docstr: Test that it can be called with no value.
docstr_tok: ["Test","that","it","can","be","called","with","no","value","."]
code: def test_just_label(self):
      """Test that it can be called with no value."""
      st.number_input("the label")
  
      c = self.get_delta_from_queue().new_element.number_input
      self.assertEqual(c.label, "the label")
      self.assertEqual(
          c.label_visibility.value,
          LabelVisibilityMessage.LabelVisibilityOptions.VISIBLE,
      )
      self.assertEqual(c.default, 0.0)
      self.assertEqual(c.HasField("default"), True)
      self.assertEqual(c.has_min, False)
      self.assertEqual(c.has_max, False)
      self.assertEqual(c.disabled, False)
      self.assertEqual(c.placeholder, "")
  
imports: from unittest.mock import MagicMock, patch
  import pytest
  from parameterized import parameterized
  import streamlit
  from streamlit.errors import StreamlitAPIException
  from streamlit.js_number import JSNumber
  from streamlit.proto.Alert_pb2 import Alert
  from streamlit.proto.LabelVisibilityMessage_pb2 import LabelVisibilityMessage
  from streamlit.proto.NumberInput_pb2 import NumberInput
  from streamlit.proto.WidgetStates_pb2 import WidgetState
  from streamlit.testing.v1.app_test import AppTest
  from tests.delta_generator_test_case import DeltaGeneratorTestCase
label_desc: Use image node_id 3 for calling the NumberInputTest obj's underlying member method code with example usage: obj.test_just_label() without return types