Use copy of test topology properties (#84)

fluent-kafka-streams-tests/src/main/java/com/bakdata/fluent_kafka_streams_tests/TestTopology.java

@@ -1,7 +1,7 @@
 /*
  * MIT License
  *
- * Copyright (c) 2023 bakdata
+ * Copyright (c) 2024 bakdata
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
@@ -34,6 +34,7 @@
 import java.nio.file.Path;
 import java.util.Collection;
 import java.util.Comparator;
+import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Map;
 import java.util.NoSuchElementException;
@@ -151,10 +152,11 @@ public TestTopology(final Function<? super Properties, ? extends Topology> topol
      * APPLICATION_ID_CONFIG, BOOTSTRAP_SERVERS_CONFIG
      */
     public TestTopology(final Function<? super Properties, ? extends Topology> topologyFactory,
-            final Map<Object, Object> properties) {
+            final Map<?, ?> properties) {
         this(topologyFactory, schemaRegistryUrl -> {
-            properties.put(AbstractKafkaSchemaSerDeConfig.SCHEMA_REGISTRY_URL_CONFIG, schemaRegistryUrl);
-            return properties;
+            final Map<Object, Object> newProperties = new HashMap<>(properties);
+            newProperties.put(AbstractKafkaSchemaSerDeConfig.SCHEMA_REGISTRY_URL_CONFIG, schemaRegistryUrl);
+            return Map.copyOf(newProperties);
         });
     }
 
@@ -180,7 +182,7 @@ public TestTopology(final Supplier<? extends Topology> topologyFactory,
      * @param properties The properties of the Kafka Streams application under test. Required entries:
      * APPLICATION_ID_CONFIG, BOOTSTRAP_SERVERS_CONFIG
      */
-    public TestTopology(final Supplier<? extends Topology> topologyFactory, final Map<Object, Object> properties) {
+    public TestTopology(final Supplier<? extends Topology> topologyFactory, final Map<?, ?> properties) {
         this(props -> topologyFactory.get(), properties);
     }
 
@@ -206,7 +208,7 @@ public TestTopology(final Topology topology,
      * @param properties The properties of the Kafka Streams application under test. Required entries:
      * APPLICATION_ID_CONFIG, BOOTSTRAP_SERVERS_CONFIG
      */
-    public TestTopology(final Topology topology, final Map<Object, Object> properties) {
+    public TestTopology(final Topology topology, final Map<?, ?> properties) {
         this(props -> topology, properties);
     }
 

fluent-kafka-streams-tests/src/test/java/com/bakdata/fluent_kafka_streams_tests/TestTopologyTest.java

@@ -0,0 +1,45 @@
+/*
+ * MIT License
+ *
+ * Copyright (c) 2024 bakdata
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+package com.bakdata.fluent_kafka_streams_tests;
+
+import static org.assertj.core.api.Assertions.assertThatCode;
+
+import com.bakdata.fluent_kafka_streams_tests.test_applications.MirrorAvro;
+import com.bakdata.fluent_kafka_streams_tests.test_types.City;
+import com.bakdata.fluent_kafka_streams_tests.test_types.Person;
+import java.util.Map;
+import org.junit.jupiter.api.Test;
+
+
+class TestTopologyTest {
+
+    @Test
+    void shouldUseImmutableProperties() {
+        final TestTopology<Person, City> testTopology =
+                new TestTopology<>(MirrorAvro::getTopology, Map.copyOf(MirrorAvro.getKafkaProperties()));
+        assertThatCode(testTopology::start).doesNotThrowAnyException();
+        testTopology.stop();
+    }
+}