If a DRT test calls window.open(), result is
java.lang.UnsupportedOperationException: Not supported yet
       at com.sun.browser.dumprendertree.UIClientImpl.createPage(UIClientImpl.java:20)
       at com.sun.webpane.platform.WebPage.fwkCreateWindow(WebPage.java:1878)
       at com.sun.webpane.webkit.network.URLProcessor.endOfDataCallback(Native Method)
       at com.sun.webpane.webkit.network.URLProcessor.access$300(URLProcessor.java:16)
       at com.sun.webpane.webkit.network.URLProcessor$3.run(URLProcessor.java:86)
       at com.sun.browser.dumprendertree.InvokerImpl$Worker.run(InvokerImpl.java:113)
       at java.lang.Thread.run(Thread.java:662)

Examples of failing tests:
  fast/dom/Window/new-window-opener.html
  fast/dom/Window/window-open-pending-url.html
  fast/loader/stateobjects/popstate-fires-with-page-cache.html