add unit test

@@ -36,3 +36,30 @@ test('test normal send message', t => {
     });
 
 });
+
+
+test('test normal send message immediately', t => {
+    const sender = new Sender({
+        host: 'localhost',
+        port: 3003,
+        db: 'test',
+        measurement: 'test2',
+        immediate: true
+    });
+
+    sender.addMessage({
+        tags: {
+            a: 'a',
+            b: 'b'
+        },
+        fields: {
+            a: 'a',
+            b: 'b'
+        }
+    });
+
+    sender.on('ok', code => {
+        t.is(code, 204);
+    });
+
+});