Merge pull request #678 from sharding-jdbc/dev

add test case

sharding-core/src/test/java/io/shardingjdbc/core/hint/HintManagerHolderTest.java

@@ -77,6 +77,12 @@ public final class HintManagerHolderTest {
         assertFalse(HintManagerHolder.isUseShardingHint());
     }
     
+    @Test
+    public void assertIsDatabaseShardingOnlyWithoutSet() {
+        hintManager.close();
+        assertFalse(HintManagerHolder.isDatabaseShardingOnly());
+    }
+    
     @Test
     public void assertIsMasterRouteOnly() {
         hintManager.setMasterRouteOnly();