Sort relative imports by parent level descending (#856)

resources/test/fixtures/isort/order_relative_imports_by_level.py

@@ -0,0 +1,4 @@
+from .a import a
+from ..a import a
+from ..b import a
+from .b import a

src/isort/mod.rs

@@ -1,3 +1,4 @@
+use std::cmp::Reverse;
 use std::collections::{BTreeMap, BTreeSet};
 use std::path::PathBuf;
 
@@ -381,6 +382,7 @@ fn sort_imports(block: ImportBlock) -> OrderedImportBlock {
                 // Sort each `StmtKind::ImportFrom` by module key, breaking ties based on
                 // members.
                 (
+                    Reverse(import_from.level),
                     import_from
                         .module
                         .as_ref()
@@ -477,6 +479,7 @@ mod tests {
     #[test_case(Path::new("leading_prefix.py"))]
     #[test_case(Path::new("no_reorder_within_section.py"))]
     #[test_case(Path::new("order_by_type.py"))]
+    #[test_case(Path::new("order_relative_imports_by_level.py"))]
     #[test_case(Path::new("preserve_comment_order.py"))]
     #[test_case(Path::new("preserve_indentation.py"))]
     #[test_case(Path::new("reorder_within_section.py"))]

src/isort/snapshots/ruff__isort__tests__order_relative_imports_by_level.py.snap

@@ -0,0 +1,22 @@
+---
+source: src/isort/mod.rs
+expression: checks
+---
+- kind: UnsortedImports
+  location:
+    row: 1
+    column: 0
+  end_location:
+    row: 5
+    column: 0
+  fix:
+    patch:
+      content: "from ..a import a\nfrom ..b import a\nfrom .a import a\nfrom .b import a\n"
+      location:
+        row: 1
+        column: 0
+      end_location:
+        row: 5
+        column: 0
+    applied: false
+