Fix a bug in the python leading whitespace calculation.

Author: nedtwigg

python/selfie-lib/selfie_lib/EscapeLeadingWhitespace.py

@@ -33,7 +33,7 @@ def appropriate_for(cls, file_content: str) -> "EscapeLeadingWhitespace":
         common_whitespace = None
 
         for line in file_content.splitlines():
-            whitespace = "".join(c for c in line if c.isspace())
+            whitespace = line[0 : len(line) - len(line.lstrip())]
             if whitespace == "" or whitespace == " ":
                 continue
             elif all(c == " " for c in whitespace):

python/selfie-lib/tests/EscapeLeadingWhitespace_test.py

@@ -46,13 +46,14 @@ def test_detection():
     )
 
     # single spaces and tabs -> only tabs need escape
+    tab = "\t"
     test_string = f"""/*
  * Copyright
  */
 interface Foo [
-{'\t'} bar()
+{tab}bar()
 ]"""
     assert (
         EscapeLeadingWhitespace.appropriate_for(test_string)
-        == EscapeLeadingWhitespace.ALWAYS
+        == EscapeLeadingWhitespace.ONLY_ON_SPACE
     )