Command tests (#922)

* WIP command tests

* Finish marking todo tests

* update

* update

* Windows cd test ignoring

crates/nu-command/tests/commands/random/mod.rs

@@ -0,0 +1,7 @@
+mod bool;
+mod chars;
+mod decimal;
+mod dice;
+mod integer;
+#[cfg(feature = "uuid_crate")]
+mod uuid;