Extend isPunctuation unit test

Change-Id: I670a7679e774e23aa914230bf2b72df2a3bd839e
diff --git a/src/test/java/org/ids_mannheim/UtilsTest.java b/src/test/java/org/ids_mannheim/UtilsTest.java
index 3d19ef9..40433d0 100644
--- a/src/test/java/org/ids_mannheim/UtilsTest.java
+++ b/src/test/java/org/ids_mannheim/UtilsTest.java
@@ -38,6 +38,8 @@
     @Test
     void isPunctuation() {
         assert(Utils.isPunctuation(",", ",", "$,"));
-        assert(Utils.isPunctuation(",", ",", "$,"));
+        assert(Utils.isPunctuation(".", ".", "$."));
+        assert(Utils.isPunctuation("'", "\"", "$("));
+        assert(! Utils.isPunctuation("in'", "in", "APPR"));
     }
 }
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