GH-157 - Improve aggregate lookup.

We now directly collect all aggregate types instead of looking up entities first.

spring-modulith-core/src/test/java/com/acme/withatbean/SampleAggregate.java

@@ -0,0 +1,34 @@
+/*
+ * Copyright 2023 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.acme.withatbean;
+
+import org.jmolecules.ddd.types.AggregateRoot;
+import org.jmolecules.ddd.types.Identifier;
+
+import com.acme.withatbean.SampleAggregate.SampleIdentifier;
+
+/**
+ * @author Oliver Drotbohm
+ */
+public class SampleAggregate implements AggregateRoot<SampleAggregate, SampleIdentifier> {
+
+	@Override
+	public SampleIdentifier getId() {
+		return null;
+	}
+
+	record SampleIdentifier() implements Identifier {}
+}

spring-modulith-core/src/test/java/org/springframework/modulith/core/ModuleUnitTest.java

@@ -25,6 +25,7 @@ import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.TestInstance;
 import org.junit.jupiter.api.TestInstance.Lifecycle;
 
+import com.acme.withatbean.SampleAggregate;
 import com.acme.withatbean.TestEvents.JMoleculesAnnotated;
 import com.acme.withatbean.TestEvents.JMoleculesImplementing;
 import com.tngtech.archunit.core.domain.JavaClass;
@@ -74,4 +75,12 @@ class ModuleUnitTest {
 	void usesCapitalizedNameAsDisplayNameByDefault() {
 		assertThat(module.getDisplayName()).isEqualTo("Withatbean");
 	}
+
+	@Test // GH-157
+	void detectsAggregates() {
+
+		assertThat(module.getAggregateRoots())
+				.<Class<?>> extracting(JavaClass::reflect)
+				.containsExactly(SampleAggregate.class);
+	}
 }