add test suite, help/exit functionality

test.nix

@@ -0,0 +1,30 @@
+{
+  lib,
+  stdenv,
+  nasm,
+  ...
+}:
+stdenv.mkDerivation {
+  name = "asm-test";
+  src = ./src;
+  nativeBuildInputs = [
+    nasm
+  ];
+  buildInputs = [
+  ];
+  configurePhase = ''
+  '';
+  buildPhase = ''
+    nasm -f elf test_start.asm
+    ld -m elf_i386 test_start.o -o test
+  '';
+  installPhase = ''
+    mkdir -p $out/bin
+    cp test $out/bin/test
+  '';
+
+  meta = {
+    license = lib.licenses.wtfpl;
+    mainProgram = "test";
+  };
+}