Fix sandboxing of redirection tests (#11407)

When running `cargo test --workspace` a file `crates/nu-command/a.txt`
remained which we also saw as an accidential additions in some commits.

Searching for `a.txt` narrowed it down that
`redirection_keep_exit_codes` was not sandboxed in a temporary directory
and created this file.

Went through redirection tests and placed them in a `Playground` to get
sandboxing `dirs` for `nu!(cwd:`.
For those tests where redirection fails and no file should be created
now I added a check that no file is created on accident.


- Sandbox `redirection_keep_exit_codes` test
- Sandbox `no_duplicate_redirection` test
- Check that no redirect file is created on error
- Sandbox `redirection_should_have_a_target` test

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

@@ -161,9 +161,14 @@ fn same_target_redirection_with_too_much_stderr_not_hang_nushell() {
 
 #[test]
 fn redirection_keep_exit_codes() {
-    let out = nu!("do -i { nu --testbin fail e> a.txt } | complete | get exit_code");
+    Playground::setup("redirection preserves exit code", |dirs, _| {
+        let out = nu!(
+            cwd: dirs.test(),
+            "do -i { nu --testbin fail e> a.txt } | complete | get exit_code"
+        );
         // needs to use contains "1", because it complete will output `Some(RawStream)`.
         assert!(out.out.contains('1'));
+    });
 }
 
 #[test]
@@ -302,6 +307,7 @@ fn separate_redirection_support_variable() {
 
 #[test]
 fn redirection_should_have_a_target() {
+    Playground::setup("redirection_should_have_a_target", |dirs, _| {
         let scripts = [
             "echo asdf o+e>",
             "echo asdf o>",
@@ -313,13 +319,17 @@ fn redirection_should_have_a_target() {
             "echo asdf o>; echo asdf",
         ];
         for code in scripts {
-        let actual = nu!(code);
+            let actual = nu!(cwd: dirs.test(), code);
             assert!(
                 actual.err.contains("expected redirection target",),
-            "should be error, code: {}",
-            code
+                "should be error, code: {code}",
+            );
+            assert!(
+                !dirs.test().join("tmp.txt").exists(),
+                "No file should be created on error: {code}",
             );
         }
+    });
 }
 
 #[test]
@@ -352,8 +362,24 @@ fn redirection_with_pipe() {
 
 #[test]
 fn no_duplicate_redirection() {
-    let actual = nu!("echo 3 o> a.txt o> a.txt");
+    Playground::setup("redirection does not accept duplicate", |dirs, _| {
+        let actual = nu!(
+            cwd: dirs.test(),
+            "echo 3 o> a.txt o> a.txt"
+        );
         assert!(actual.err.contains("Redirection can be set only once"));
-    let actual = nu!("echo 3 e> a.txt e> a.txt");
+        assert!(
+            !dirs.test().join("a.txt").exists(),
+            "No file should be created on error"
+        );
+        let actual = nu!(
+            cwd: dirs.test(),
+            "echo 3 e> a.txt e> a.txt"
+        );
         assert!(actual.err.contains("Redirection can be set only once"));
+        assert!(
+            !dirs.test().join("a.txt").exists(),
+            "No file should be created on error"
+        );
+    });
 }