extract infer_line_separator method

2 files changed, 10 insertions, 6 deletions

diff --git a/isort/isort.py b/isort/isort.py
index 5635133b..2b5a4a13 100644
--- a/isort/isort.py
+++ b/isort/isort.py
@@ -111,12 +111,7 @@ class SortImports(object):
         if self.config['line_ending']:
             self.line_separator = self.config['line_ending']
         else:
-            if '\r\n' in file_contents:
-                self.line_separator = '\r\n'
-            elif '\r' in file_contents:
-                self.line_separator = '\r'
-            else:
-                self.line_separator = '\n'
+            self.line_separator = utils.infer_line_separator(file_contents)
 
         self.in_lines = file_contents.split(self.line_separator)
         self.original_length = len(self.in_lines)
diff --git a/isort/utils.py b/isort/utils.py
index 1f1b5143..0f6f57bf 100644
--- a/isort/utils.py
+++ b/isort/utils.py
@@ -52,3 +52,12 @@ def difference(a: Iterable[Any], b: Container[Any]) -> List[Any]:
         if item not in b:
             d.append(item)
     return d
+
+
+def infer_line_separator(file_contents: str) -> str:
+    if '\r\n' in file_contents:
+        return '\r\n'
+    elif '\r' in file_contents:
+        return '\r'
+    else:
+        return '\n'