Allow parse-time evaluation of calls, pipelines and subexpressions (#9499)

Co-authored-by: Antoine Stevan <44101798+amtoine@users.noreply.github.com>

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

@@ -7,6 +7,7 @@ mod parse;
 mod split;
 mod type_;
 
+use nu_test_support::{nu, pipeline};
 use std::path::MAIN_SEPARATOR;
 
 /// Helper function that joins string literals with '/' or '\', based on host OS
@@ -32,3 +33,9 @@ fn joins_path_on_other_than_windows() {
 
     assert_eq!(&actual, "sausage/bacon/spam");
 }
+
+#[test]
+fn const_path_relative_to() {
+    let actual = nu!("'/home/viking' | path relative-to '/home'");
+    assert_eq!(actual.out, "viking");
+}