Improve test coverage.
diff --git a/org.jacoco.report.test/src/org/jacoco/report/internal/html/table/SortIndexTest.java b/org.jacoco.report.test/src/org/jacoco/report/internal/html/table/SortIndexTest.java
index 0164377..1712b33 100644
--- a/org.jacoco.report.test/src/org/jacoco/report/internal/html/table/SortIndexTest.java
+++ b/org.jacoco.report.test/src/org/jacoco/report/internal/html/table/SortIndexTest.java
@@ -58,6 +58,14 @@
 	}
 
 	@Test
+	public void testIncreaseBuffer() {
+		index.init(createList(15));
+		final List<Integer> list = createList(20);
+		index.init(list);
+		assertSequence(list);
+	}
+
+	@Test
 	public void testReverse() {
 		final List<Integer> list = createList(57);
 		Collections.reverse(list);