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+<!DOCTYPE html><html class="reftest-paged">
+<style>html{font-size:12pt}</style>
+<!-- http example.org uri makes this an oop if with fission -->
+<iframe style="height: 1000vh" src="http://example.org/1743533-1-helper.html">
+</iframe>
+</html>
+
+<!--
+Some notes about this test.
+To reproduce the problem we just need an oop iframe that spans multiple pages,
+and some content in it that also spans multiple pages. I used text instead
+of a background color because background colors don't show up by default in
+print preview. We're using page mode here and not print preview, so that is
+not technically required here.
+
+The most obvious way to test this would be to compare an oop iframe and an
+in process iframe with the same content to make sure they are the same.
+However, for some reason, in reftest-paged mode a simple in process iframe
+seems to refuse to load the document, I think because of this code
+https://searchfox.org/mozilla-central/rev/3c9369510cb883b9f08d5f9641e1233d2142f025/dom/base/nsFrameLoader.cpp#439
+If the same iframe is oop then the document does load, this behaviour difference
+seems like it might be a bug. If that bug is ever fixed (so that the oop iframe here fails to
+load it's document) then writing a test to exercise the original bug here seems
+like it would be impossible.
+
+So we compare an oop iframe with content in it, to a blank iframe, and then
+we use a high minimum accepted number of pixels differing in the fuzz. This
+then makes sure the two documents differ by enough pixels.
+
+And we skip running this test if fission is disabled, as that would just
+compare two blank iframes, which is not useful.
+
+note why we couldn't use other test types
+I tried to write this as a wpt print reftest, it did not reproduce the bug.
+I'm not sure what wpt reftests use to simulate printing, but I suspect it
+is not similar enough to our print preview to trigger the bug.
+
+I tried to add this as a test to layout/base/tests/chrome/test_printpreview.xhtml
+but that is not feasible because that test runs as part of the mochitest-chrome
+suite, which I'm told doesn't even run in e10s mode, and definitely does not get
+run with fission, which is required to reproduce the bug.
+-->