Use variable separator when converting variable name from camelCase (#708)

Author: bhirsz

docs/releasenotes/unreleased/transformers.2.rst

@@ -0,0 +1,12 @@
+Use variable_separator when converting variable from camelCase in RenameVariables (#705)
+----------------------------------------------------------------------------------------
+
+Previously ``variable_separator`` configuration was not respected when converting variable names from camelCase to
+snake_case. In result variable names were converted with spaces as the separator::
+
+    # from
+    ${camelCase}
+    # to
+    ${camel case}
+
+Now the setting will be take into account.

robotidy/transformers/RenameVariables.py

@@ -99,7 +99,8 @@ def __init__(self):
         self._local = set()
         self._global = set()
 
-    def _get_var_name(self, variable: str) -> "str|None":
+    @staticmethod
+    def _get_var_name(variable: str) -> "str|None":
         if len(variable) > 1 and variable[0] in "$@&" and variable[1] != "{":
             variable = f"{variable[0]}{{{variable[1:]}}}"
         match = search_variable(variable, ignore_errors=True)
@@ -543,7 +544,8 @@ def rename(self, variable_value: str, case: VariableCase, strip_fn: str = "strip
         # split on variable attribute access like ${var['item']}, ${var.item}, ${var(method)}..
         variable_name, item_access = split_string_on_delimiter(variable_value)
         if self.convert_camel_case:
-            variable_name = self.CAMEL_CASE.sub(r" \1", variable_name)
+            var_sep = " " if self.variable_separator == VariableSeparator.SPACE else "_"
+            variable_name = self.CAMEL_CASE.sub(rf"{var_sep}\1", variable_name)
         if self.variable_separator != VariableSeparator.IGNORE:
             variable_name = variable_name.replace("_", " ")
             variable_name = self.MORE_THAN_2_SPACES.sub(" ", variable_name)

tests/atest/transformers/RenameVariables/expected/test_ignore_var_separator.robot

@@ -39,10 +39,10 @@ ${INLINE_EVAL}    ${{ eval }}
 ...    other ${VALUE}
 ...    ${{embedd_ ed}
 
-${CAMEL CASE NAME}    ${CAMEL CASE NAME}
-${CAMEL CASE NAME}    ${CAMEL CASE NAME}
-${CAMEL CASE NAME}    ${CAMEL CASE NAME}
-${CAMEL CASE NAME_WORD_CAMEL CASE}    ${CAMEL CASE NAME_WORD_CAMEL CASE}
+${CAMEL_CASE_NAME}    ${CAMEL_CASE_NAME}
+${CAMEL_CASE_NAME}    ${CAMEL_CASE_NAME}
+${CAMEL_CASE_NAME}    ${CAMEL_CASE_NAME}
+${CAMEL_CASE_NAME_WORD_CAMEL_CASE}    ${CAMEL_CASE_NAME_WORD_CAMEL_CASE}
 
 
 *** Test Cases ***
@@ -56,7 +56,7 @@ Assign
 
 Args
     Keyword    ${VARIABLE}
-    Keyword    ${V A _RI ABLES}
+    Keyword    ${V A _RI_ABLES}
     ...    value with ${_ VARIABLE _}
 
 For header