feat: add tests

__std/misc/src/bin/iff_test.rs

@@ -0,0 +1,10 @@
+use std::env::args;
+
+#[macro_export] macro_rules! iff {
+    ($c:expr, $t:expr, $f:expr) => ( if $c { $t } else { $f } )
+}
+
+fn main() {
+    let has_arg = iff!(args().skip(1).len() > 0, true, false);
+    println!("Has args: {}", has_arg);
+}