Implemented an abstraction for extracting flags from builtins

src/tests/getopt.rs

@@ -0,0 +1,37 @@
+use getopt::get_opts_from_tokens;
+use parse::NdRule;
+use tests::get_nodes;
+
+use super::super::*;
+
+#[test]
+fn getopt_from_argv() {
+	let node = get_nodes("echo -n -e foo", |node| matches!(node.class, NdRule::Command {..}))
+		.pop()
+		.unwrap();
+	let NdRule::Command { assignments, argv } = node.class else {
+		panic!()
+	};
+
+	let (words,opts) = get_opts_from_tokens(argv);
+	insta::assert_debug_snapshot!(words);
+	insta::assert_debug_snapshot!(opts)
+}
+
+#[test]
+fn getopt_simple() {
+	let raw = "echo -n foo".split_whitespace().map(|s| s.to_string()).collect::<Vec<_>>();
+
+	let (words,opts) = get_opts(raw);
+	insta::assert_debug_snapshot!(words);
+	insta::assert_debug_snapshot!(opts);
+}
+
+#[test]
+fn getopt_multiple_short() {
+	let raw = "echo -nre foo".split_whitespace().map(|s| s.to_string()).collect::<Vec<_>>();
+
+	let (words,opts) = get_opts(raw);
+	insta::assert_debug_snapshot!(words);
+	insta::assert_debug_snapshot!(opts);
+}