[2377] hide test definitions in an unnamed namespace.

src/lib/dns/tests/master_loader_unittest.cc

@@ -35,6 +35,7 @@ using std::list;
 using std::ofstream;
 using std::endl;
 
+namespace {
 class MasterLoaderTest : public ::testing::Test {
 public:
     MasterLoaderTest() :
@@ -243,3 +244,4 @@ TEST_F(MasterLoaderTest, loadTwice) {
     loader_->load();
     EXPECT_THROW(loader_->load(), isc::InvalidOperation);
 }
+}