### Question:
MyMath implements MathConstants { public static double computeAngle(final long pX1, final long pY1, final long pX2, final long pY2) { return Math.atan2(pY2 - pY1, pX2 - pX1); } private  MyMath(); static double gudermannInverse(final double aLatitude); static double gudermann(final double y); static int mod(int number, final int modulus); static long floorToLong(final double pValue); static int floorToInt(final double pValue); static int getNextSquareNumberAbove(final float factor); static double getAngleDifference(double pStart, double pEnd, final Boolean pClockwise); static double cleanPositiveAngle(double pAngle); static double computeAngle(final long pX1, final long pY1, final long pX2, final long pY2); static void computeCirclePoint(final long pCenterX, final long pCenterY, final double pRadius,
										  final double pAngle, final PointL pOutput);  }### Answer:
@Test public void testComputeAngle() { final double delta = 1E-10; final long value = 10; Assert.assertEquals(0, MyMath.computeAngle(0, 0, value, 0), delta); Assert.assertEquals(Math.PI, MyMath.computeAngle(0, 0, -value, 0), delta); Assert.assertEquals(-Math.PI / 2, MyMath.computeAngle(0, 0, 0, -value), delta); Assert.assertEquals(Math.PI / 2, MyMath.computeAngle(0, 0, 0, value), delta); Assert.assertEquals(-Math.PI / 4, MyMath.computeAngle(0, 0, value, -value), delta); Assert.assertEquals(Math.PI / 4, MyMath.computeAngle(0, 0, value, value), delta); Assert.assertEquals(-3 * Math.PI / 4, MyMath.computeAngle(0, 0, -value, -value), delta); Assert.assertEquals(3 * Math.PI / 4, MyMath.computeAngle(0, 0, -value, value), delta); }