player_management: selectPlayer adds new players to player-list

src/main/java/de/tims/player_management/PlayerManager.java

@@ -27,7 +27,11 @@ public class PlayerManager {
 			}
 		}
 		
-		return new Player(playerName, 0);
+		Player newPlayer = new Player(playerName, 0);
+		
+		players.add(newPlayer);
+		
+		return newPlayer;
 	}
 
 	public void loadPlayers(String fileName) {

src/test/java/de/tims/player_management/PlayerManagerTest.java

@@ -5,9 +5,11 @@ import static org.assertj.core.api.Assertions.*;
 import java.io.File;
 import java.io.FileWriter;
 import java.io.IOException;
+import java.util.LinkedList;
 import java.util.List;
 import java.util.stream.Stream;
 
+import org.junit.jupiter.api.Test;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.Arguments;
 import org.junit.jupiter.params.provider.MethodSource;
@@ -25,11 +27,11 @@ class PlayerManagerTest {
 	}
 	
 	private static Stream<Arguments> testCasesForSelectPlayer() {
-		return Stream.of(Arguments.of("NoPlayersYetReturnNewPlayer", List.of(), 
+		return Stream.of(Arguments.of("NoPlayersYetReturnNewPlayer", new LinkedList<Player>(List.of()), 
 						"Tobias", new Player("Tobias", 0)),
-				Arguments.of("NoPlayerWithNameInListReturnNewPlayer", List.of(new Player("Steffen", 40), new Player("Lorenz", 60)),
+				Arguments.of("NoPlayerWithNameInListReturnNewPlayer", new LinkedList<Player>(List.of(new Player("Steffen", 40), new Player("Lorenz", 60))),
 						"Tobias", new Player("Tobias", 0)),
-				Arguments.of("PlayerWithNameInListReturnPlayerInList",  List.of(new Player("Steffen", 40), new Player("Tobias", 50)),
+				Arguments.of("PlayerWithNameInListReturnPlayerInList",  new LinkedList<Player>(List.of(new Player("Steffen", 40), new Player("Tobias", 50))),
 						"Tobias", new Player("Tobias", 50)));
 	}
 	
@@ -74,5 +76,35 @@ class PlayerManagerTest {
 				Arguments.of("WriteElementsOfListToFile", "src/test/java/resources/player_testdata2.csv", 
 						List.of(new Player("Tobias", 50), new Player("Steffen", 60))));
 	}
+	
+	@Test
+	void selectPlayerAddsNewPlayersToList() {
+		LinkedList<Player> players = new LinkedList<Player>();
+		players.add(new Player("Steffen", 40));
+		players.add(new Player("Max", 60));
+		
+		manager.setPlayers(players);
+		manager.selectPlayer("Tobias");
+		
+		List<Player> expectedResult = List.of(new Player("Steffen", 40), new Player("Max", 60), new Player("Tobias", 0));
+		List<Player> calculatedResult = manager.getPlayers();
+		
+		assertThat(calculatedResult).describedAs("SelectNewPlayerAddsNewPlayerToPlayersList").isEqualTo(expectedResult);
+	}
+	
+	@Test
+	void selectExistingPlayerDoesntChangeTheList() {
+		LinkedList<Player> players = new LinkedList<Player>();
+		players.add(new Player("Steffen", 40));
+		players.add(new Player("Max", 60));
+		
+		manager.setPlayers(players);
+		manager.selectPlayer("Max");
+		
+		List<Player> expectedResult = List.of(new Player("Steffen", 40), new Player("Max", 60));
+		List<Player> calculatedResult = manager.getPlayers();
+		
+		assertThat(calculatedResult).describedAs("SelectNewPlayerAddsNewPlayerToPlayersList").isEqualTo(expectedResult);
+	}
 
 }