Fix GrpcClientRegistrationSpec#packageClasses

spring-grpc-core/src/main/java/org/springframework/grpc/client/GrpcClientFactory.java

@@ -325,11 +325,8 @@ public GrpcClientRegistrationSpec packages(String... packages) {
 
 		public GrpcClientRegistrationSpec packageClasses(Class<?>... packageClasses) {
 			String[] packages = new String[packageClasses.length];
-			for (Class<?> basePackageClass : packageClasses) {
-				for (int i = 0; i < packageClasses.length; i++) {
-					String basePackage = ClassUtils.getPackageName(basePackageClass);
-					packages[i] = basePackage;
-				}
+			for (int i = 0; i < packageClasses.length; i++) {
+				packages[i] = ClassUtils.getPackageName(packageClasses[i]);
 			}
 			return packages(packages);
 		}

spring-grpc-core/src/test/java/org/springframework/grpc/client/GrpcClientFactoryTests.java

@@ -21,6 +21,8 @@
 
 import java.util.function.Supplier;
 
+import org.assertj.core.api.InstanceOfAssertFactories;
+import org.junit.jupiter.api.Nested;
 import org.junit.jupiter.api.Test;
 import org.mockito.Mockito;
 
@@ -30,14 +32,17 @@
 import org.springframework.context.support.StaticApplicationContext;
 import org.springframework.grpc.client.GrpcClientFactory.GrpcClientRegistrationSpec;
 import org.springframework.grpc.client.GrpcClientFactoryTests.MyProto.MyStub;
+import org.springframework.grpc.client.bar.Bar;
+import org.springframework.grpc.client.foo.ExtraFoo;
+import org.springframework.grpc.client.foo.Foo;
 
 import io.grpc.CallOptions;
 import io.grpc.Channel;
 import io.grpc.ManagedChannel;
 import io.grpc.kotlin.AbstractCoroutineStub;
 import io.grpc.stub.AbstractStub;
 
-public class GrpcClientFactoryTests {
+class GrpcClientFactoryTests {
 
 	private GrpcChannelFactory channelFactory = Mockito.mock(GrpcChannelFactory.class);
 
@@ -114,6 +119,42 @@ void testCoroutineStubFactoryAfterDefault() {
 		assertThat(factory.getClient("local", MyStub.class, null)).isNotNull();
 	}
 
+	@Nested // GH-361
+	class GrpcClientRegistrationSpecPackageClassesShould {
+
+		private GrpcClientRegistrationSpec spec = GrpcClientRegistrationSpec.of("local");
+
+		@Test
+		void returnSinglePackageGivenSingleClass() {
+			assertThat(spec.packageClasses(Foo.class)).extracting(GrpcClientRegistrationSpec::packages)
+				.asInstanceOf(InstanceOfAssertFactories.array(String[].class))
+				.containsExactly("org.springframework.grpc.client.foo");
+		}
+
+		@Test
+		void returnSinglePackageGivenMultipleClassesInSamePackage() {
+			assertThat(spec.packageClasses(Foo.class, ExtraFoo.class)).extracting(GrpcClientRegistrationSpec::packages)
+				.asInstanceOf(InstanceOfAssertFactories.array(String[].class))
+				.containsExactly("org.springframework.grpc.client.foo");
+		}
+
+		@Test
+		void returnMultiPackagesGivenMultipleClassesInDifferentPackage() {
+			assertThat(spec.packageClasses(Foo.class, Bar.class)).extracting(GrpcClientRegistrationSpec::packages)
+				.asInstanceOf(InstanceOfAssertFactories.array(String[].class))
+				.containsExactly("org.springframework.grpc.client.foo", "org.springframework.grpc.client.bar");
+		}
+
+		@Test
+		void returnMultiPackagesGivenMultipleClassesInSameAndDifferentPackage() {
+			assertThat(spec.packageClasses(Foo.class, Bar.class, ExtraFoo.class))
+				.extracting(GrpcClientRegistrationSpec::packages)
+				.asInstanceOf(InstanceOfAssertFactories.array(String[].class))
+				.containsExactly("org.springframework.grpc.client.foo", "org.springframework.grpc.client.bar");
+		}
+
+	}
+
 	static class OtherStubFactory implements StubFactory<OtherStub> {
 
 		@Override

spring-grpc-core/src/test/java/org/springframework/grpc/client/bar/Bar.java

@@ -0,0 +1,26 @@
+/*
+ * Copyright 2026-present 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.grpc.client.bar;
+
+/**
+ * Simple test record used to help test {@code GrpcClientRegistrationSpec} in
+ * {@code GrpcClientFactoryTests}.
+ *
+ * @param msg some context that can be used to differentiate instances
+ */
+public record Bar(String msg) {
+}

spring-grpc-core/src/test/java/org/springframework/grpc/client/foo/ExtraFoo.java

@@ -0,0 +1,26 @@
+/*
+ * Copyright 2026-present 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.grpc.client.foo;
+
+/**
+ * Simple test record used to help test {@code GrpcClientRegistrationSpec} in
+ * {@code GrpcClientFactoryTests}.
+ *
+ * @param msg some context that can be used to differentiate instances
+ */
+public record ExtraFoo(String msg) {
+}

spring-grpc-core/src/test/java/org/springframework/grpc/client/foo/Foo.java

@@ -0,0 +1,26 @@
+/*
+ * Copyright 2026-present 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.grpc.client.foo;
+
+/**
+ * Simple test record used to help test {@code GrpcClientRegistrationSpec} in
+ * {@code GrpcClientFactoryTests}.
+ *
+ * @param msg some context that can be used to differentiate instances
+ */
+public record Foo(String msg) {
+}

src/checkstyle/checkstyle-suppressions.xml

@@ -8,7 +8,8 @@
 	<suppress files="Proto" checks=".*"/>
 	<suppress files=".*Tests" checks="HideUtilityClassConstructor" />
 	<suppress files=".*Tests" checks="RegexpSinglelineJava" id="toLowerCaseWithoutLocale"/>
-	<suppress files=".*Tests" checks="RegexpSinglelineJava" id="toUpperCaseWithoutLocale"/>
+	<suppress files="GrpcClientFactoryTests" checks="RegexpSinglelineJava" id="toUpperCaseWithoutLocale"/>
+	<suppress files="" checks="RedundantModifier" />
 	<suppress files="[\\/]spring-grpc-docs[\\/]" checks="JavadocPackage|JavadocType|JavadocVariable|SpringDeprecatedCheck" />
 	<suppress files="[\\/]spring-grpc-docs[\\/]" checks="SpringJavadoc" message="\@since" />
 	<suppress files="[\\/]spring-grpc-docs[\\/].*jooq" checks="AvoidStaticImport" />