Classes: Add more tests for prototype edge cases

test/mjsunit/harmony/classes.js

Index: test/mjsunit/harmony/classes.js
diff --git a/test/mjsunit/harmony/classes.js b/test/mjsunit/harmony/classes.js
index 3a22fd9b5427dcf74873f541744fcd65c42a7978..c44c2cdcb9a05ab229caec8949f6f71f4685594f 100644
--- a/test/mjsunit/harmony/classes.js
+++ b/test/mjsunit/harmony/classes.js
@@ -174,6 +174,7 @@ function assertMethodDescriptor(object, name) {
   assertEquals('function', typeof descr.value);
 }
 
+
 function assertGetterDescriptor(object, name) {
   var descr = Object.getOwnPropertyDescriptor(object, name);
   assertTrue(descr.configurable);
@@ -387,6 +388,56 @@ function assertAccessorDescriptor(object, name) {
   assertEquals(2, C.staticM());
 })();
 
+
+(function TestConstructableButNoPrototype() {
+  var Base = function() {}.bind();
+  assertThrows(function() {
+    class C extends Base {}
+  }, TypeError);
+})();
+
+
+(function TestPrototypeGetter() {
+  var calls = 0;
+  var Base = function() {}.bind();
+  Object.defineProperty(Base, 'prototype', {
+    get: function() {
+      calls++;
+      return null;
+    },
+    configurable: true
+  });
+  class C extends Base {}
+  assertEquals(1, calls);
+
+  calls = 0;
+  Object.defineProperty(Base, 'prototype', {
+    get: function() {
+      calls++;
+      return 42;
+    },
+    configurable: true
+  });
+  assertThrows(function() {
+    class C extends Base {}
+  }, TypeError);
+  assertEquals(1, calls);
+})();
+
+
+(function TestPrototypeSetter() {
+  var Base = function() {}.bind();
+  Object.defineProperty(Base, 'prototype', {
+    set: function() {
+      assertUnreachable();
+    }
+  });
+  assertThrows(function() {
+    class C extends Base {}
+  }, TypeError);
+})();
+
+
 /* TODO(arv): Implement
 (function TestNameBindingInConstructor() {
   class C {