Command tests (#922)

* WIP command tests

* Finish marking todo tests

* update

* update

* Windows cd test ignoring

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

@@ -0,0 +1,35 @@
+use nu_test_support::{nu, pipeline};
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn headers_uses_first_row_as_header() {
+    let actual = nu!(
+    cwd: "tests/fixtures/formats", pipeline(
+        r#"
+            open sample_headers.xlsx
+            | get Sheet1
+            | headers
+            | get header0
+            | from json"#
+    ));
+
+    assert_eq!(actual.out, "r1c0r2c0")
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn headers_adds_missing_column_name() {
+    let actual = nu!(
+    cwd: "tests/fixtures/formats", pipeline(
+        r#"
+            open sample_headers.xlsx
+            | get Sheet1
+            | headers
+            | get Column1
+            | from json"#
+    ));
+
+    assert_eq!(actual.out, "r1c1r2c1")
+}