style: include UTAO_JUNIT_ASSERTION_ODDITIES_IMPOSSIBLE_NULL

Author: vil02

spotbugs-exclude.xml

@@ -216,9 +216,6 @@
     <Match>
         <Bug pattern="UTAO_JUNIT_ASSERTION_ODDITIES_INEXACT_DOUBLE" />
     </Match>
-    <Match>
-        <Bug pattern="UTAO_JUNIT_ASSERTION_ODDITIES_IMPOSSIBLE_NULL" />
-    </Match>
     <!-- find-sec-bugs -->
     <Match>
         <Bug pattern="PREDICTABLE_RANDOM" />

src/test/java/com/thealgorithms/compression/LZ78Test.java

@@ -1,7 +1,6 @@
 package com.thealgorithms.compression;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
-import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.util.List;
@@ -286,7 +285,6 @@ void testTokenStructure() {
         // All tokens should have valid indices (>= 0)
         for (LZ78.Token token : compressed) {
             assertTrue(token.index() >= 0);
-            assertNotNull(token.nextChar());
         }
 
         String decompressed = LZ78.decompress(compressed);