Farm depth must use canonical path

Because on MacOS there's a symlink here

tests/helpers/mod.rs

@@ -82,16 +82,16 @@ impl LinkFarm {
     // return how many levels below root is the top of the link farm
     pub fn depth_below_root(&self) -> usize {
         use Component::*;
-        let depth = self
-            .tempdir
-            .path()
+        let canonical_path = self.tempdir.path().canonicalize().unwrap();
+        let depth = canonical_path
             .components()
             .filter(|c| matches!(c, Normal(_)))
             .count();
 
         println!(
-            "depth_below_root for {:?} is {}",
+            "depth_below_root for {:?} with canonical {:?} is {}",
             self.tempdir.path(),
+            canonical_path,
             depth
         );
         depth