1 files changed, 93 insertions, 0 deletions
diff --git a/devtools/client/shared/test/browser_layoutHelpers.js b/devtools/client/shared/test/browser_layoutHelpers.js
new file mode 100644
index 000000000..3274ad686
--- /dev/null
+++ b/devtools/client/shared/test/browser_layoutHelpers.js
@@ -0,0 +1,93 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+// Tests that scrollIntoViewIfNeeded works properly.
+const {scrollIntoViewIfNeeded} = require("devtools/client/shared/scroll");
+
+const TEST_URI = TEST_URI_ROOT + "browser_layoutHelpers.html";
+
+add_task(function* () {
+  let [host, win] = yield createHost("bottom", TEST_URI);
+  runTest(win);
+  host.destroy();
+});
+
+function runTest(win) {
+  let some = win.document.getElementById("some");
+
+  some.style.top = win.innerHeight + "px";
+  some.style.left = win.innerWidth + "px";
+  // The tests start with a black 2x2 pixels square below bottom right.
+  // Do not resize the window during the tests.
+
+  let xPos = Math.floor(win.innerWidth / 2);
+  // Above the viewport.
+  win.scroll(xPos, win.innerHeight + 2);
+  scrollIntoViewIfNeeded(some);
+  is(win.scrollY, Math.floor(win.innerHeight / 2) + 1,
+     "Element completely hidden above should appear centered.");
+  is(win.scrollX, xPos,
+     "scrollX position has not changed.");
+
+  // On the top edge.
+  win.scroll(win.innerWidth / 2, win.innerHeight + 1);
+  scrollIntoViewIfNeeded(some);
+  is(win.scrollY, win.innerHeight,
+     "Element partially visible above should appear above.");
+  is(win.scrollX, xPos,
+     "scrollX position has not changed.");
+
+  // Just below the viewport.
+  win.scroll(win.innerWidth / 2, 0);
+  scrollIntoViewIfNeeded(some);
+  is(win.scrollY, Math.floor(win.innerHeight / 2) + 1,
+     "Element completely hidden below should appear centered.");
+  is(win.scrollX, xPos,
+     "scrollX position has not changed.");
+
+  // On the bottom edge.
+  win.scroll(win.innerWidth / 2, 1);
+  scrollIntoViewIfNeeded(some);
+  is(win.scrollY, 2,
+     "Element partially visible below should appear below.");
+  is(win.scrollX, xPos,
+     "scrollX position has not changed.");
+
+  // Above the viewport.
+  win.scroll(win.innerWidth / 2, win.innerHeight + 2);
+  scrollIntoViewIfNeeded(some, false);
+  is(win.scrollY, win.innerHeight,
+     "Element completely hidden above should appear above " +
+     "if parameter is false.");
+  is(win.scrollX, xPos,
+     "scrollX position has not changed.");
+
+  // On the top edge.
+  win.scroll(win.innerWidth / 2, win.innerHeight + 1);
+  scrollIntoViewIfNeeded(some, false);
+  is(win.scrollY, win.innerHeight,
+     "Element partially visible above should appear above " +
+     "if parameter is false.");
+  is(win.scrollX, xPos,
+     "scrollX position has not changed.");
+
+  // Below the viewport.
+  win.scroll(win.innerWidth / 2, 0);
+  scrollIntoViewIfNeeded(some, false);
+  is(win.scrollY, 2,
+     "Element completely hidden below should appear below " +
+     "if parameter is false.");
+  is(win.scrollX, xPos,
+     "scrollX position has not changed.");
+
+  // On the bottom edge.
+  win.scroll(win.innerWidth / 2, 1);
+  scrollIntoViewIfNeeded(some, false);
+  is(win.scrollY, 2,
+     "Element partially visible below should appear below " +
+     "if parameter is false.");
+  is(win.scrollX, xPos,
+     "scrollX position has not changed.");
+}