IntersectionObserver: second cut.

third_party/WebKit/LayoutTests/intersection-observer/helper-functions.js

Index: third_party/WebKit/LayoutTests/intersection-observer/helper-functions.js
diff --git a/third_party/WebKit/LayoutTests/intersection-observer/helper-functions.js b/third_party/WebKit/LayoutTests/intersection-observer/helper-functions.js
new file mode 100644
index 0000000000000000000000000000000000000000..9b7cf243fbe894f5cfb6936d17f537df31a9bc34
--- /dev/null
+++ b/third_party/WebKit/LayoutTests/intersection-observer/helper-functions.js
@@ -0,0 +1,66 @@
+// Some of the js-test.js boilerplate will add stuff to the top of the document early
+// enough to screw with frame offsets that are measured by the test.  Delay all that

[esprehn, 2015/12/12 00:14:12]

hmmm...

+// jazz until the actual test code is finished.
+setPrintTestResultsLazily();
+var delayDescription = description;
+var descriptionString = "";
+var delayIsSuccessfullyParsed = isSuccessfullyParsed;
+var isSuccessfullyParsed = function() {}
+var description = function(msg) { descriptionString = msg }
+
+if (window.testRunner)
+  testRunner.waitUntilDone();
+
+function rectToString(rect) {
+  return "[" + rect.left + ", " + rect.right + ", " + rect.top + ", " + rect.bottom + "]";
+}
+
+function entryToString(entry) {
+  var ratio = ((entry.intersectionRect.width * entry.intersectionRect.height) /
+               (entry.boundingClientRect.width * entry.boundingClientRect.height));
+  return (
+      "boundingClientRect=" + rectToString(entry.boundingClientRect) +
+      "\nintersectionRect=" + rectToString(entry.intersectionRect) +

[esprehn, 2015/12/12 00:14:12]

I'd put each of these on a line, and put a separate "\n" so the "foo=" blocks
line up

[szager1, 2015/12/16 19:15:33]

Done.

+      "\nvisibleRatio=" + ratio +
+      "\nrootBounds=" + rectToString(entry.rootBounds) +
+      "\ntarget=" + entry.target +
+      "\ntime=" + entry.time);
+}
+
+function finishTest() {
+  if (descriptionString)
+    delayDescription(descriptionString);
+  delayIsSuccessfullyParsed();
+  finishJSTest();
+  if (window.testRunner)
+    testRunner.notifyDone();
+}
+
+function rectToString(rect) {

[esprehn, 2015/12/12 00:14:12]

defined twice in this file

[szager1, 2015/12/16 19:15:33]

Fixed.

+  return "[" + rect.left + ", " + rect.right + ", " + rect.top + ", " + rect.bottom + "]";
+}
+
+function checkRect(expected, actual) {
+  shouldBeEqualToNumber(actual + ".left", expected[0]);
+  shouldBeEqualToNumber(actual + ".right", expected[1]);
+  shouldBeEqualToNumber(actual + ".top", expected[2]);
+  shouldBeEqualToNumber(actual + ".bottom", expected[3]);
+}
+
+function checkEntry(expected, actual) {
+  checkRect(expected['boundingClientRect'], actual + ".boundingClientRect");

[esprehn, 2015/12/12 00:14:12]

.boundingClientRect, why the backets?

[szager1, 2015/12/16 19:15:33]

Fixed.

+  checkRect(expected['intersectionRect'], actual + ".intersectionRect");

[esprehn, 2015/12/12 00:14:12]

ditto, why the brackets?

[szager1, 2015/12/16 19:15:33]

Fixed.

+  checkRect(expected['rootBounds'], actual + ".rootBounds");
+  var actual_target = eval(actual + ".target");

[esprehn, 2015/12/12 00:14:12]

can we avoid this eval and just list all the right asserts instead?

[szager1, 2015/12/16 19:15:33]

Added a method to js-test.js to avoid doing the eval here.

+  if (isResultCorrect(actual_target, expected['target']))
+    testPassed(actual + ".target is " + expected);
+  else
+    testFailed(actual + ".target should be " + stringify(expected) + ". Was " + actual_target + ".");
+}
+
+function checkResults(expected, actual, startFrom = 0) {
+  shouldBeEqualToNumber(actual + ".length", expected.length);
+  var max = Math.min(eval(actual + ".length"), expected.length);

[esprehn, 2015/12/12 00:14:12]

don't eval, the test should contain the statements, this test is pretty hard to
debug, can you just inline what you expect? I know that might be verbose but
it's better than generating a bunch of code like this. It tends to be super hard
to debug later.

[szager1, 2015/12/16 19:15:33]

Done.

+  for (var i = startFrom; i < max; i++)
+    checkEntry(expected[i], actual + "[" + i + "]");
+}