Improved test coverage.

Author: maisonobe

hipparchus-core/src/test/java/org/hipparchus/random/GammaGeneratorTest.java

@@ -18,6 +18,8 @@
 
 import org.hipparchus.distribution.RealDistribution;
 import org.hipparchus.distribution.continuous.GammaDistribution;
+import org.hipparchus.exception.LocalizedCoreFormats;
+import org.hipparchus.exception.MathIllegalStateException;
 import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.Test;
 
@@ -83,4 +85,15 @@ public void testVariance()
         }
     }
 
+    @Test
+    public void testMaxRejection()
+    {
+        try {
+            new GammaGenerator(new RandomAdaptorTest.ConstantGenerator(1.23), 2.3, 4.5).nextVariate();
+            Assertions.fail("an exception should have been thrown");
+        } catch (MathIllegalStateException mise) {
+            Assertions.assertEquals(LocalizedCoreFormats.INTERNAL_ERROR, mise.getSpecifier());
+        }
+    }
+
 }