### Question:
CollisionFunctionLinear implements CollisionFunction { @Override public String toString() { return new StringBuilder().append(getClass().getSimpleName()) .append(" (a=") .append(a) .append(", b=") .append(b) .append(")") .toString(); } CollisionFunctionLinear(double a, double b); double getA(); double getB(); @Override double compute(double input); @Override int getRenderX(double input); @Override int getRenderY(double input); @Override CollisionFunctionType getType(); @Override int hashCode(); @Override boolean equals(Object object); @Override String toString();  }### Answer:
@Test void testToString() { assertEquals("CollisionFunctionLinear (a=2.0, b=3.0)", function.toString()); }