Add okhttp request logging in tests

dd-java-agent/testing/src/main/groovy/datadog/trace/agent/test/utils/OkHttpUtils.java

@@ -2,6 +2,10 @@ package datadog.trace.agent.test.utils;
 
 import java.util.concurrent.TimeUnit;
 import okhttp3.OkHttpClient;
+import okhttp3.logging.HttpLoggingInterceptor;
+import okhttp3.logging.HttpLoggingInterceptor.Level;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 /**
  * This class was moved from groovy to java because groovy kept trying to introspect on the
@@ -9,9 +13,29 @@ import okhttp3.OkHttpClient;
  */
 public class OkHttpUtils {
 
+  private static final Logger CLIENT_LOGGER = LoggerFactory.getLogger("http-client");
+
+  static {
+    ((ch.qos.logback.classic.Logger) CLIENT_LOGGER).setLevel(ch.qos.logback.classic.Level.DEBUG);
+  }
+
+  private static final HttpLoggingInterceptor LOGGING_INTERCEPTOR =
+      new HttpLoggingInterceptor(
+          new HttpLoggingInterceptor.Logger() {
+            @Override
+            public void log(final String message) {
+              CLIENT_LOGGER.debug(message);
+            }
+          });
+
+  static {
+    LOGGING_INTERCEPTOR.setLevel(Level.BASIC);
+  }
+
   static OkHttpClient.Builder clientBuilder() {
     final TimeUnit unit = TimeUnit.MINUTES;
     return new OkHttpClient.Builder()
+        .addInterceptor(LOGGING_INTERCEPTOR)
         .connectTimeout(1, unit)
         .writeTimeout(1, unit)
         .readTimeout(1, unit);

dd-java-agent/testing/testing.gradle

@@ -22,6 +22,7 @@ dependencies {
   compile deps.guava
 
   compile group: 'org.eclipse.jetty', name: 'jetty-server', version: '8.0.0.v20110901'
+  compile group: 'com.squareup.okhttp3', name: 'logging-interceptor', version: versions.okhttp
 
   compile project(':dd-java-agent:agent-tooling')
   compile project(':utils:test-utils')