Add tags test case.

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());

    }

}