def test_center():
"""Test getting and setting the center."""
circle = Circle(1)
assert all(circle.center == (0, 0, 0))
center = (1, 1, 1)
circle.center = center
assert all(circle.center == center)
def test_moment_inertia(r, center):
circle = Circle(r)
assert np.all(np.asarray(circle.planar_moments_inertia) >= 0)
circle.center = center
area = np.pi * r**2
expected = [np.pi / 4 * r**4] * 3
expected[0] += area * center[0]**2
expected[1] += area * center[1]**2
expected[2] = area * center[0] * center[1]
np.testing.assert_allclose(circle.planar_moments_inertia[:2], expected[:2])
np.testing.assert_allclose(circle.planar_moments_inertia[2], expected[2])
assert circle.polar_moment_inertia == pytest.approx(sum(expected[:2]))
def test_eccentricity(r):
circle = Circle(r)
assert circle.eccentricity == 0
def test_iq(r):
circle = Circle(r)
assert circle.iq == 1
def test_set_area(area):
"""Test setting the area."""
circle = Circle(1)
circle.area = area
assert circle.area == approx(area)
assert circle.radius == approx((area / np.pi)**0.5)
def test_area(r):
circle = Circle(1)
circle.radius = r
assert circle.area == np.pi * r**2
def test_perimeter(r):
circle = Circle(1)
circle.radius = r
assert circle.perimeter == 2 * np.pi * r
assert circle.circumference == 2 * np.pi * r