diff --git a/tests/testthat/test_01-manipulateConfig.R b/tests/testthat/test_01-manipulateConfig.R
index 62f423970..566c5a722 100644
--- a/tests/testthat/test_01-manipulateConfig.R
+++ b/tests/testthat/test_01-manipulateConfig.R
@@ -3,6 +3,15 @@ test_that("manipulate config with default configuration does not change main.gms
   cfg_init <- gms::readDefaultConfig("../..")
   tmpfile <- tempfile(pattern = "main-TESTTHAT-", tmpdir = "../..", fileext = ".gms")
   file.copy("../../main.gms", tmpfile)
+
+  # generate arbitrary settings, manipulate file, read them again and check identity
+  cfg_new <- cfg_init
+  cfg_new$gms[names(cfg_new$gms)] <- rep(c(0, 1, "asdf", "bc3", "3bc"), length(cfg_new$gms))[1:length(cfg_new$gms)]
+  lucode2::manipulateConfig(tmpfile, cfg_new$gms)
+  cfg_new_after <- gms::readDefaultConfig("../..", basename(tmpfile))
+  expect_equal(cfg_new_after, cfg_new)
+
+  # reset to initial setting and check that nothing has changed at all in the file
   lucode2::manipulateConfig(tmpfile, cfg_init$gms)
   cfg_after <- gms::readDefaultConfig("../..", basename(tmpfile))