diff -r 000000000000 -r 6474c204b198 dom/bindings/parser/tests/test_unforgeable.py
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dom/bindings/parser/tests/test_unforgeable.py	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,193 @@
+def WebIDLTest(parser, harness):
+    parser.parse("""
+            interface Child : Parent {
+            };
+            interface Parent {
+              [Unforgeable] readonly attribute long foo;
+            };
+        """)
+
+    results = parser.finish()
+    harness.check(len(results), 2,
+                  "Should be able to inherit from an interface with "
+                  "[Unforgeable] properties.")
+
+    parser = parser.reset();
+    parser.parse("""
+            interface Child : Parent {
+              const short foo = 10;
+            };
+            interface Parent {
+              [Unforgeable] readonly attribute long foo;
+            };
+        """)
+
+    results = parser.finish()
+    harness.check(len(results), 2,
+                  "Should be able to inherit from an interface with "
+                  "[Unforgeable] properties even if we have a constant with "
+                  "the same name.")
+
+    parser = parser.reset();
+    parser.parse("""
+            interface Child : Parent {
+              static attribute short foo;
+            };
+            interface Parent {
+              [Unforgeable] readonly attribute long foo;
+            };
+        """)
+
+    results = parser.finish()
+    harness.check(len(results), 2,
+                  "Should be able to inherit from an interface with "
+                  "[Unforgeable] properties even if we have a static attribute "
+                  "with the same name.")
+
+    parser = parser.reset();
+    parser.parse("""
+            interface Child : Parent {
+              static void foo();
+            };
+            interface Parent {
+              [Unforgeable] readonly attribute long foo;
+            };
+        """)
+
+    results = parser.finish()
+    harness.check(len(results), 2,
+                  "Should be able to inherit from an interface with "
+                  "[Unforgeable] properties even if we have a static operation "
+                  "with the same name.")
+
+    parser = parser.reset();
+    threw = False
+    try:
+        parser.parse("""
+            interface Child : Parent {
+              void foo();
+            };
+            interface Parent {
+              [Unforgeable] readonly attribute long foo;
+            };
+        """)
+
+        results = parser.finish()
+    except:
+        threw = True
+    harness.ok(threw,
+               "Should have thrown when shadowing unforgeable attribute on "
+               "parent with operation.")
+
+    parser = parser.reset();
+    threw = False
+    try:
+        parser.parse("""
+            interface Child : Parent {
+              attribute short foo;
+            };
+            interface Parent {
+              [Unforgeable] readonly attribute long foo;
+            };
+        """)
+
+        results = parser.finish()
+    except Exception,x:
+        threw = True
+    harness.ok(threw,
+               "Should have thrown when shadowing unforgeable attribute on "
+               "parent with attribute.")
+
+    parser = parser.reset();
+    parser.parse("""
+            interface Child : Parent {
+            };
+            interface Parent {};
+            interface Consequential {
+              [Unforgeable] readonly attribute long foo;
+            };
+            Parent implements Consequential;
+        """)
+
+    results = parser.finish()
+    harness.check(len(results), 4,
+                  "Should be able to inherit from an interface with a "
+                  "consequential interface with [Unforgeable] properties.")
+
+    parser = parser.reset();
+    threw = False
+    try:
+        parser.parse("""
+            interface Child : Parent {
+              void foo();
+            };
+            interface Parent {};
+            interface Consequential {
+              [Unforgeable] readonly attribute long foo;
+            };
+            Parent implements Consequential;
+        """)
+
+        results = parser.finish()
+    except:
+        threw = True
+
+    harness.ok(threw,
+               "Should have thrown when shadowing unforgeable attribute "
+               "of parent's consequential interface.")
+
+    parser = parser.reset();
+    threw = False
+    try:
+        parser.parse("""
+            interface Child : Parent {
+            };
+            interface Parent : GrandParent {};
+            interface GrandParent {};
+            interface Consequential {
+              [Unforgeable] readonly attribute long foo;
+            };
+            GrandParent implements Consequential;
+            interface ChildConsequential {
+              void foo();
+            };
+            Child implements ChildConsequential;
+        """)
+
+        results = parser.finish()
+    except:
+        threw = True
+
+    harness.ok(threw,
+               "Should have thrown when our consequential interface shadows unforgeable attribute "
+               "of ancestor's consequential interface.")
+
+    parser = parser.reset();
+    threw = False
+    try:
+        parser.parse("""
+            interface iface {
+              [Unforgeable] attribute long foo;
+            };
+        """)
+
+        results = parser.finish()
+    except:
+        threw = True
+
+    harness.ok(threw, "Should have thrown for writable [Unforgeable] attribute.")
+
+    parser = parser.reset();
+    threw = False
+    try:
+        parser.parse("""
+            interface iface {
+              [Unforgeable] static readonly attribute long foo;
+            };
+        """)
+
+        results = parser.finish()
+    except:
+        threw = True
+
+    harness.ok(threw, "Should have thrown for static [Unforgeable] attribute.")