Bugfix: python add blank lines (#1944)

* Don't add newlines when not a control statement for Python
* Add test for accidental newline fix
* Add docstring detection to avoid adding unnecessarily newlines
* Add tests for docstring detection

test/fixers/test_python_add_blank_lines_fixer.vader

@@ -6,15 +6,22 @@ After:
 
 Given python(Some Python without blank lines):
   def foo():
+      """ This is a simple test docstring """
       return 1
 
 
   def bar():
+      '''This is another simple test docstring'''
       return 1
       return 4
 
 
   def bar():
+      """
+      This is a multi-line
+      docstring
+      """
+
       if x:
           pass
           for l in x:
@@ -44,16 +51,25 @@ Execute(Blank lines should be added appropriately):
 
 Expect python(Newlines should be added):
   def foo():
+      """ This is a simple test docstring """
+
       return 1
 
 
   def bar():
+      '''This is another simple test docstring'''
+
       return 1
 
       return 4
 
 
   def bar():
+      """
+      This is a multi-line
+      docstring
+      """
+
       if x:
           pass
 
@@ -109,3 +125,43 @@ Expect python(extra newlines shouldn't be added to the main block):
 
   if __name__ == '__main__':
       main()
+
+
+Given python(A file with variables/docstring that start with a control statement):
+  def some():
+      """
+      This is a docstring that contains an
+      break control statement and also contains a
+      return something funny.
+      """
+
+      continue_some_var = True
+      forward_something = False
+
+      if (
+          continue_some_var and
+          forwarded_something
+      ):
+          return True
+
+
+Execute(Fix the file):
+  let g:ale_fixers = {'python': ['add_blank_lines_for_python_control_statements']}
+  ALEFix
+
+Expect python(Extra new lines are not added to the file):
+  def some():
+      """
+      This is a docstring that contains an
+      break control statement and also contains a
+      return something funny.
+      """
+
+      continue_some_var = True
+      forward_something = False
+
+      if (
+          continue_some_var and
+          forwarded_something
+      ):
+          return True