### Question:
VectorMath { static double getAngle(IVector2 vector) { return SumatraMath.atan2(vector.y(), vector.x()); } @SuppressWarnings("unused") private  VectorMath(); static double distancePP(final IVector2 a, final IVector2 b); static double distancePPSqr(final IVector2 a, final IVector2 b);  }### Answer:
@Test public void testGetAngle() { for (double angle = -2 * AngleMath.PI_TWO; angle < 2 * AngleMath.PI_TWO; angle += 0.1) { double normalizeAngle = AngleMath.normalizeAngle(angle); IVector2 vector = Vector2.fromAngle(angle); double resultAngle = VectorMath.getAngle(vector); assertThat(normalizeAngle).isCloseTo(resultAngle, within(1e-4)); assertThat(resultAngle).isBetween(-AngleMath.PI, AngleMath.PI); } }