.

```javascript
    it('_getResults (after AJAX request with no params)', function (done) {
      const _subject = new describedClass();

      _subject.reRenderCallback = function expectedResults(component, _) {
        const results = component._getResults();
        expect([
          jasmine.any(NullSearchResult),
          jasmine.any(NullComponent)
        ]).toContain(results);
      };

      _subject._searchFromServer('', '', '', function(_error, searchbox) {
        var results = searchbox._getResults();
        expect(results).toEqual(jasmine.any(NullSearchResult));
        done();
      });
    });
```

The SearchBox will be rendered normally on first load containing a
`NullComponent` as a placeholder component until results are loaded, in
this case it returns no results for an empty search and then renders a
`NullSearchResult` component. However, the test will fail unless it is
true for at least one of them when the other is not present; i.e.

- Is true when it renders `NullComponent`    and not `NullSearchResult`,
  and
- Is true when it renders `NulLSearchResult` and not `NullComponent`,
  but
- Is not true when it only renders one of them (since one or the other
  is rendered at some point in the future)

== Notes:
- Some tests have remained disabled since the
  `'_searchFromServer returns expected flights data'` test
  only returns expected results data if `_searchFromServer()` is not
  called multiple time prior to it (meaning it may fail on other
  computers <sigh>)

== References:
- [Pass callback to wrapper.setState · Issue #509 · airbnb/enzyme]
  (enzymejs/enzyme#509)

- [node.js - How do I change the timeout on a jasmine-node async spec - Stack Overflow]
  (https://stackoverflow.com/questions/9867601/how-do-i-change-the-timeout-on-a-jasmine-node-async-spec)

lib/components/SearchBox.js

@@ -43,13 +43,15 @@ function SearchBox(properties) {
   this.setState(properties);
 };
 
-SearchBox.prototype.setState = function (properties) {
+SearchBox.prototype.setState = function (properties, callback) {
   this.state = Object.assign({}, this.state, properties);
 
   var self = this;
   var parentEl = this.reRenderLocation;
   // this.update(self, parentEl);
   this.reRenderCallback(self, parentEl);
+
+  (typeof callback === 'function') && callback(null, self);
 };
 
 SearchBox.prototype.render = function () {
@@ -144,7 +146,7 @@ function travelDates(travelDate) {
 }
 
 // SearchBox.prototype._updateResults = function (from, to, travel_date) {
-SearchBox.prototype._searchFromServer = function (from, to, travelDate) {
+SearchBox.prototype._searchFromServer = function (from, to, travelDate, callback) {
   var self = this;
   var promises = travelDates(travelDate).map(function (newTravelDate) {
     return new Promise(function (success, fail) {
@@ -181,29 +183,28 @@ SearchBox.prototype._searchFromServer = function (from, to, travelDate) {
     results: self.state.results
   });
 
-  return Promise.all(promises)
+  Promise.all(promises)
     .then(function (results) {
+      // Remove empty results
       var reducedResults = results.reduce(function (obj, item) {
         if(item.value.length > 0) {
           obj[item.key] = item.value;
         }
         return obj;
       }, {});
 
+      // Update SearchBox with results and stop loading animation
       self.setState({
         hasUpdatedResults: true,
         from: from,
         to: to,
         travelDate: travelDate,
         loadingResults: false,
         results: reducedResults
-      });
-      // (typeof callback === 'function') && callback(null, results);
-      return self;
+      }, callback);
     }).catch(function (error) {
       console.log(error);
-      // (typeof callback === 'function') && callback(error, {});
-      return error;
+      (typeof callback === 'function') && callback(error, {});
     });
 }