@Test
public void testInterpolant() {

  double tol = 1e-3;
  assertEquals(0, TransitioningCompositeClock.interpolate(0, 10, 0), tol);
  assertEquals(1, TransitioningCompositeClock.interpolate(1, 10, 0), tol);
  assertEquals(10, TransitioningCompositeClock.interpolate(0, 10, 1), tol);
  assertEquals(5, TransitioningCompositeClock.interpolate(0, 10, 0.5), tol);
  // Test derivatives
  double epsilon = 1e-4;
  double dydx0 = (TransitioningCompositeClock.interpolate(0, 1, epsilon)
      - TransitioningCompositeClock.interpolate(0, 1, 0)) / epsilon;
  assertEquals(0.0, dydx0, tol);
  double dydx1 = (TransitioningCompositeClock.interpolate(0, 1, 1)
      - TransitioningCompositeClock.interpolate(0, 1, 1 - epsilon)) / epsilon;
  assertEquals(0.0, dydx1, tol);
}