1 files changed, 37 insertions, 0 deletions

diff --git a/tests/lstrlib.js b/tests/lstrlib.js
index 494b881..7120525 100644
--- a/tests/lstrlib.js
+++ b/tests/lstrlib.js
@@ -78,4 +78,41 @@ test('string.char', function (t) {
         "hello",
         "Correct element(s) on the stack"
     );
+});
+
+
+test('string.upper, string.lower', function (t) {
+    let luaCode = `
+        return string.upper("hello"), string.lower("HELLO")
+    `, L;
+    
+    t.plan(4);
+
+    t.doesNotThrow(function () {
+
+        L = lauxlib.luaL_newstate();
+
+        linit.luaL_openlibs(L);
+
+        lauxlib.luaL_loadstring(L, luaCode);
+
+    }, "Lua program loaded without error");
+
+    t.doesNotThrow(function () {
+
+        lapi.lua_call(L, 0, -1);
+
+    }, "Lua program ran without error");
+
+    t.strictEqual(
+        lapi.lua_tostring(L, -2),
+        "HELLO",
+        "Correct element(s) on the stack"
+    );
+
+    t.strictEqual(
+        lapi.lua_tostring(L, -1),
+        "hello",
+        "Correct element(s) on the stack"
+    );
 });
\ No newline at end of file