1 files changed, 34 insertions, 0 deletions
diff --git a/creole/shared/diff_utils.py b/creole/shared/diff_utils.py
new file mode 100644
index 0000000..b6fa05d
--- /dev/null
+++ b/creole/shared/diff_utils.py
@@ -0,0 +1,34 @@
+"""
+    :copyleft: 2020 by python-creole team, see AUTHORS for more details.
+    :license: GNU GPL v3 or above, see LICENSE for more details.
+"""
+
+import difflib
+
+
+def unified_diff(old, new, filename=None):
+    """
+    Return text of unified diff between old and new.
+    """
+    if filename is None:
+        fromfile = 'old'
+        tofile = 'new'
+    else:
+        fromfile = f'old / {filename}'
+        tofile = f'new / {filename}'
+
+    if isinstance(old, str) and isinstance(new, str):
+        old = old.splitlines(keepends=True)
+        new = new.splitlines(keepends=True)
+
+    diff = difflib.unified_diff(old, new, fromfile=fromfile, tofile=tofile)
+
+    text = ''
+    for line in diff:
+        text += line
+
+        # Work around missing newline (http://bugs.python.org/issue2142).
+        if text and not line.endswith('\n'):
+            text += 'n\\ No newline at end of file\n'
+
+    return text