### Question:
IrmGPCM2 extends AbstractItemResponseModel { public double[] getThresholdParameters(){ return threshold; } IrmGPCM2(double discrimination, double difficulty, double[] threshold, double D); double probability(double theta, double[] iparam, int category, double D); double probability(double theta, int category); double cumulativeProbability(double theta, int category); double derivTheta(double theta); double expectedValue(double theta); double[] nonZeroPrior(double[] param); void setDiscriminationPrior(ItemParamPrior discriminationPrior); void setDifficultyPrior(ItemParamPrior difficultyPrior); void setGuessingPrior(ItemParamPrior guessingPrior); void setSlippingPrior(ItemParamPrior slippingPrior); void setStepPriorAt(ItemParamPrior prior, int index); double[] gradient(double theta, double[] iparam, int k, double D); double[] gradient(double theta, int k); double addPriorsToLogLikelihood(double ll, double[] iparam); double[] addPriorsToLogLikelihoodGradient(double[] loglikegrad, double[] iparam); double itemInformationAt(double theta); void incrementMeanSigma(Mean mean, StandardDeviation sd); void incrementMeanMean(Mean meanDiscrimination, Mean meanDifficulty); void scale(double intercept, double slope); int getNumberOfParameters(); int getNumberOfEstimatedParameters(); double getScalingConstant(); double tStarProbability(double theta, int category, double intercept, double slope); double tStarExpectedValue(double theta, double intercept, double slope); double tSharpProbability(double theta, int category, double intercept, double slope); double tSharpExpectedValue(double theta, double intercept, double slope); String toString(); IrmType getType(); double[] getItemParameterArray(); void setStandardErrors(double[] x); double getDifficulty(); void setDifficulty(double difficulty); double getProposalDifficulty(); void setProposalDifficulty(double difficulty); double getDifficultyStdError(); void setDifficultyStdError(double stdError); double getDiscrimination(); void setDiscrimination(double discrimination); void setProposalDiscrimination(double discrimination); double getDiscriminationStdError(); void setDiscriminationStdError(double stdError); double getGuessing(); void setGuessing(double guessing); void setProposalGuessing(double guessing); double getGuessingStdError(); void setGuessingStdError(double stdError); void setSlipping(double slipping); void setProposalSlipping(double slipping); void setSlippingStdError(double slipping); double getSlipping(); double getSlippingStdError(); double[] getThresholdParameters(); void setThresholdParameters(double[] thresholds); void setProposalThresholds(double[] thresholds); double[] getThresholdStdError(); void setThresholdStdError(double[] stdError); double[] getStepParameters(); void setStepParameters(double[] step); void setProposalStepParameters(double[] step); double[] getStepStdError(); void setStepStdError(double[] stdError); double acceptAllProposalValues();  }### Answer:
@Test public void probstepTest(){ System.out.println("Step Test"); IrmGPCM2 irm = new IrmGPCM2(discrimination, difficulty, threshold, 1.7); double[] s = irm.getThresholdParameters(); for(int i=0;i<s.length;i++){ assertEquals("Step Test: " + (i+1), threshold[i], s[i], 1e-15); } }