diff --git a/phosphor-regulators/test/test_sdbus_error.hpp b/phosphor-regulators/test/test_sdbus_error.hpp
index a4ac9ee..09cc5f7 100644
--- a/phosphor-regulators/test/test_sdbus_error.hpp
+++ b/phosphor-regulators/test/test_sdbus_error.hpp
@@ -47,6 +47,11 @@
         return "";
     }
 
+    int get_errno() const noexcept override
+    {
+        return EIO;
+    }
+
   private:
     const std::string error{};
 };