Prevents duplicate fields in transpose -r (#5840)

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

@@ -65,6 +65,7 @@ mod split_row;
 mod str_;
 mod take;
 mod touch;
+mod transpose;
 mod uniq;
 mod update;
 mod upsert;

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

@@ -0,0 +1,37 @@
+use nu_test_support::{nu, pipeline};
+
+#[test]
+fn row() {
+    let actual = nu!(
+    cwd: ".", pipeline(
+    r#"
+        [[key value]; [foo 1] [foo 2]] | transpose -r | debug
+            "#
+    ));
+
+    assert!(actual.out.contains("foo: 1"));
+}
+
+#[test]
+fn row_but_last() {
+    let actual = nu!(
+    cwd: ".", pipeline(
+    r#"
+        [[key value]; [foo 1] [foo 2]] | transpose -r -l | debug
+            "#
+    ));
+
+    assert!(actual.out.contains("foo: 2"));
+}
+
+#[test]
+fn row_but_all() {
+    let actual = nu!(
+    cwd: ".", pipeline(
+    r#"
+        [[key value]; [foo 1] [foo 2]] | transpose -r -a | debug
+            "#
+    ));
+
+    assert!(actual.out.contains("foo: [1, 2]"));
+}