diff --git a/test/mocks/test-mocks_SerialMock.hpp b/test/mocks/test-mocks_SerialMock.hpp
index 8bd0999..7855121 100644
--- a/test/mocks/test-mocks_SerialMock.hpp
+++ b/test/mocks/test-mocks_SerialMock.hpp
@@ -116,7 +116,7 @@ void SerialMock<BufferSize>::begin(int inBaudrate)
 template<int BufferSize>
 int SerialMock<BufferSize>::available() const
 {
-    return mRxBuffer.getSize();
+    return mRxBuffer.getLength();
 }
 
 template<int BufferSize>