code: def test_terms():
      t = terms("a")
      assert isinstance(t, Term)
      a, b, c = Term("a"), Term("b"), Term("c")
      assert t == a
      ts = terms(("a", "b", "c"))
      assert ts == (a, b, c)
      # a string without separator chars returns one symbol.  This is the
      # sympy 0.7 behavior
      assert terms("abc") == Term("abc")
      # separators return multiple symbols
      assert terms("a b c") == (a, b, c)
      assert terms("a, b, c") == (a, b, c)
      # no arg is an error
      pytest.raises(TypeError, terms)
      # but empty arg returns empty tuple
      assert terms(()) == ()
      # Test behavior of deprecated each_char kwarg
      pytest.raises(TypeError, terms, "abc", each_char=True)
  
imports: from warnings import catch_warnings, simplefilter
  import numpy
  import pytest
  import sympy
  from numpy.core.records import fromrecords
  from numpy.testing import assert_almost_equal, assert_array_equal
  from sympy.utilities.lambdify import implemented_function
  from nipy.utils import VisibleDeprecationWarning
  from ..None import formulae
  from ..formulae import Term, terms
label_desc: Use image node_id 1 for calling a global function with example usage: test_terms() without return types