GH-130 - Fall back to annotated class' name as system name.

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

@@ -22,7 +22,6 @@ import java.lang.annotation.RetentionPolicy;
 
 import org.junit.jupiter.api.Test;
 import org.springframework.modulith.Modulithic;
-import org.springframework.modulith.core.AnnotationModulithMetadata;
 
 /**
  * Unit tests for {@link AnnotationModulithMetadata}.
@@ -47,6 +46,14 @@ class AnnotationModulithMetadataUnitTest {
 		});
 	}
 
+	@Test // #130
+	void usesSimpleClassNameAsDefaultSystemName() {
+
+		assertThat(AnnotationModulithMetadata.of(Sample.class)).hasValueSatisfying(it -> {
+			assertThat(it.getSystemName()).hasValue(Sample.class.getSimpleName());
+		});
+	}
+
 	@Modulithic(useFullyQualifiedModuleNames = true)
 	static class Sample {}
 
@@ -55,6 +62,5 @@ class AnnotationModulithMetadataUnitTest {
 
 	@Retention(RetentionPolicy.RUNTIME)
 	@Modulithic(useFullyQualifiedModuleNames = true)
-	@interface Intermediate {
-	}
+	@interface Intermediate {}
 }

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

@@ -23,7 +23,6 @@ import org.junit.jupiter.api.Test;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
 import org.springframework.modulith.Modulith;
 import org.springframework.modulith.Modulithic;
-import org.springframework.modulith.core.ModulithMetadata;
 
 /**
  * Unit tests for {@link ModulithMetadata}.
@@ -53,7 +52,7 @@ class ModulithMetadataUnitTest {
 
 		assertThat(metadata.getAdditionalPackages()).isEmpty();
 		assertThat(metadata.getSharedModuleNames()).isEmpty();
-		assertThat(metadata.getSystemName()).isEmpty();
+		assertThat(metadata.getSystemName()).hasValue(SpringBootApplicationAnnotated.class.getSimpleName());
 		assertThat(metadata.useFullyQualifiedModuleNames()).isFalse();
 	}
 

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

@@ -0,0 +1,47 @@
+/*
+ * 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 org.springframework.modulith.core;
+
+import static org.assertj.core.api.Assertions.*;
+
+import org.junit.jupiter.api.Test;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+/**
+ * Unit tests for {@link SpringBootModulithMetadata}.
+ *
+ * @author Oliver Drotbohm
+ */
+class SpringBootModulithMetadataUnitTest {
+
+	@Test // #130
+	void usesClassNameAsSystemNameDefault() {
+
+		var metadata = SpringBootModulithMetadata.of(SpringBootApp.class);
+
+		assertThat(metadata).hasValueSatisfying(it -> {
+			assertThat(it.getSystemName()).hasValue(SpringBootApp.class.getSimpleName());
+		});
+	}
+
+	@Test // #130
+	void doesNotExposeASystemNameForPackageBasedMetadata() {
+		assertThat(SpringBootModulithMetadata.of("com.acme").getSystemName()).isEmpty();
+	}
+
+	@SpringBootApplication
+	private static class SpringBootApp {}
+}