Fix the test run.

pom.xml

@@ -15,6 +15,7 @@
 	<version>0.0.1-SNAPSHOT</version>
 
 	<properties>
+		<logback.version>1.2.10</logback.version>
 		<slf4j.version>1.7.35</slf4j.version>
 	</properties>
 
@@ -22,7 +23,7 @@
 		<dependency>
 			<groupId>ch.fritteli.labyrinth</groupId>
 			<artifactId>labyrinth-generator</artifactId>
-			<version>0.0.2-SNAPSHOT</version>
+			<version>0.0.2</version>
 		</dependency>
 		<dependency>
 			<groupId>io.vavr</groupId>
@@ -44,7 +45,7 @@
 		<dependency>
 			<groupId>ch.qos.logback</groupId>
 			<artifactId>logback-classic</artifactId>
-			<version>1.2.10</version>
+			<version>${logback.version}</version>
 		</dependency>
 		<dependency>
 			<groupId>org.junit.jupiter</groupId>

src/main/java/ch/fritteli/labyrinth/server/LabyrinthServer.java

@@ -27,7 +27,8 @@ import java.net.InetSocketAddress;
 import java.net.URISyntaxException;
 import java.nio.charset.StandardCharsets;
 import java.util.concurrent.ExecutorService;
-import java.util.concurrent.Executors;
+import java.util.concurrent.SynchronousQueue;
+import java.util.concurrent.ThreadPoolExecutor;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.function.Function;
@@ -37,7 +38,13 @@ public class LabyrinthServer {
     @NonNull
     private final HttpServer httpServer;
     @NonNull
-    private final ExecutorService executorService = Executors.newCachedThreadPool();
+    private final ExecutorService executorService = new ThreadPoolExecutor(
+            0,
+            1_000,
+            5,
+            TimeUnit.SECONDS,
+            new SynchronousQueue<>()
+    );
 
     public LabyrinthServer(@NonNull final ServerConfig config) throws IOException, URISyntaxException {
         this.httpServer = HttpServer.create(new InetSocketAddress(config.getAddress(), config.getPort()), 5);

src/test/java/ch/fritteli/labyrinth/server/ServerConfigTest.java

@@ -4,7 +4,6 @@ import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
 import java.net.UnknownHostException;
-import java.util.Properties;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertThrows;
@@ -12,7 +11,8 @@ import static org.junit.jupiter.api.Assertions.assertThrows;
 class ServerConfigTest {
     @BeforeEach
     void clearSysProperties() {
-        System.setProperties(new Properties());
+        System.clearProperty(ServerConfig.SYSPROP_HOST);
+        System.clearProperty(ServerConfig.SYSPROP_PORT);
     }
 
     @Test