Zero-sized new-space for VM isolate.

runtime/vm/scavenger_test.cc

Index: runtime/vm/scavenger_test.cc
===================================================================
--- runtime/vm/scavenger_test.cc	(revision 0)
+++ runtime/vm/scavenger_test.cc	(revision 0)
@@ -0,0 +1,63 @@
+// Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+#include "platform/assert.h"
+#include "vm/scavenger.h"
+#include "vm/unit_test.h"
+#include "vm/visitor.h"
+
+namespace dart {
+
+// Expects to visit no objects (since the space should be empty).
+class FailingObjectVisitor : public ObjectVisitor {
+ public:
+  FailingObjectVisitor() : ObjectVisitor(NULL) {}
+  virtual void VisitObject(RawObject* obj) {
+    EXPECT(false);
+  }
+};
+
+// Expects to visit no objects (since the space should be empty).
+class FailingObjectPointerVisitor : public ObjectPointerVisitor {
+ public:
+  FailingObjectPointerVisitor() : ObjectPointerVisitor(NULL) {}
+  virtual void VisitPointers(RawObject** first, RawObject** last) {
+    EXPECT(false);
+  }
+};
+
+// Expects to visit no objects (since the space should be empty).
+class FailingFindObjectVisitor : public FindObjectVisitor {
+ public:
+  FailingFindObjectVisitor() : FindObjectVisitor(NULL) {}
+  virtual bool FindObject(RawObject* obj) const {
+    EXPECT(false);
+    return false;
+  }
+};
+
+TEST_CASE(ZeroSizeScavenger) {
+  Scavenger* scavenger = new Scavenger(NULL, 0, kNewObjectAlignmentOffset);
+  EXPECT(!scavenger->Contains(reinterpret_cast<uword>(&scavenger)));
+  EXPECT_EQ(0, scavenger->UsedInWords());
+  EXPECT_EQ(0, scavenger->CapacityInWords());
+  EXPECT_EQ(static_cast<uword>(0), scavenger->TryAllocate(kObjectAlignment));
+  FailingObjectVisitor obj_visitor;
+  scavenger->VisitObjects(&obj_visitor);
+  FailingObjectPointerVisitor ptr_visitor;
+  scavenger->VisitObjectPointers(&ptr_visitor);
+  FailingFindObjectVisitor find_visitor;
+  scavenger->FindObject(&find_visitor);
+  delete scavenger;
+}
+
+TEST_CASE(ZeroSizeScavengerGC) {
+  // Ensure 'Scavenge' doesn't crash. We must supply an actual heap.
+  Scavenger* scavenger =
+      new Scavenger(Dart::vm_isolate()->heap(), 0, kNewObjectAlignmentOffset);
+  scavenger->Scavenge();
+  delete scavenger;
+}
+
+}  // namespace dart