diff --git a/tests/test_use_nix.py b/tests/test_use_nix.py
new file mode 100644
index 0000000..98cb351
--- /dev/null
+++ b/tests/test_use_nix.py
@@ -0,0 +1,37 @@
+#!/usr/bin/env python2
+
+import sys
+import subprocess
+import unittest
+
+from procs import run
+from direnv_project import DirenvProject
+
+
+def direnv_exec(direnv_project: DirenvProject, cmd: str) -> None:
+    out = run(
+        ["direnv", "exec", str(direnv_project.dir), "sh", "-c", cmd],
+        stderr=subprocess.PIPE,
+        stdout=subprocess.PIPE,
+        check=False,
+        cwd=direnv_project.dir,
+    )
+    sys.stdout.write(out.stdout)
+    sys.stderr.write(out.stderr)
+    assert out.returncode == 0
+    assert "OK\n" == out.stdout
+    assert "renewed cache" in out.stderr
+
+
+def test_attrs(direnv_project: DirenvProject) -> None:
+    direnv_project.setup_envrc("use nix -A subshell")
+    direnv_exec(direnv_project, "echo $THIS_IS_A_SUBSHELL")
+
+
+def test_args(direnv_project: DirenvProject) -> None:
+    direnv_project.setup_envrc("use nix --argstr someArg OK")
+    direnv_exec(direnv_project, "echo $SHOULD_BE_SET")
+
+
+if __name__ == "__main__":
+    unittest.main()
diff --git a/tests/testenv/shell.nix b/tests/testenv/shell.nix
index 55be618..c5c9d85 100644
--- a/tests/testenv/shell.nix
+++ b/tests/testenv/shell.nix
@@ -1,7 +1,14 @@
-{ pkgs ? import <nixpkgs> {} }:
+{ pkgs ? import <nixpkgs> {}, someArg ? null }:
 pkgs.mkShellNoCC {
   nativeBuildInputs = [ pkgs.hello ];
   shellHook = ''
     echo "Executing shellHook."
   '';
+  SHOULD_BE_SET = someArg;
+
+  passthru = {
+    subshell = pkgs.mkShellNoCC {
+      THIS_IS_A_SUBSHELL = "OK";
+    };
+  };
 }