### Question:
AddFixedCurve implements Curve, ImmutableBean, Serializable { @Override public double yValue(double x) { return fixedCurve.yValue(x) + spreadCurve.yValue(x); } private  AddFixedCurve(
      Curve fixedCurve,
      Curve spreadCurve); static AddFixedCurve of(Curve fixedCurve, Curve spreadCurve); @Override CurveMetadata getMetadata(); @Override AddFixedCurve withMetadata(CurveMetadata metadata); @Override int getParameterCount(); @Override double getParameter(int parameterIndex); @Override ParameterMetadata getParameterMetadata(int parameterIndex); @Override AddFixedCurve withParameter(int parameterIndex, double newValue); @Override AddFixedCurve withPerturbation(ParameterPerturbation perturbation); @Override double yValue(double x); @Override UnitParameterSensitivity yValueParameterSensitivity(double x); @Override double firstDerivative(double x); @Override ImmutableList<Curve> split(); @Override AddFixedCurve withUnderlyingCurve(int curveIndex, Curve curve); static AddFixedCurve.Meta meta(); @Override AddFixedCurve.Meta metaBean(); Curve getFixedCurve(); Curve getSpreadCurve(); @Override boolean equals(Object obj); @Override int hashCode(); @Override String toString();  }### Answer:
@Test public void yValue() { for (int i = 0; i < NB_X_SAMPLE; i++) { double yComputed = ADD_FIXED_CURVE.yValue(X_SAMPLE[i]); double yExpected = FIXED_CURVE.yValue(X_SAMPLE[i]) + SPREAD_CURVE.yValue(X_SAMPLE[i]); assertThat(yComputed).isCloseTo(yExpected, offset(TOLERANCE_Y)); } }