Add YamlPropertySourceFactory that can be used for loading YAML files…

… through the @TestPropertySource annotation.

spring-boot-project/spring-boot-test/build.gradle

@@ -59,5 +59,5 @@ dependencies {
 	testImplementation("org.testng:testng")
 
 	testRuntimeOnly("org.junit.vintage:junit-vintage-engine")
+	testRuntimeOnly("org.yaml:snakeyaml")
 }
-

spring-boot-project/spring-boot-test/src/main/java/org/springframework/boot/test/context/YamlPropertySourceFactory.java

@@ -0,0 +1,72 @@
+/*
+ * 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.test.context;
+
+import java.io.IOException;
+import java.util.List;
+
+import org.springframework.boot.env.YamlPropertySourceLoader;
+import org.springframework.core.env.CompositePropertySource;
+import org.springframework.core.env.PropertySource;
+import org.springframework.core.io.Resource;
+import org.springframework.core.io.support.EncodedResource;
+import org.springframework.core.io.support.PropertySourceFactory;
+import org.springframework.util.StringUtils;
+
+/**
+ * An implementation of {@link PropertySourceFactory} that delegates the loading of
+ * {@code PropertySource} to {@link YamlPropertySourceLoader}. If the provided YAML file
+ * contains multiple documents (separated by {@code ---}), the property sources from later
+ * documents will take precedence, overriding any conflicting values defined in earlier
+ * documents.
+ *
+ * @author Dmytro Nosan
+ * @since 3.4.0
+ */
+public class YamlPropertySourceFactory implements PropertySourceFactory {
+
+	private final YamlPropertySourceLoader loader = new YamlPropertySourceLoader();
+
+	@Override
+	public PropertySource<?> createPropertySource(String name, EncodedResource encodedResource) throws IOException {
+		Resource resource = encodedResource.getResource();
+		String propertySourceName = getPropertySourceName(name, resource);
+		List<PropertySource<?>> propertySources = this.loader.load(propertySourceName, resource);
+		return new YamlCompositePropertySource(propertySourceName, propertySources);
+	}
+
+	private static String getPropertySourceName(String name, Resource resource) {
+		if (StringUtils.hasText(name)) {
+			return name;
+		}
+		String description = resource.getDescription();
+		if (StringUtils.hasText(description)) {
+			return description;
+		}
+		return resource.getClass().getSimpleName() + "@" + System.identityHashCode(resource);
+	}
+
+	private static final class YamlCompositePropertySource extends CompositePropertySource {
+
+		YamlCompositePropertySource(String name, List<PropertySource<?>> propertySources) {
+			super(name);
+			propertySources.forEach(this::addFirstPropertySource);
+		}
+
+	}
+
+}

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

@@ -0,0 +1,55 @@
+/*
+ * 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.test.context;
+
+import org.junit.jupiter.api.Test;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.core.env.Environment;
+import org.springframework.test.context.TestPropertySource;
+import org.springframework.test.context.junit.jupiter.SpringJUnitConfig;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Integration tests for {@link YamlPropertySourceFactory} with
+ * {@link TestPropertySource}.
+ *
+ * @author Dmytro Nosan
+ */
+@SpringJUnitConfig
+@TestPropertySource(locations = { "classpath:test.yaml", "classpath:test1.yaml" },
+		factory = YamlPropertySourceFactory.class)
+class YamlPropertySourceFactoryIntegrationTests {
+
+	@Autowired
+	private Environment environment;
+
+	@Test
+	void loadProperties() {
+		assertThat(this.environment.getProperty("spring.bar")).isEqualTo("bar");
+		assertThat(this.environment.getProperty("spring.foo")).isEqualTo("baz");
+		assertThat(this.environment.getProperty("spring.buzz")).isEqualTo("fazz");
+	}
+
+	@Configuration(proxyBeanMethods = false)
+	static class Config {
+
+	}
+
+}

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

@@ -0,0 +1,70 @@
+/*
+ * 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.test.context;
+
+import java.io.IOException;
+
+import org.junit.jupiter.api.Test;
+
+import org.springframework.core.env.PropertySource;
+import org.springframework.core.io.ClassPathResource;
+import org.springframework.core.io.support.EncodedResource;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.BDDMockito.willReturn;
+import static org.mockito.Mockito.spy;
+
+/**
+ * Tests for {@link YamlPropertySourceFactory}.
+ *
+ * @author Dmytro Nosan
+ */
+class YamlPropertySourceFactoryTests {
+
+	private final YamlPropertySourceFactory factory = new YamlPropertySourceFactory();
+
+	@Test
+	void shouldCreatePropertySourceWithYamlPropertySourceLoaderWithGivenName() throws IOException {
+		EncodedResource resource = new EncodedResource(new ClassPathResource("test.yaml"));
+		PropertySource<?> propertySource = this.factory.createPropertySource("test", resource);
+		assertThat(propertySource.getName()).isEqualTo("test");
+		assertProperties(propertySource);
+	}
+
+	@Test
+	void shouldCreatePropertySourceWithYamlPropertySourceLoaderWithResourceDescriptionName() throws IOException {
+		EncodedResource resource = new EncodedResource(new ClassPathResource("test.yaml"));
+		PropertySource<?> propertySource = this.factory.createPropertySource(null, resource);
+		assertThat(propertySource.getName()).isEqualTo("class path resource [test.yaml]");
+		assertProperties(propertySource);
+	}
+
+	@Test
+	void shouldCreatePropertySourceWithYamlPropertySourceLoaderWithGeneratedName() throws IOException {
+		ClassPathResource resource = spy(new ClassPathResource("test.yaml"));
+		willReturn(null).given(resource).getDescription();
+		PropertySource<?> propertySource = this.factory.createPropertySource(null, new EncodedResource(resource));
+		assertThat(propertySource.getName()).startsWith("ClassPathResource@");
+		assertProperties(propertySource);
+	}
+
+	private static void assertProperties(PropertySource<?> propertySource) {
+		assertThat(propertySource.getProperty("spring.bar")).isEqualTo("bar");
+		assertThat(propertySource.getProperty("spring.foo")).isEqualTo("baz");
+	}
+
+}

spring-boot-project/spring-boot-test/src/test/resources/test.yaml

@@ -0,0 +1,6 @@
+spring:
+  bar: foo
+---
+spring:
+  bar: bar
+  foo: baz

spring-boot-project/spring-boot-test/src/test/resources/test1.yaml

@@ -0,0 +1,2 @@
+spring:
+  buzz: fazz