Fixed most reported issues by SonarCloud.

extension-objects/src/main/java/concreteextensions/Commander.java

@@ -45,4 +45,8 @@ public class Commander implements CommanderExtension {
   public void commanderReady() {
     LOGGER.info("[Commander] " + unit.getName() + " is ready!");
   }
+
+  public CommanderUnit getUnit() {
+    return unit;
+  }
 }

extension-objects/src/main/java/concreteextensions/Sergeant.java

@@ -43,6 +43,10 @@ public class Sergeant implements SergeantExtension {
 
   @Override
   public void sergeantReady() {
-    LOGGER.info("[Sergeant] " + unit.getName() + " is ready! ");
+    LOGGER.info("[Sergeant] " + unit.getName() + " is ready!");
+  }
+
+  public SergeantUnit getUnit() {
+    return unit;
   }
 }

extension-objects/src/main/java/concreteextensions/Soldier.java

@@ -44,4 +44,8 @@ public class Soldier implements SoldierExtension {
   public void soldierReady() {
     LOGGER.info("[Solider] " + unit.getName() + "  is ready!");
   }
+
+  public SoldierUnit getUnit() {
+    return unit;
+  }
 }

extension-objects/src/test/java/AppTest.java

@@ -23,13 +23,16 @@
 
 import org.junit.jupiter.api.Test;
 
+import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
+
 /**
  * Created by Srdjan on 03-May-17.
  */
-public class AppTest {
+class AppTest {
+
   @Test
-  public void main() {
-    App.main(new String[]{});
+  void shouldExecuteApplicationWithoutException() {
+    assertDoesNotThrow(() -> App.main(new String[]{}));
   }
 
 }

extension-objects/src/test/java/concreteextensions/CommanderTest.java

@@ -23,17 +23,43 @@
 
 package concreteextensions;
 
+import ch.qos.logback.classic.Level;
+import ch.qos.logback.classic.Logger;
+import ch.qos.logback.classic.spi.ILoggingEvent;
+import ch.qos.logback.core.read.ListAppender;
 import org.junit.jupiter.api.Test;
+import org.slf4j.LoggerFactory;
 import units.CommanderUnit;
 
+import java.util.List;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
 /**
  * Created by Srdjan on 03-May-17.
+ *
+ * Modified by ToxicDreamz on 15-Aug-20
  */
-public class CommanderTest {
+class CommanderTest {
+
   @Test
-  public void commanderReady() {
+  void shouldExecuteCommanderReady() {
+
+    Logger commanderLogger = (Logger) LoggerFactory.getLogger(Commander.class);
+
+    ListAppender<ILoggingEvent> listAppender = new ListAppender<>();
+    listAppender.start();
+
+    commanderLogger.addAppender(listAppender);
+
     final var commander = new Commander(new CommanderUnit("CommanderUnitTest"));
     commander.commanderReady();
+
+    List<ILoggingEvent> logsList = listAppender.list;
+    assertEquals("[Commander] " + commander.getUnit().getName() + " is ready!", logsList.get(0)
+            .getMessage());
+    assertEquals(Level.INFO, logsList.get(0)
+            .getLevel());
   }
 
 }

extension-objects/src/test/java/concreteextensions/SergeantTest.java

@@ -23,17 +23,41 @@
 
 package concreteextensions;
 
+import ch.qos.logback.classic.Level;
+import ch.qos.logback.classic.Logger;
+import ch.qos.logback.classic.spi.ILoggingEvent;
+import ch.qos.logback.core.read.ListAppender;
 import org.junit.jupiter.api.Test;
+import org.slf4j.LoggerFactory;
 import units.SergeantUnit;
 
+import java.util.List;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
 /**
  * Created by Srdjan on 03-May-17.
  */
-public class SergeantTest {
+class SergeantTest {
+
   @Test
-  public void sergeantReady() {
+  void sergeantReady() {
+
+    Logger sergeantLogger = (Logger) LoggerFactory.getLogger(Sergeant.class);
+
+    ListAppender<ILoggingEvent> listAppender = new ListAppender<>();
+    listAppender.start();
+
+    sergeantLogger.addAppender(listAppender);
+
     final var sergeant = new Sergeant(new SergeantUnit("SergeantUnitTest"));
     sergeant.sergeantReady();
+
+    List<ILoggingEvent> logsList = listAppender.list;
+    assertEquals("[Sergeant] " + sergeant.getUnit().getName() + " is ready!", logsList.get(0)
+            .getMessage());
+    assertEquals(Level.INFO, logsList.get(0)
+            .getLevel());
   }
 
 }

extension-objects/src/test/java/concreteextensions/SoldierTest.java

@@ -23,17 +23,41 @@
 
 package concreteextensions;
 
+import ch.qos.logback.classic.Level;
+import ch.qos.logback.classic.Logger;
+import ch.qos.logback.classic.spi.ILoggingEvent;
+import ch.qos.logback.core.read.ListAppender;
 import org.junit.jupiter.api.Test;
+import org.slf4j.LoggerFactory;
 import units.SoldierUnit;
 
+import java.util.List;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
 /**
  * Created by Srdjan on 03-May-17.
  */
-public class SoldierTest {
+class SoldierTest {
+
   @Test
-  public void soldierReady() {
+  void soldierReady() {
+
+    Logger soldierLogger = (Logger) LoggerFactory.getLogger(Soldier.class);
+
+    ListAppender<ILoggingEvent> listAppender = new ListAppender<>();
+    listAppender.start();
+
+    soldierLogger.addAppender(listAppender);
+
     final var soldier = new Soldier(new SoldierUnit("SoldierUnitTest"));
     soldier.soldierReady();
+
+    List<ILoggingEvent> logsList = listAppender.list;
+    assertEquals("[Soldier] " + soldier.getUnit().getName() + " is ready!", logsList.get(0)
+            .getMessage());
+    assertEquals(Level.INFO, logsList.get(0)
+            .getLevel());
   }
 
 }