Command tests (#922)

* WIP command tests

* Finish marking todo tests

* update

* update

* Windows cd test ignoring

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

@@ -0,0 +1,61 @@
+use nu_test_support::{nu, pipeline};
+
+#[test]
+fn echo_range_is_lazy() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+        echo 1..10000000000 | first 3 | to json --raw
+        "#
+    ));
+
+    assert_eq!(actual.out, "[1,2,3]");
+}
+
+#[test]
+fn echo_range_handles_inclusive() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+        echo 1..3 | each { $it } | to json --raw
+        "#
+    ));
+
+    assert_eq!(actual.out, "[1,2,3]");
+}
+
+#[test]
+fn echo_range_handles_exclusive() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+        echo 1..<3 | each { $it } | to json --raw
+        "#
+    ));
+
+    assert_eq!(actual.out, "[1,2]");
+}
+
+#[test]
+fn echo_range_handles_inclusive_down() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+        echo 3..1 | each { $it } | to json --raw
+        "#
+    ));
+
+    assert_eq!(actual.out, "[3,2,1]");
+}
+
+#[test]
+fn echo_range_handles_exclusive_down() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+        echo 3..<1 | each { $it } | to json --raw
+        "#
+    ));
+
+    assert_eq!(actual.out, "[3,2]");
+}