Modified to extent ContinuousDistributionAbstractTest.

git-svn-id: https://svn.apache.org/repos/asf/jakarta/commons/proper/math/trunk@141253 13f79535-47bb-0310-9956-ffa450edef68

src/test/org/apache/commons/math/distribution/GammaDistributionTest.java

@@ -16,12 +16,73 @@
 
 package org.apache.commons.math.distribution;
 
-import junit.framework.TestCase;
-
 /**
- * @version $Revision: 1.16 $ $Date: 2004/05/23 21:34:19 $
+ * Test cases for GammaDistribution.
+ * Extends ContinuousDistributionAbstractTest.  See class javadoc for
+ * ContinuousDistributionAbstractTest for details.
+ * 
+ * @version $Revision: 1.17 $ $Date: 2004/05/31 00:55:22 $
  */
-public class GammaDistributionTest extends TestCase {
+public class GammaDistributionTest extends ContinuousDistributionAbstractTest {
+    
+    /**
+     * Constructor for GammaDistributionTest.
+     * @param name
+     */
+    public GammaDistributionTest(String name) {
+        super(name);
+    }
+    
+    //-------------- Implementations for abstract methods -----------------------
+    
+    /** Creates the default continuous distribution instance to use in tests. */
+    public ContinuousDistribution makeDistribution() {
+        return DistributionFactory.newInstance().createGammaDistribution(4d, 2d);
+    }   
+    
+    /** Creates the default cumulative probability distribution test input values */
+    public double[] makeCumulativeTestPoints() {
+        // quantiles computed using R version 1.8.1 (linux version)
+        return new double[] {0.8571048, 1.646497, 2.179731, 2.732637,
+            3.489539, 26.12448, 20.09024, 17.53455,
+            15.50731, 13.36157};
+    }
+    
+    /** Creates the default cumulative probability density test expected values */
+    public double[] makeCumulativeTestValues() {
+        return new double[] {0.001d, 0.01d, 0.025d, 0.05d, 0.1d, 0.999d,
+                0.990d, 0.975d, 0.950d, 0.900d}; 
+    }
+    
+    // --------------------- Override tolerance  --------------
+    protected void setup() throws Exception {
+        super.setUp();
+        setTolerance(1E-6);
+    }
+
+    //---------------------------- Additional test cases -------------------------
+    public void testParameterAccessors() {
+        GammaDistribution distribution = (GammaDistribution) getDistribution();
+        assertEquals(4d, distribution.getAlpha(), 0);
+        distribution.setAlpha(3d);
+        assertEquals(3d, distribution.getAlpha(), 0);
+        assertEquals(2d, distribution.getBeta(), 0);
+        distribution.setBeta(4d);
+        assertEquals(4d, distribution.getBeta(), 0);
+        try {
+            distribution.setAlpha(0d);
+            fail("Expecting IllegalArgumentException for alpha = 0");
+        } catch (IllegalArgumentException ex) {
+            // expected
+        }
+        try {
+            distribution.setBeta(0d);
+            fail("Expecting IllegalArgumentException for beta = 0");
+        } catch (IllegalArgumentException ex) {
+            // expected
+        }
+    } 
+    
     public void testProbabilities() throws Exception {
         testProbability(-1.000, 4.0, 2.0, .0000);
         testProbability(15.501, 4.0, 2.0, .9499);