feat(screenshot): update to use stencil e2e screenshot testing

core/scripts/screenshot/local.js

@@ -0,0 +1,33 @@
+const ScreenshotConnector = require('@stencil/core/screenshot/screenshot-connector');
+const fs = require('fs');
+const path = require('path');
+
+
+class LocalScreenshotConnector extends ScreenshotConnector {
+
+  async pullMasterImages() {
+    const timespan = this.logger.createTimeSpan(`pull master screenshot images started`);
+
+    const masterFilePaths = (fs.readdirSync(this.masterDir)).map(f => path.join(this.masterDir, f)).filter(f => f.endsWith('.json'));
+    const masterScreenshots = masterFilePaths.map(f => JSON.parse(fs.readFileSync(f, 'utf-8')));
+    const masterImageNames = masterScreenshots.map(s => s.image);
+    const missingImages = masterImageNames.filter(masterImageName => {
+      try {
+        const masterImagePath = path.join(this.imagesDir, masterImageName);
+        fs.accessSync(masterImagePath);
+        return false;
+      } catch (e) {}
+      return true
+    });
+
+    missingImages.forEach(missingImage => {
+      const url = missingImage;
+      this.logger.info(`downloading: ${url}`);
+    });
+
+    timespan.finish(`pull master screenshot images finished`);
+  }
+
+}
+
+module.exports = LocalScreenshotConnector;