diff --git a/birch/src/test/java/com/gruffins/birch/LoggerTest.kt b/birch/src/test/java/com/gruffins/birch/LoggerTest.kt
index fd9bb85..d42e79f 100644
--- a/birch/src/test/java/com/gruffins/birch/LoggerTest.kt
+++ b/birch/src/test/java/com/gruffins/birch/LoggerTest.kt
@@ -79,7 +79,7 @@ class LoggerTest {
         agent.console = true
         logger.level = Level.TRACE
 
-        val block = spyk({ "test" })
+        val block: () -> String = spyk()
 
         logger.log(Level.TRACE, { "test" }, block)
         logger.log(Level.DEBUG, { "test" }, block)