1 files changed, 90 insertions, 0 deletions
diff --git a/browser/components/newtab/tests/browser/browser_PreviewProvider.js b/browser/components/newtab/tests/browser/browser_PreviewProvider.js
new file mode 100644
index 000000000..b1e3eda9f
--- /dev/null
+++ b/browser/components/newtab/tests/browser/browser_PreviewProvider.js
@@ -0,0 +1,90 @@
+/* globals XPCOMUtils, Services, PreviewProvider, registerCleanupFunction */
+"use strict";
+
+let Cu = Components.utils;
+Cu.import("resource://gre/modules/Task.jsm");
+Cu.import("resource://gre/modules/XPCOMUtils.jsm");
+Cu.import("resource://gre/modules/Services.jsm");
+
+XPCOMUtils.defineLazyModuleGetter(this, "PreviewProvider",
+                                  "resource:///modules/PreviewProvider.jsm");
+
+var oldEnabledPref = Services.prefs.getBoolPref("browser.pagethumbnails.capturing_disabled");
+Services.prefs.setBoolPref("browser.pagethumbnails.capturing_disabled", false);
+
+registerCleanupFunction(function() {
+  while (gBrowser.tabs.length > 1) {
+    gBrowser.removeTab(gBrowser.tabs[1]);
+  }
+  Services.prefs.setBoolPref("browser.pagethumbnails.capturing_disabled", oldEnabledPref);
+});
+
+const TEST_URL = "https://example.com/browser/browser/components/newtab/tests/browser/blue_page.html";
+
+function pixelsForDataURI(dataURI, options) {
+  return new Promise(resolve => {
+    if (!options) {
+      options = {};
+    }
+    let {width, height} = options;
+    if (!width) {
+      width = 100;
+    }
+    if (!height) {
+      height = 100;
+    }
+
+    let htmlns = "http://www.w3.org/1999/xhtml";
+    let img = document.createElementNS(htmlns, "img");
+    img.setAttribute("src", dataURI);
+
+    img.addEventListener("load", function onLoad() {
+      img.removeEventListener("load", onLoad, true);
+      let canvas = document.createElementNS(htmlns, "canvas");
+      canvas.setAttribute("width", width);
+      canvas.setAttribute("height", height);
+      let ctx = canvas.getContext("2d");
+      ctx.drawImage(img, 0, 0, width, height);
+      let result = ctx.getImageData(0, 0, width, height).data;
+      resolve(result);
+    });
+  });
+}
+
+function* chunk_four(listData) {
+  let index = 0;
+  while (index < listData.length) {
+    yield listData.slice(index, index + 5);
+    index += 4;
+  }
+}
+
+add_task(function* open_page() {
+  let dataURI = yield PreviewProvider.getThumbnail(TEST_URL);
+  let pixels = yield pixelsForDataURI(dataURI, {width: 10, height: 10});
+  let rgbCount = {r: 0, g: 0, b: 0, a: 0};
+  for (let [r, g, b, a] of chunk_four(pixels)) {
+    if (r === 255) {
+      rgbCount.r += 1;
+    }
+    if (g === 255) {
+      rgbCount.g += 1;
+    }
+    if (b === 255) {
+      rgbCount.b += 1;
+    }
+    if (a === 255) {
+      rgbCount.a += 1;
+    }
+  }
+  Assert.equal(`${rgbCount.r},${rgbCount.g},${rgbCount.b},${rgbCount.a}`,
+      "0,0,100,100", "there should be 100 blue-only pixels at full opacity");
+});
+
+add_task(function* invalid_url() {
+  try {
+    yield PreviewProvider.getThumbnail("invalid:URL");
+  } catch (err) {
+    Assert.ok(true, "URL Failed");
+  }
+});