Add tags test case.

skywalking-commons/skywalking-trace/src/test/java/com/a/eye/skywalking/trace/tag/TagsTest.java

@@ -0,0 +1,54 @@
+package com.a.eye.skywalking.trace.tag;
+
+import com.a.eye.skywalking.trace.Span;
+import org.junit.Assert;
+import org.junit.Test;
+
+/**
+ * @author wusheng
+ */
+public class TagsTest {
+    @Test
+    public void testLayer(){
+        Span span = new Span(1, "/test");
+        Tags.SPAN_LAYER.asDB(span);
+        Assert.assertEquals("db", span.getTag("span.layer"));
+
+        Tags.SPAN_LAYER.asRPCFramework(span);
+        Assert.assertEquals("rpc", span.getTag("span.layer"));
+
+        Tags.SPAN_LAYER.asHttp(span);
+        Assert.assertEquals("http", span.getTag("span.layer"));
+    }
+
+    @Test
+    public void testBooleanTag(){
+        BooleanTag tag = new BooleanTag("test.key", false);
+        Span span = new Span(1, "/test");
+        Assert.assertFalse(tag.get(span));
+
+        tag.set(span, true);
+        Assert.assertTrue(tag.get(span));
+    }
+
+    @Test
+    public void testIntTag(){
+        IntTag tag = new IntTag("test.key");
+        Span span = new Span(1, "/test");
+        Assert.assertNull(tag.get(span));
+
+        tag.set(span, 123);
+        Assert.assertEquals(123, tag.get(span).intValue());
+    }
+
+    @Test
+    public void testShortTag(){
+        ShortTag tag = new ShortTag("test.key");
+        Span span = new Span(1, "/test");
+        Assert.assertNull(tag.get(span));
+
+        short value = 123;
+        tag.set(span, value);
+        Assert.assertEquals(value, tag.get(span).intValue());
+    }
+}