Output test progress log for Travis CI.

library/build.gradle

@@ -50,6 +50,18 @@ android {
     }
 }
 
+// When testing on Travis CI,
+// connectedCheck task doesn't output logs for more than 10 minutes often,
+// which causes build failure.
+// To avoid this, we change the log level for test tasks.
+// Test tasks for buildTypes will be defined on evaluation phase,
+// so do it on afterEvaluate.
+afterEvaluate { project ->
+    tasks.withType(VerificationTask) {
+        logging.level = LogLevel.INFO
+    }
+}
+
 apply plugin: 'com.github.kt3k.coveralls'
 
 coveralls.jacocoReportPath = 'build/reports/coverage/debug/report.xml'