Align tables in "ls -f" (#2105)

* Stuff column with nothing if we have nothing

* Stuff columns at the very start

Remove unnecessary else clauses.
Add the unix cfg portion

* Added some tests and cfg windows

Not sure how I feel about these tests but it's better than nothing

crates/nu-cli/tests/commands/ls.rs

@@ -1,5 +1,5 @@
 use nu_test_support::fs::Stub::EmptyFile;
-use nu_test_support::playground::Playground;
+use nu_test_support::playground::{Dirs, Playground};
 use nu_test_support::{nu, pipeline};
 
 #[test]
@@ -154,3 +154,60 @@ fn list_files_from_two_parents_up_using_multiple_dots() {
         assert_eq!(actual.out, "5");
     })
 }
+
+#[test]
+fn list_all_columns() {
+    Playground::setup(
+        "ls_test_all_columns",
+        |dirs: Dirs, sandbox: &mut Playground| {
+            sandbox.with_files(vec![
+                EmptyFile("Leonardo.yaml"),
+                EmptyFile("Raphael.json"),
+                EmptyFile("Donatello.xml"),
+                EmptyFile("Michelangelo.txt"),
+            ]);
+            // Normal Operation
+            let actual = nu!(
+                cwd: dirs.test(),
+                "ls | get | to md"
+            );
+            let expected = ["name", "type", "size", "modified"].join("");
+            assert_eq!(actual.out, expected, "column names are incorrect for ls");
+            // Symbolic Links
+            let actual = nu!(
+                cwd: dirs.test(),
+                "ls -w | get | to md"
+            );
+            let expected = ["name", "type", "target", "size", "modified"].join("");
+            assert_eq!(actual.out, expected, "column names are incorrect for ls -w");
+            // Full
+            let actual = nu!(
+                cwd: dirs.test(),
+                "ls -f | get | to md"
+            );
+            let expected = {
+                #[cfg(unix)]
+                {
+                    [
+                        "name", "type", "target", "readonly", "mode", "uid", "group", "size",
+                        "created", "accessed", "modified",
+                    ]
+                    .join("")
+                }
+
+                #[cfg(windows)]
+                {
+                    [
+                        "name", "type", "target", "readonly", "size", "created", "accessed",
+                        "modified",
+                    ]
+                    .join("")
+                }
+            };
+            assert_eq!(
+                actual.out, expected,
+                "column names are incorrect for ls full"
+            );
+        },
+    );
+}