add no_std test

tests/no_std.rs

@@ -0,0 +1,27 @@
+#![no_std]
+#![allow(dead_code)]
+
+use auto_impl::auto_impl;
+
+mod core {}
+
+mod alloc {}
+
+struct Box;
+struct Rc;
+struct Arc;
+struct Fn;
+struct FnMut;
+
+#[auto_impl(&, &mut, Box, Rc, Arc)]
+trait Test {}
+
+#[auto_impl(Fn)]
+trait TestFn {
+    fn test(&self);
+}
+
+#[auto_impl(FnMut)]
+trait TestFnMut {
+    fn test(&mut self);
+}