Add edge case coverage for logProbability
diff --git a/commons-statistics-distribution/src/test/java/org/apache/commons/statistics/distribution/DiscreteDistributionAbstractTest.java b/commons-statistics-distribution/src/test/java/org/apache/commons/statistics/distribution/DiscreteDistributionAbstractTest.java
index 03273f9..fcc46b3 100644
--- a/commons-statistics-distribution/src/test/java/org/apache/commons/statistics/distribution/DiscreteDistributionAbstractTest.java
+++ b/commons-statistics-distribution/src/test/java/org/apache/commons/statistics/distribution/DiscreteDistributionAbstractTest.java
@@ -440,6 +440,12 @@
Assertions.assertEquals(1.0, distribution.cumulativeProbability(above));
Assertions.assertEquals(0.0, distribution.survivalProbability(above));
}
+
+ // Test the logProbability at the support bound. This hits edge case coverage for logProbability.
+ // It is assumed the log probability may support a value when the plain probability will be zero.
+ // So do not test Math.log(distribution.probability(x)) == distribution.logProbability(x)
+ Assertions.assertEquals(distribution.probability(lo), Math.exp(distribution.logProbability(lo)), getTolerance());
+ Assertions.assertEquals(distribution.probability(hi), Math.exp(distribution.logProbability(hi)), getTolerance());
}
@Test
