diff --git a/tests/test-arg-parser.cpp b/tests/test-arg-parser.cpp
index ee13a3e5cb..8931e3b1de 100644
--- a/tests/test-arg-parser.cpp
+++ b/tests/test-arg-parser.cpp
@@ -98,10 +98,8 @@ int main(void) {
     argv = {"binary_name", "--draft", "123"};
     assert(false == common_params_parse(argv.size(), list_str_to_char(argv).data(), params, LLAMA_EXAMPLE_EMBEDDING));
 
-    // negated arg
-    // argv = {"binary_name", "--no-mmap"};
-    // assert(false == common_params_parse(argv.size(), list_str_to_char(argv).data(), params, LLAMA_EXAMPLE_COMMON));
-
+    argv = {"binary_name", "-lm", "hello"};
+    assert(false == common_params_parse(argv.size(), list_str_to_char(argv).data(), params, LLAMA_EXAMPLE_COMMON));
 
     printf("test-arg-parser: test valid usage\n\n");
 
@@ -128,6 +126,22 @@ int main(void) {
     assert(true == common_params_parse(argv.size(), list_str_to_char(argv).data(), params, LLAMA_EXAMPLE_SPECULATIVE));
     assert(params.speculative.n_max == 123);
 
+    argv = {"binary_name", "-lm", "none"};
+    assert(true == common_params_parse(argv.size(), list_str_to_char(argv).data(), params, LLAMA_EXAMPLE_COMMON));
+    assert(params.load_mode == LLAMA_LOAD_MODE_NONE);
+
+    argv = {"binary_name", "-lm", "mmap"};
+    assert(true == common_params_parse(argv.size(), list_str_to_char(argv).data(), params, LLAMA_EXAMPLE_COMMON));
+    assert(params.load_mode == LLAMA_LOAD_MODE_MMAP);
+
+    argv = {"binary_name", "-lm", "mlock"};
+    assert(true == common_params_parse(argv.size(), list_str_to_char(argv).data(), params, LLAMA_EXAMPLE_COMMON));
+    assert(params.load_mode == LLAMA_LOAD_MODE_MLOCK);
+
+    argv = {"binary_name", "-lm", "dio"};
+    assert(true == common_params_parse(argv.size(), list_str_to_char(argv).data(), params, LLAMA_EXAMPLE_COMMON));
+    assert(params.load_mode == LLAMA_LOAD_MODE_DIRECT_IO);
+
     // multi-value args (CSV)
     argv = {"binary_name", "--lora", "file1.gguf,\"file2,2.gguf\",\"file3\"\"3\"\".gguf\",file4\".gguf"};
     assert(true == common_params_parse(argv.size(), list_str_to_char(argv).data(), params, LLAMA_EXAMPLE_COMMON));
@@ -154,7 +168,9 @@ int main(void) {
     assert(params.model.path == "blah.gguf");
     assert(params.cpuparams.n_threads == 1010);
 
-    printf("test-arg-parser: test negated environment variables\n\n");
+    setenv("LLAMA_ARG_LOAD_MODE", "blah", true);
+    argv = {"binary_name"};
+    assert(false == common_params_parse(argv.size(), list_str_to_char(argv).data(), params, LLAMA_EXAMPLE_COMMON));
 
     setenv("LLAMA_ARG_LOAD_MODE", "none", true);
     argv = {"binary_name"};
@@ -178,12 +194,14 @@ int main(void) {
     assert(true == common_params_parse(argv.size(), list_str_to_char(argv).data(), params, LLAMA_EXAMPLE_COMMON));
     assert(params.load_mode == LLAMA_LOAD_MODE_DIRECT_IO);
 
-    // setenv("LLAMA_ARG_MMAP", "0", true);
-    // setenv("LLAMA_ARG_NO_PERF", "1", true); // legacy format
-    // argv = {"binary_name"};
-    // assert(true == common_params_parse(argv.size(), list_str_to_char(argv).data(), params, LLAMA_EXAMPLE_COMMON));
-    // assert(params.use_mmap == false);
-    // assert(params.no_perf == true);
+    printf("test-arg-parser: test negated environment variables\n\n");
+
+    setenv("LLAMA_ARG_LOAD_MODE", "none", true);
+    setenv("LLAMA_ARG_NO_PERF", "1", true); // legacy format
+    argv = {"binary_name"};
+    assert(true == common_params_parse(argv.size(), list_str_to_char(argv).data(), params, LLAMA_EXAMPLE_COMMON));
+    assert(params.load_mode == LLAMA_LOAD_MODE_NONE);
+    assert(params.no_perf == true);
 
     printf("test-arg-parser: test environment variables being overwritten\n\n");