### Question:
Foo { public int foo( int n){ if (n > 0) { n--; } else { n++; } return n; }  int foo(  int n);  }### Answer:
@Test public void test01(){ assertEquals(9,new Foo().foo(10)); }
@Test public void test02(){ assertEquals(99,new Foo().foo(100)); }
@Test public void test03(){ assertEquals(0,new Foo().foo(0)); }
@Test public void test04(){ assertEquals(-9,new Foo().foo(-10)); }