Use central snapshot folder for each package

.fdignore

@@ -0,0 +1,2 @@
+*.snap
+*.snap.new

discourse-ui/src/backend/test_backend.rs

@@ -186,7 +186,9 @@ impl TestBackend {
             ops::Bound::Unbounded => self.cells.len(),
         };
 
-        self.cells[start..end].fill_with(Cell::default);
+        self.cells[start..end]
+            .iter_mut()
+            .for_each(|c| *c = Cell::default());
     }
 
     fn put_char(&mut self, c: char) {

discourse-ui/src/lib.rs

@@ -78,13 +78,14 @@ macro_rules! assert_backend_snapshot {
         $crate::assert_backend_snapshot!(@__impl ::insta::assert_display_snapshot!($value))
     };
 
-    (@__impl $($tt:tt)*) => {
+    (@__impl $($tt:tt)*) => {{
         ::insta::with_settings!({
-            snapshot_path => $crate::features::SNAPSHOT_PATH
+            snapshot_path => ::std::path::Path::new(env!("CARGO_MANIFEST_DIR")).join($crate::features::SNAPSHOT_PATH)
         }, {
             $($tt)*
         })
     }
+    }
 }
 
 #[cfg(test)]