Command tests (#922)

* WIP command tests

* Finish marking todo tests

* update

* update

* Windows cd test ignoring

crates/nu-command/tests/commands/help.rs

@@ -0,0 +1,33 @@
+use nu_test_support::{nu, pipeline};
+
+#[test]
+fn help_commands_length() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+        help commands | length
+        "#
+    ));
+
+    let output = actual.out;
+    let output_int: i32 = output.parse().unwrap();
+    let is_positive = output_int.is_positive();
+    assert!(is_positive);
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn help_generate_docs_length() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+        help generate_docs | flatten | length
+        "#
+    ));
+
+    let output = actual.out;
+    let output_int: i32 = output.parse().unwrap();
+    let is_positive = output_int.is_positive();
+    assert!(is_positive);
+}