### Question:
Vector2f extends AVector2 { public static Vector2f copy(final IVector2 xy) { return new Vector2f(xy.x(), xy.y()); } private  Vector2f(); private  Vector2f(final double x, final double y); static Vector2f fromX(final double x); static Vector2f fromY(final double y); static Vector2f fromXY(final double x, final double y); static Vector2f fromAngle(final double angle); static Vector2f fromAngleLength(final double angle, final double length); static Vector2f copy(final IVector2 xy); static Vector2f zero(); @Override IVector2 copy(); @Override Vector2 getXYVector(); @Override double x(); @Override double y(); static final Vector2f X_AXIS; static final Vector2f Y_AXIS; static final Vector2f ZERO_VECTOR; }### Answer:
@Test public void testCopy() { assertThat(Vector2f.copy(Vector2.fromXY(42, 1337))).isEqualTo(Vector2.fromXY(42, 1337)); assertThat(Vector2f.copy(Vector2.fromXY(42, 42))).isNotEqualTo(Vector2.fromXY(42, 1337)); }