code: def test_interval():
      assert (interval(1, 1) == interval(1, 1, is_valid=True)) == (
          True,
          True,
      )
      assert (interval(1, 1) == interval(1, 1, is_valid=False)) == (
          True,
          False,
      )
      assert (interval(1, 1) == interval(1, 1, is_valid=None)) == (
          True,
          None,
      )
      assert (interval(1, 1.5) == interval(1, 2)) == (None, True)
      assert (interval(0, 1) == interval(2, 3)) == (False, True)
      assert (interval(0, 1) == interval(1, 2)) == (None, True)
      assert (interval(1, 2) != interval(1, 2)) == (False, True)
      assert (interval(1, 3) != interval(2, 3)) == (None, True)
      assert (interval(1, 3) != interval(-5, -3)) == (True, True)
      assert (interval(1, 3, is_valid=False) != interval(-5, -3)) == (
          True,
          False,
      )
      assert (interval(1, 3, is_valid=None) != interval(-5, 3)) == (
          None,
          None,
      )
      assert (interval(4, 4) != 4) == (False, True)
      assert (interval(1, 1) == 1) == (True, True)
      assert (interval(1, 3, is_valid=False) == interval(1, 3)) == (
          True,
          False,
      )
      assert (interval(1, 3, is_valid=None) == interval(1, 3)) == (
          True,
          None,
      )
      inter = interval(-5, 5)
      assert (interval(inter) == interval(-5, 5)) == (True, True)
      assert inter.width == 10
      assert 0 in inter
      assert -5 in inter
      assert 5 in inter
      assert interval(0, 3) in inter
      assert interval(-6, 2) not in inter
      assert -5.05 not in inter
      assert 5.3 not in inter
      interb = interval(-float("inf"), float("inf"))
      assert 0 in inter
      assert inter in interb
      assert interval(0, float("inf")) in interb
      assert interval(-float("inf"), 5) in interb
      assert interval(-1e50, 1e50) in interb
      assert (-interval(-1, -2, is_valid=False) == interval(1, 2)) == (
          True,
          False,
      )
      raises(ValueError, lambda: interval(1, 2, 3))
  
file_path: sympy/sympy/plotting/intervalmath/tests/test_intervalmath.py
imports: from sympy.plotting.intervalmath import interval
  from sympy.testing.pytest import raises
label_desc: Use image node_id 1 for calling a global function with example usage: test_interval() without return types