Realign default compressable MIME types with Tomcat's defaults

Closes gh-3592

spring-boot/src/main/java/org/springframework/boot/context/embedded/Compression.java

@@ -34,7 +34,7 @@ public class Compression {
 	 * Comma-separated list of MIME types that should be compressed.
 	 */
 	private String[] mimeTypes = new String[] { "text/html", "text/xml", "text/plain",
-			"text/css" };
+			"text/css", "text/javascript", "application/javascript" };
 
 	/**
 	 * Comma-separated list of user agents for which responses should not be compressed.

spring-boot/src/test/java/org/springframework/boot/context/embedded/CompressionTests.java

@@ -0,0 +1,42 @@
+/*
+ * Copyright 2012-2016 the original author or authors.
+ *
+ * Licensed 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.springframework.boot.context.embedded;
+
+import org.apache.coyote.http11.Http11NioProtocol;
+import org.junit.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Tests for {@link Compression}.
+ *
+ * @author Andy Wilkinson
+ */
+public class CompressionTests {
+
+	@Test
+	public void defaultCompressableMimeTypesMatchesTomcatsDefault() {
+		assertThat(new Compression().getMimeTypes())
+				.containsExactlyInAnyOrder(getTomcatDefaultCompressableMimeTypes());
+	}
+
+	private String[] getTomcatDefaultCompressableMimeTypes() {
+		Http11NioProtocol protocol = new Http11NioProtocol();
+		return protocol.getCompressableMimeTypes();
+	}
+
+}