diff --git a/src/ssort/_parsing.py b/src/ssort/_parsing.py
index 24d3e5f..969d81f 100644
--- a/src/ssort/_parsing.py
+++ b/src/ssort/_parsing.py
@@ -8,6 +8,19 @@
 from ssort._statements import Statement
 
 
+def _build_row_lengths_offsets(text):
+    # Build an index of row lengths and start offsets to enable fast string
+    # indexing using ast row/column coordinates.
+    row_lengths = []
+    row_offsets = [0]
+    for offset, char in enumerate(text):
+        if char == "\n":
+            row_lengths.append(offset - row_offsets[-1])
+            row_offsets.append(offset + 1)
+    row_lengths.append(len(text) - row_offsets[-1])
+    return row_lengths, row_offsets
+
+
 def _find_start(node):
     if (
         isinstance(node, (ast.FunctionDef, ast.AsyncFunctionDef, ast.ClassDef))
@@ -29,17 +42,8 @@ def split(
     nodes,
     next_row=0,
     next_col=0,
-    indent=0,
 ):
-    # Build an index of row lengths and start offsets to enable fast string
-    # indexing using ast row/column coordinates.
-    row_lengths = []
-    row_offsets = [0]
-    for offset, char in enumerate(root_text):
-        if char == "\n":
-            row_lengths.append(offset - row_offsets[-1])
-            row_offsets.append(offset + 1)
-    row_lengths.append(len(root_text) - row_offsets[-1])
+    row_lengths, row_offsets = _build_row_lengths_offsets(root_text)
 
     nodes = iter(nodes)
 
@@ -106,15 +110,7 @@ def split_class(statement):
     text = statement.text
     text_padded = statement.text_padded()
 
-    # Build an index of row lengths and start offsets to enable fast string
-    # indexing using ast row/column coordinates.
-    row_lengths = []
-    row_offsets = [0]
-    for offset, char in enumerate(text_padded):
-        if char == "\n":
-            row_lengths.append(offset - row_offsets[-1])
-            row_offsets.append(offset + 1)
-    row_lengths.append(len(text_padded) - row_offsets[-1])
+    _, row_offsets = _build_row_lengths_offsets(text_padded)
 
     tokens = iter(generate_tokens(StringIO(text_padded).readline))
 
diff --git a/tests/test_ast.py b/tests/test_ast.py
index 77c445f..5f400c0 100644
--- a/tests/test_ast.py
+++ b/tests/test_ast.py
@@ -30,6 +30,10 @@
 def _nodes_types(
     node_type: type[ast.AST] = ast.AST,
 ) -> Iterable[type[ast.AST]]:
+    # coverage package adds a coverage.parser.NodeList subclass
+    if node_type.__module__ != "ast":
+        return
+
     # Skip deprecated AST nodes.
     if issubclass(node_type, _deprecated_node_types):
         return
diff --git a/tests/test_split.py b/tests/test_split.py
index 754c99c..8a81773 100644
--- a/tests/test_split.py
+++ b/tests/test_split.py
@@ -1,5 +1,14 @@
+import sys
+
+import pytest
+
 from ssort._parsing import parse, split_class
 
+type_parameter_syntax = pytest.mark.skipif(
+    sys.version_info < (3, 12),
+    reason="type parameter syntax was introduced in python 3.12",
+)
+
 
 def _split_text(source):
     return [
@@ -117,13 +126,38 @@ def test_split_class_decorators():
     assert actual == expected
 
 
+def test_split_class_decorator_single_line():
+    actual = _split_class("@decorator()\nclass A: key: int")
+    expected = "@decorator()\nclass A:", ["    key: int"]
+    assert actual == expected
+
+
 def test_split_class_leading_comment():
     actual = _split_class("# Comment.\nclass A:\n    pass")
     expected = "# Comment.\nclass A:", ["    pass"]
     assert actual == expected
 
 
+def test_split_class_leading_comment_single_line():
+    actual = _split_class("# Comment.\nclass A: pass")
+    expected = "# Comment.\nclass A:", ["    pass"]
+    assert actual == expected
+
+
 def test_split_class_multiple():
     actual = _split_class("def a():\n    pass\n\nclass A:\n    pass")
     expected = "\nclass A:", ["    pass"]
     assert actual == expected
+
+
+def test_split_class_with_bases():
+    actual = _split_class("class A(\n    B,\n): pass")
+    expected = "class A(\n    B,\n):", ["    pass"]
+    assert actual == expected
+
+
+@type_parameter_syntax
+def test_split_class_with_type_params():
+    actual = _split_class("class A[\n    B,\n]: pass")
+    expected = "class A[\n    B,\n]:", ["    pass"]
+    assert actual == expected