### Question:
Vertex { public final int orientation(Vertex a, Vertex b, Vertex c) { double result = Geometry.leftOfPlane(a.x, a.y, a.z, b.x, b.y, b.z, c.x, c.y, c.z, x, y, z); if (result > 0.0) { return 1; } else if (result < 0.0) { return -1; } return 0; } Vertex(double i, double j, double k);  Vertex(double i, double j, double k, double scale); static Vertex[] getRandomPoints(Random random, int numberOfPoints,
                                           double radius, boolean inSphere); static double random(Random random, double min, double max); static Vertex randomPoint(Random random, double min, double max); Point3f asPoint3f(); final void deleteAdjacent(); final double distanceSquared(Vertex p1); final Tetrahedron getAdjacent(); final int getOrder(); final int inSphere(Vertex a, Vertex b, Vertex c, Vertex d); final int orientation(Vertex a, Vertex b, Vertex c); final void reset(); final void setAdjacent(Tetrahedron tetrahedron); @Override String toString(); final double x; final double y; final double z; }### Answer:
@Test public void testOrientation() { Vertex[] fourCorners = Tetrahedralization.getFourCorners(); assertEquals(1, fourCorners[3].orientation(fourCorners[0], fourCorners[1], fourCorners[2])); assertEquals(-1, fourCorners[3].orientation(fourCorners[1], fourCorners[0], fourCorners[2])); assertEquals(0, new Vertex(100, 100, 0).orientation(new Vertex(1000, 100000, 0), new Vertex(0, -1456, 0), new Vertex(-2567, 0, 0))); assertEquals(1, fourCorners[0].orientation(fourCorners[2], fourCorners[1], fourCorners[3])); assertEquals(1, fourCorners[1].orientation(fourCorners[3], fourCorners[0], fourCorners[2])); assertEquals(1, fourCorners[2].orientation(fourCorners[0], fourCorners[3], fourCorners[1])); assertEquals(1, fourCorners[3].orientation(fourCorners[1], fourCorners[2], fourCorners[0])); }