Add billion laughs attack to test suite

Author: ashawley

jvm/src/test/scala/scala/xml/BillionLaughsAttackTest.scala

@@ -0,0 +1,36 @@
+package scala.xml
+
+import org.junit.Test
+
+class BillionLaughsAttackTest {
+
+  /**
+   * org.xml.sax.SAXParseException: JAXP00010001: The parser has
+   * encountered more than "64000" entity expansions in this document;
+   * this is the limit imposed by the JDK.
+   */
+  @Test(expected=classOf[org.xml.sax.SAXParseException])
+  def lolzTest: Unit = {
+    XML.loadString(lolz)
+  }
+
+  // Copied from https://msdn.microsoft.com/en-us/magazine/ee335713.aspx
+  val lolz =
+    """<?xml version="1.0"?>
+      |<!DOCTYPE lolz [
+      | <!ENTITY lol "lol">
+      | <!ELEMENT lolz (#PCDATA)>
+      | <!ENTITY lol1 "&lol;&lol;&lol;&lol;&lol;&lol;&lol;&lol;&lol;&lol;">
+      | <!ENTITY lol2 "&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;">
+      | <!ENTITY lol3 "&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;">
+      | <!ENTITY lol4 "&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;">
+      | <!ENTITY lol5 "&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;">
+      | <!ENTITY lol6 "&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;">
+      | <!ENTITY lol7 "&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;">
+      | <!ENTITY lol8 "&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;">
+      | <!ENTITY lol9 "&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;">
+      |]>
+      |<lolz>&lol9;</lolz>
+      |""".stripMargin
+
+}