diff --git a/build.gradle b/build.gradle
index a1c030da..1c867e49 100644
--- a/build.gradle
+++ b/build.gradle
@@ -69,7 +69,8 @@ dependencies {
     optional 'com.squareup.okhttp:okhttp:2.2.0'
     
     // SLF4J logging API
-    compile 'org.slf4j:slf4j-simple:1.7.7'
+    compile 'org.slf4j:slf4j-api:1.7.7'
+    testRuntime 'org.slf4j:slf4j-simple:1.7.7'
 
     // Jackson JSON processor
     compile 'com.fasterxml.jackson.core:jackson-databind:2.4.1.1'