Use file_writer_config instead of config to get text_dir for Text() (#220)

* Use file_writer_config instead if config for Text()

Fixes a bug where a keyerror would be thrown when rendering a Text() mobject.

* Make testing_utils.py use file_writer_config.

Thank you @huguesdevimeux !

Co-authored-by: Aathish Sivasubrahmanian <aathishs@Aathishs-MacBook-Air.local>

Author: Aathish04

manim/mobject/svg/text_mobject.py

@@ -5,7 +5,7 @@
 import cairo
 
 from ...constants import *
-from ...config import config
+from ...config import config,file_writer_config
 from ...container.container import Container
 from ...logger import logger
 from ...mobject.geometry import Dot, Rectangle
@@ -96,7 +96,7 @@ def __init__(self, text, **config):
     def get_space_width(self):
         size = self.size * 10
 
-        dir_name = config['text_dir']
+        dir_name = file_writer_config['text_dir']
         file_name = os.path.join(dir_name, "space") + '.svg'
 
         surface = cairo.SVGSurface(file_name, 600, 400)
@@ -291,8 +291,7 @@ def text2svg(self):
         if self.font == '':
             if NOT_SETTING_FONT_MSG != '':
                 logger.warning(NOT_SETTING_FONT_MSG)
-
-        dir_name = config['text_dir']
+        dir_name = file_writer_config['text_dir']
         hash_name = self.text2hash()
         file_name = os.path.join(dir_name, hash_name)+'.svg'
         if os.path.exists(file_name):

tests/testing_utils.py

@@ -38,7 +38,7 @@ def __init__(self, scene_object, module_tested, caching_needed=False):
         self.path_tests_data = os.path.join('tests', 'tests_data', module_tested)
 
         if caching_needed:
-            config['text_dir'] = os.path.join(
+            file_writer_config['text_dir'] = os.path.join(
                 self.path_tests_medias_cache, scene_object.__name__, 'Text')
             file_writer_config['tex_dir'] = os.path.join(
                 self.path_tests_medias_cache, scene_object.__name__, 'Tex')