fix camel_to_underscore

Author: youben11

pyls/_utils.py

@@ -202,4 +202,5 @@ def is_process_alive(pid):
 
 
 def camel_to_underscore(camelcase):
-    return re.sub('([A-Z]+)', r'_\1', camelcase).lower()
+    s1 = re.sub('([^_])([A-Z][a-z]+)', r'\1_\2', camelcase)
+    return re.sub('([a-z0-9])([A-Z])', r'\1_\2', s1).lower()

test/test_utils.py

@@ -93,3 +93,9 @@ def test_camel_to_underscore():
     assert _utils.camel_to_underscore('camelCase') == 'camel_case'
     assert _utils.camel_to_underscore('hangClosing') == 'hang_closing'
     assert _utils.camel_to_underscore('ignore') == 'ignore'
+    assert _utils.camel_to_underscore('CamelCase') == 'camel_case'
+    assert _utils.camel_to_underscore('SomeLongCamelCase') == 'some_long_camel_case'
+    assert _utils.camel_to_underscore('already_using_underscore') == 'already_using_underscore'
+    assert _utils.camel_to_underscore('Using_only_someUnderscore') == 'using_only_some_underscore'
+    assert _utils.camel_to_underscore('Using_Only_Some_underscore') == 'using_only_some_underscore'
+    assert _utils.camel_to_underscore('ALL_UPPER_CASE') == 'all_upper_case'