### Question:
Quadrilateral extends AQuadrilateral { @Override public final boolean equals(final Object o) { if (this == o) return true; if (o == null || getClass() != o.getClass()) return false; final Quadrilateral that = (Quadrilateral) o; return new EqualsBuilder() .append(corners, that.corners) .isEquals(); } @SuppressWarnings("unused") private  Quadrilateral(); private  Quadrilateral(final List<IVector2> corners); static IQuadrilateral fromCorners(final IVector2 a, final IVector2 b, final IVector2 c, final IVector2 d); static IQuadrilateral fromCorners(final List<IVector2> points); @Override List<IVector2> getCorners(); @Override final boolean equals(final Object o); @Override final int hashCode(); @Override List<IVector2> lineIntersections(final ILine line);  }### Answer:
@Test public void testEquals() { EqualsVerifier.forClass(Quadrilateral.class) .verify(); }