Honor spring.autoconfigure.exclude in test slices

Previously, the import selector for `@ImportAutoConfiguration` did not
consider the spring.autoconfigure.exclude property when determining
which auto-configurations to exclude. This meant that tests using a
slice that included a particular auto-configuration would include it
even if the application's configuration excluded it via
spring.autoconfigure.exclude. Confusingly, this could result in a
sliced test using an auto-configuration that would be excluded in a
broader `@SpringBootTest`.

This commit updates the ImportAutoConfigurationImportSelector to
consider the spring.autoconfigure.exclude property so that sliced tests
will use a subset of the auto-configurations that a `@SpringBootTest`
would use.

Fixes gh-21736

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/AutoConfigurationImportSelector.java

@@ -233,13 +233,23 @@ public class AutoConfigurationImportSelector implements DeferredImportSelector,
 		return excluded;
 	}
 
-	private List<String> getExcludeAutoConfigurationsProperty() {
-		if (getEnvironment() instanceof ConfigurableEnvironment) {
-			Binder binder = Binder.get(getEnvironment());
+	/**
+	 * Returns the auto-configurations excluded by the
+	 * {@code spring.autoconfigure.exclude} property.
+	 * @return excluded auto-configurations
+	 * @since 2.3.2
+	 */
+	protected List<String> getExcludeAutoConfigurationsProperty() {
+		Environment environment = getEnvironment();
+		if (environment == null) {
+			return Collections.emptyList();
+		}
+		if (environment instanceof ConfigurableEnvironment) {
+			Binder binder = Binder.get(environment);
 			return binder.bind(PROPERTY_NAME_AUTOCONFIGURE_EXCLUDE, String[].class).map(Arrays::asList)
 					.orElse(Collections.emptyList());
 		}
-		String[] excludes = getEnvironment().getProperty(PROPERTY_NAME_AUTOCONFIGURE_EXCLUDE, String[].class);
+		String[] excludes = environment.getProperty(PROPERTY_NAME_AUTOCONFIGURE_EXCLUDE, String[].class);
 		return (excludes != null) ? Arrays.asList(excludes) : Collections.emptyList();
 	}
 

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/ImportAutoConfigurationImportSelector.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2020 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.
@@ -118,6 +118,7 @@ class ImportAutoConfigurationImportSelector extends AutoConfigurationImportSelec
 				}
 			}
 		}
+		exclusions.addAll(getExcludeAutoConfigurationsProperty());
 		return exclusions;
 	}
 

spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/ImportAutoConfigurationImportSelectorTests.java

@@ -25,22 +25,19 @@ import java.util.Set;
 
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
-import org.mockito.Mock;
-import org.mockito.MockitoAnnotations;
 
 import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
 import org.springframework.beans.factory.support.DefaultListableBeanFactory;
 import org.springframework.boot.autoconfigure.freemarker.FreeMarkerAutoConfiguration;
 import org.springframework.boot.autoconfigure.thymeleaf.ThymeleafAutoConfiguration;
 import org.springframework.core.annotation.AliasFor;
-import org.springframework.core.env.Environment;
 import org.springframework.core.io.DefaultResourceLoader;
 import org.springframework.core.type.AnnotationMetadata;
 import org.springframework.core.type.classreading.SimpleMetadataReaderFactory;
+import org.springframework.mock.env.MockEnvironment;
 import org.springframework.util.ClassUtils;
 
 import static org.assertj.core.api.Assertions.assertThat;
-import static org.mockito.Mockito.verifyNoInteractions;
 
 /**
  * Tests for {@link ImportAutoConfigurationImportSelector}.
@@ -54,12 +51,10 @@ class ImportAutoConfigurationImportSelectorTests {
 
 	private final ConfigurableListableBeanFactory beanFactory = new DefaultListableBeanFactory();
 
-	@Mock
-	private Environment environment;
+	private final MockEnvironment environment = new MockEnvironment();
 
 	@BeforeEach
 	void setup() {
-		MockitoAnnotations.initMocks(this);
 		this.importSelector.setBeanFactory(this.beanFactory);
 		this.importSelector.setEnvironment(this.environment);
 		this.importSelector.setResourceLoader(new DefaultResourceLoader());
@@ -80,10 +75,11 @@ class ImportAutoConfigurationImportSelectorTests {
 	}
 
 	@Test
-	void propertyExclusionsAreNotApplied() throws Exception {
-		AnnotationMetadata annotationMetadata = getAnnotationMetadata(ImportFreeMarker.class);
-		this.importSelector.selectImports(annotationMetadata);
-		verifyNoInteractions(this.environment);
+	void propertyExclusionsAreApplied() throws IOException {
+		this.environment.setProperty("spring.autoconfigure.exclude", FreeMarkerAutoConfiguration.class.getName());
+		AnnotationMetadata annotationMetadata = getAnnotationMetadata(MultipleImports.class);
+		String[] imports = this.importSelector.selectImports(annotationMetadata);
+		assertThat(imports).containsExactly(ThymeleafAutoConfiguration.class.getName());
 	}
 
 	@Test
@@ -288,7 +284,9 @@ class ImportAutoConfigurationImportSelectorTests {
 	@interface MetaImportAutoConfiguration {
 
 		@AliasFor(annotation = ImportAutoConfiguration.class)
-		Class<?>[] exclude() default {};
+		Class<?>[] exclude() default {
+
+		};
 
 	}
 
@@ -308,7 +306,9 @@ class ImportAutoConfigurationImportSelectorTests {
 	@interface SelfAnnotating {
 
 		@AliasFor(annotation = ImportAutoConfiguration.class, attribute = "exclude")
-		Class<?>[] excludeAutoConfiguration() default {};
+		Class<?>[] excludeAutoConfiguration() default {
+
+		};
 
 	}