Add test case

.travis.yml

@@ -9,6 +9,6 @@ before_install:
 
 install:
   - jdk_switcher use oraclejdk8
-  - mvn clean install --quiet jacoco:report coveralls:report -X
+  - mvn clean install --quiet jacoco:report coveralls:report
   - mvn clean javadoc:javadoc -Dmaven.test.skip=true --quiet
 

apm-webapp/src/test/java/org/apache/skywalking/apm/webapp/tools/RewritePathFilterTest.java

@@ -0,0 +1,60 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package org.apache.skywalking.apm.webapp.tools;
+
+import com.netflix.zuul.context.RequestContext;
+import org.junit.Before;
+import org.junit.Test;
+
+import static org.hamcrest.core.Is.is;
+import static org.junit.Assert.*;
+import static org.springframework.cloud.netflix.zuul.filters.support.FilterConstants.PRE_DECORATION_FILTER_ORDER;
+
+public class RewritePathFilterTest {
+
+    private RewritePathFilter filter;
+
+    @Before
+    public void init() {
+        filter = new RewritePathFilter("/graphql");
+    }
+
+    @Test
+    public void filterOrder() {
+        assertThat(filter.filterOrder(), is(PRE_DECORATION_FILTER_ORDER + 1));
+    }
+
+    @Test
+    public void filterType() {
+        assertThat(filter.filterType(), is("pre"));
+    }
+
+    @Test
+    public void shouldFilter() {
+        assertFalse(filter.shouldFilter());
+        RequestContext.getCurrentContext().set("requestURI");
+        assertTrue(filter.shouldFilter());
+    }
+
+    @Test
+    public void run() {
+        filter.run();
+        assertThat(RequestContext.getCurrentContext().get("requestURI"), is("/graphql"));
+    }
+}