Added a comment and fixed test

src/snapshots.js

@@ -188,6 +188,14 @@ export async function* takeStorybookSnapshots(percy, callback, { baseUrl, flags
     // set storybook environment info
     percy.client.addEnvironmentInfo(environmentInfo);
 
+    // We use an outer and inner loop on same snapshots.length
+    // - we create a new page and load one story on it at a time for snapshotting
+    // - if it throws exception then we want to catch it outside of `withPage` call as
+    //   when `withPage` returns it closes the page
+    // - we want to make sure we close the page that had exception in story to make sure
+    //   we dont reuse a page which is possibly in a weird state due to last exception
+    // - so post exception we come out of inner loop and skip the story, create new page
+    //   using outer loop and continue next stories again on a new page
     while (snapshots.length) {
       try {
         // use a single page to capture story snapshots without reloading

test/storybook.test.js

@@ -181,7 +181,9 @@ describe('percy storybook', () => {
       expect(logger.stderr).toEqual([
         '[percy] Failed to capture story: foo: bar',
         // error logs contain the client stack trace
-        jasmine.stringMatching(/^\[percy\] Error: Story Error\n.*\/iframe\.html.*$/s)
+        jasmine.stringMatching(/^\[percy\] Error: Story Error\n.*\/iframe\.html.*$/s),
+        // does not create a build if all stories failed [ 1 in this case ]
+        '[percy] Build not created'
       ]);
     });
   });