diff --git a/googletest/samples/sample4_unittest.cc b/googletest/samples/sample4_unittest.cc
index fa5afc7..d5144c0 100644
--- a/googletest/samples/sample4_unittest.cc
+++ b/googletest/samples/sample4_unittest.cc
@@ -26,20 +26,28 @@
 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-//
-// Author: wan@google.com (Zhanyong Wan)
 
-#include "gtest/gtest.h"
+
 #include "sample4.h"
+#include "gtest/gtest.h"
 
+namespace {
 // Tests the Increment() method.
+
 TEST(Counter, Increment) {
   Counter c;
 
+  // Test that counter 0 returns 0
+  EXPECT_EQ(0, c.Decrement());
+
   // EXPECT_EQ() evaluates its arguments exactly once, so they
   // can have side effects.
 
   EXPECT_EQ(0, c.Increment());
   EXPECT_EQ(1, c.Increment());
   EXPECT_EQ(2, c.Increment());
+
+  EXPECT_EQ(3, c.Decrement());
 }
+
+}  // namespace