refactor: remove code smell java:S5786 (#2159)

https://sonarcloud.io/organizations/iluwatar/rules?open=java%3AS5786&rule_key=java%3AS5786

mediator/src/test/java/com/iluwatar/mediator/PartyImplTest.java

@@ -36,7 +36,7 @@ import org.junit.jupiter.api.Test;
  *
  * @author Jeroen Meulemeester
  */
-public class PartyImplTest {
+class PartyImplTest {
 
   /**
    * Verify if a member is notified when it's joining a party. Generate an action and see if the

mediator/src/test/java/com/iluwatar/mediator/PartyMemberTest.java

@@ -47,7 +47,7 @@ import org.slf4j.LoggerFactory;
  *
  * @author Jeroen Meulemeester
  */
-public class PartyMemberTest {
+class PartyMemberTest {
 
   static Stream<Arguments> dataProvider() {
     return Stream.of(
@@ -61,12 +61,12 @@ public class PartyMemberTest {
   private InMemoryAppender appender;
 
   @BeforeEach
-  public void setUp() {
+  void setUp() {
     appender = new InMemoryAppender(PartyMemberBase.class);
   }
 
   @AfterEach
-  public void tearDown() {
+  void tearDown() {
     appender.stop();
   }
 
@@ -75,7 +75,7 @@ public class PartyMemberTest {
    */
   @ParameterizedTest
   @MethodSource("dataProvider")
-  public void testPartyAction(Supplier<PartyMember> memberSupplier) {
+  void testPartyAction(Supplier<PartyMember> memberSupplier) {
     final var member = memberSupplier.get();
 
     for (final var action : Action.values()) {
@@ -91,7 +91,7 @@ public class PartyMemberTest {
    */
   @ParameterizedTest
   @MethodSource("dataProvider")
-  public void testAct(Supplier<PartyMember> memberSupplier) {
+  void testAct(Supplier<PartyMember> memberSupplier) {
     final var member = memberSupplier.get();
 
     member.act(Action.GOLD);
@@ -115,7 +115,7 @@ public class PartyMemberTest {
    */
   @ParameterizedTest
   @MethodSource("dataProvider")
-  public void testToString(Supplier<PartyMember> memberSupplier) {
+  void testToString(Supplier<PartyMember> memberSupplier) {
     final var member = memberSupplier.get();
     final var memberClass = member.getClass();
     assertEquals(memberClass.getSimpleName(), member.toString());