class_docstr: Test ability to marshall text_area protos.
class_docstr_tok: ["Test","ability","to","marshall","text_area","protos","."]
docstr: Test that it can be called with placeholder
docstr_tok: ["Test","that","it","can","be","called","with","placeholder"]
code: def test_placeholder(self):
      """Test that it can be called with placeholder"""
      st.text_area("the label", "", placeholder="testing")
  
      c = self.get_delta_from_queue().new_element.text_area
      self.assertEqual(c.label, "the label")
      self.assertEqual(c.default, "")
      self.assertEqual(c.placeholder, "testing")
  
imports: import re
  from unittest.mock import MagicMock, patch
  from parameterized import parameterized
  import streamlit
  from streamlit.errors import StreamlitAPIException
  from streamlit.proto.LabelVisibilityMessage_pb2 import LabelVisibilityMessage
  from streamlit.testing.v1.app_test import AppTest
  from tests.delta_generator_test_case import DeltaGeneratorTestCase
label_desc: Use image node_id 6 for calling the TextAreaTest obj's underlying member method code with example usage: obj.test_placeholder() without return types