diff --git a/ChangeLog b/ChangeLog
index ac533530..3eb6ad01 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2009-05-12  Tatsuhiro Tsujikawa  <t-tujikawa@users.sourceforge.net>
+
+	Added test case for zero-length filter.
+	* test/BitfieldManTest.cc
+
 2009-05-12  Tatsuhiro Tsujikawa  <t-tujikawa@users.sourceforge.net>
 
 	getFiles command now returns file data for finished/stopped
diff --git a/test/BitfieldManTest.cc b/test/BitfieldManTest.cc
index 0acd76ea..2b7f2f9d 100644
--- a/test/BitfieldManTest.cc
+++ b/test/BitfieldManTest.cc
@@ -33,6 +33,7 @@ class BitfieldManTest:public CppUnit::TestFixture {
   CPPUNIT_TEST(testGetMissingUnusedIndex_noarg);
   CPPUNIT_TEST(testCountFilteredBlock);
   CPPUNIT_TEST(testCountMissingBlock);
+  CPPUNIT_TEST(testZeroLengthFilter);
   CPPUNIT_TEST_SUITE_END();
 private:
   SharedHandle<Randomizer> fixedNumberRandomizer;
@@ -69,6 +70,7 @@ public:
   void testSetBitRange();
   void testCountFilteredBlock();
   void testCountMissingBlock();
+  void testZeroLengthFilter();
 };
 
 
@@ -771,4 +773,11 @@ void BitfieldManTest::testCountMissingBlock()
   CPPUNIT_ASSERT_EQUAL((size_t)0, bt.countMissingBlock());
 }
 
+void BitfieldManTest::testZeroLengthFilter()
+{
+  BitfieldMan bt(1024, 1024*10);
+  bt.enableFilter();
+  CPPUNIT_ASSERT_EQUAL((size_t)0, bt.countMissingBlock());
+}
+
 } // namespace aria2