Add test to demonstrate no extra line is prepended

1 files changed, 7 insertions, 0 deletions

diff --git a/test_isort.py b/test_isort.py
index 67eccc03..14cf5d7e 100644
--- a/test_isort.py
+++ b/test_isort.py
@@ -2132,3 +2132,10 @@ def test_future_below_encoding_issue_545():
                        '\n'
                        'print("hello")\n')
     assert SortImports(file_contents=test_input).output == expected_output
+
+
+def test_no_extra_lines_issue_557():
+    """Test to ensure no extra lines are prepended"""
+    test_input = 'import os\n'
+    assert SortImports(file_contents=test_input, force_alphabetical_sort=True,
+                       force_sort_within_sections=True).output == test_input