code: def test_julian_day():
      # Using Vallado 2007 "Fundamentals of Astrodynamics and Applications"
      # Example 3.4
      dt = datetime(1996, 10, 26, 14, 20)
      jd = _julian_day(dt)
      assert pytest.approx(jd) == 2450383.09722222
  
imports: from datetime import datetime
  import pytest
  from cartopy.feature.nightshade import Nightshade, _julian_day, _solar_position
label_desc: Use image node_id 1 for calling a global function with example usage: test_julian_day() without return types