### Question:
Line { public void set(double x1, double y1, double x2, double y2) { this.x1 = x1; this.y1 = y1; this.x2 = x2; this.y2 = y2; } Line();  Line(double x1, double y1, double x2, double y2); void set(double x1, double y1, double x2, double y2); double getX1(); double getX2(); double getY1(); double getY2(); @Override int hashCode(); @Override boolean equals(Object object); @Override String toString();  }### Answer:
@Test void testSet() { final Line line = new Line(); line.set(1.5, 2.5, 3.5, 4.5); assertEquals(1.5, line.getX1()); assertEquals(2.5, line.getY1()); assertEquals(3.5, line.getX2()); assertEquals(4.5, line.getY2()); }