message: Make sure a library used for testing is tagged as such.
  That way, it is not accidentally used in final binaries.
diff: @@ -185,6 +185,7 @@ cc_library(
  cc_library(
  name = "token_partition_tree_test_utils",
  + testonly = 1,
  srcs = ["token_partition_tree_test_utils.cc"],
  hdrs = ["token_partition_tree_test_utils.h"],
  deps = [
  