[py] Avoid AttributeError and add to WebElement finders

Author: cgoldberg

py/selenium/webdriver/remote/webdriver.py

@@ -918,7 +918,7 @@ def find_element(self, by=By.ID, value: Optional[str] = None) -> WebElement:
             The first matching `WebElement` found on the page.
         """
         if by == "class name":
-            if " " in value.strip():
+            if value and any(char.isspace() for char in value.strip()):
                 raise InvalidSelectorException("Compound class names are not allowed.")
 
         by, value = self.locator_converter.convert(by, value)
@@ -958,7 +958,7 @@ def find_elements(self, by=By.ID, value: Optional[str] = None) -> list[WebElemen
             list of `WebElements` matching locator strategy found on the page.
         """
         if by == "class name":
-            if " " in value.strip():
+            if value and any(char.isspace() for char in value.strip()):
                 raise InvalidSelectorException("Compound class names are not allowed.")
 
         by, value = self.locator_converter.convert(by, value)

py/selenium/webdriver/remote/webelement.py

@@ -25,7 +25,7 @@
 from hashlib import md5 as md5_hash
 from io import BytesIO
 
-from selenium.common.exceptions import JavascriptException, WebDriverException
+from selenium.common.exceptions import InvalidSelectorException, JavascriptException, WebDriverException
 from selenium.webdriver.common.by import By
 from selenium.webdriver.common.utils import keys_to_typing
 
@@ -598,7 +598,12 @@ def find_element(self, by=By.ID, value=None) -> WebElement:
         WebElement
             The first matching `WebElement` found on the page.
         """
+        if by == "class name":
+            if value and any(char.isspace() for char in value.strip()):
+                raise InvalidSelectorException("Compound class names are not allowed.")
+
         by, value = self._parent.locator_converter.convert(by, value)
+
         return self._execute(Command.FIND_CHILD_ELEMENT, {"using": by, "value": value})["value"]
 
     def find_elements(self, by=By.ID, value=None) -> list[WebElement]:
@@ -627,7 +632,12 @@ def find_elements(self, by=By.ID, value=None) -> list[WebElement]:
         List[WebElement]
             list of `WebElements` matching locator strategy found on the page.
         """
+        if by == "class name":
+            if value and any(char.isspace() for char in value.strip()):
+                raise InvalidSelectorException("Compound class names are not allowed.")
+
         by, value = self._parent.locator_converter.convert(by, value)
+
         return self._execute(Command.FIND_CHILD_ELEMENTS, {"using": by, "value": value})["value"]
 
     def __hash__(self) -> int: