Test that TestBean can override a ConfigurationProperties bean

Closes gh-33969

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/context/properties/ConfigurationPropertiesTestBeanTests.java

@@ -0,0 +1,82 @@
+/*
+ * Copyright 2012-2024 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.boot.context.properties;
+
+import org.junit.jupiter.api.Test;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.test.context.TestPropertySource;
+import org.springframework.test.context.bean.override.convention.TestBean;
+import org.springframework.test.context.junit.jupiter.SpringJUnitConfig;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Tests for overriding {@link ConfigurationProperties @ConfigurationProperties} with
+ * {@link TestBean @TestBean}.
+ *
+ * @author Andy Wilkinson
+ */
+@SpringJUnitConfig
+@TestPropertySource(properties = "immutable.property=test-property-source")
+class ConfigurationPropertiesTestBeanTests {
+
+	@TestBean
+	private ImmutableProperties properties;
+
+	@Autowired
+	private SomeConfiguration someConfiguration;
+
+	@Test
+	void propertiesCanBeOverriddenUsingTestBean() {
+		assertThat(this.properties.property).isEqualTo("test-bean");
+		assertThat(this.someConfiguration.properties.property).isEqualTo("test-bean");
+	}
+
+	static ImmutableProperties properties() {
+		return new ImmutableProperties("test-bean");
+	}
+
+	@Configuration(proxyBeanMethods = false)
+	@EnableConfigurationProperties(ImmutableProperties.class)
+	static class SomeConfiguration {
+
+		private final ImmutableProperties properties;
+
+		SomeConfiguration(ImmutableProperties properties) {
+			this.properties = properties;
+		}
+
+	}
+
+	@ConfigurationProperties("immutable")
+	static class ImmutableProperties {
+
+		private final String property;
+
+		ImmutableProperties(String property) {
+			this.property = property;
+		}
+
+		String getProperty() {
+			return this.property;
+		}
+
+	}
+
+}