[commons-rng] 04/07: Add code coverage test for large FactorialLog cache size.

[aherbert]

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aherbert pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/commons-rng.git

commit c57635db14a2cd1931124c2de975486637e9d61c
Author: Alex Herbert <aherb...@apache.org>
AuthorDate: Wed Jul 31 23:22:15 2019 +0100

    Add code coverage test for large FactorialLog cache size.
---
 .../commons/rng/sampling/distribution/InternalUtilsTest.java  | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git 
a/commons-rng-sampling/src/test/java/org/apache/commons/rng/sampling/distribution/InternalUtilsTest.java
 
b/commons-rng-sampling/src/test/java/org/apache/commons/rng/sampling/distribution/InternalUtilsTest.java
index 86f41de..f91a7c4 100644
--- 
a/commons-rng-sampling/src/test/java/org/apache/commons/rng/sampling/distribution/InternalUtilsTest.java
+++ 
b/commons-rng-sampling/src/test/java/org/apache/commons/rng/sampling/distribution/InternalUtilsTest.java
@@ -62,6 +62,17 @@ public class InternalUtilsTest {
     }
 
     @Test
+    public void testFactorialLogCacheSizeAboveRepresentableFactorials() {
+        final int limit = MAX_REPRESENTABLE + 5;
+        FactorialLog factorialLog = FactorialLog.create().withCache(limit);
+        for (int n = MAX_REPRESENTABLE; n <= limit; n++) {
+            // Use Commons math to compute logGamma(1 + n);
+            double expected = Gamma.logGamma(1 + n);
+            Assert.assertEquals(expected, factorialLog.value(n), 1e-10);
+        }
+    }
+
+    @Test
     public void testFactorialLogCacheExpansion() {
         // There is no way to determine if the cache values were reused but 
this test
         // exercises the method to ensure it does not error.