Add a test for order, fix existing tests

lib/client-api/src/story_store.test.js

@@ -191,4 +191,29 @@ describe('preview.story_store', () => {
       expect(store.setSelection.mock.calls[0][0].getDecorated()).toEqual(storyFn);
     });
   });
+
+  describe('story sorting', () => {
+    const storySort = (a, b) => a[1].id.localeCompare(b[1].id);
+    it('should use the sorting function of the story parameter object', () => {
+      const store = new StoryStore({ channel });
+      store.addStory(
+        ...make('kind-2', 'a-story-2.1', () => 0, { fileName: 'bar.js', options: { storySort } })
+      );
+      store.addStory(
+        ...make('kind-1', 'z-story-1.1', () => 0, { fileName: 'foo.js', options: { storySort } })
+      );
+      store.addStory(
+        ...make('kind-1', 'story-1.2', () => 0, { fileName: 'foo-2.js', options: { storySort } })
+      );
+      store.addStory(
+        ...make('kind-2', 'story-2.1', () => 0, { fileName: 'bar.js', options: { storySort } })
+      );
+
+      const stories = Object.values(store.extract());
+      expect(stories[0].id).toBe('kind-1--story-1-2');
+      expect(stories[1].id).toBe('kind-1--z-story-1-1');
+      expect(stories[2].id).toBe('kind-2--a-story-2-1');
+      expect(stories[3].id).toBe('kind-2--story-2-1');
+    });
+  });
 });

lib/ui/src/components/sidebar/treeview/utils.test.js

@@ -164,7 +164,7 @@ describe('getPrevious', () => {
       id: '3-31',
       ...withRoot,
     });
-    expect(output).toBe(withRoot.dataset['1-12']);
+    expect(output).toBe(withRoot.dataset['2']);
   });
 });
 
@@ -210,7 +210,7 @@ describe('getNext', () => {
   });
   test('to next parent with root as parent - skip root', () => {
     const output = utils.getNext({ id: '1-12', ...withRoot });
-    expect(output).toBe(withRoot.dataset['3-31']);
+    expect(output).toBe(withRoot.dataset['2']);
   });
 });