code: def test_TextExpression():
      exp = TextExpression("foo bar")
      assert_equal("foo bar", exp.expression(None))
      assert_equal(None, exp.definition(None, ("120", "")))
      assert_raises(TypeError, TextExpression, 4)
  
file_path: vispy/vispy/visuals/shaders/tests/test_function.py
imports: from vispy.visuals.shaders import Function, MainFunction, Variable, Varying, FunctionChain, StatementList
  from vispy.visuals.shaders.expression import FunctionCall, TextExpression
  from vispy.testing import assert_in, assert_not_in, assert_is, run_tests_if_main, assert_raises, assert_equal
label_desc: Use image node_id 3 for calling a global function with example usage: test_TextExpression() without return types