Polish "Support expressing application `args` in `@SpringBootTest`"

Closes gh-14823

spring-boot-project/spring-boot-docs/src/main/asciidoc/spring-boot-features.adoc

@@ -6752,18 +6752,20 @@ NOTE: If you directly use `@ComponentScan` (that is, not through
 `@SpringBootApplication`) you need to register the `TypeExcludeFilter` with it. See
 {dc-spring-boot}/context/TypeExcludeFilter.{dc-ext}[the Javadoc] for details.
 
-[[boot-features-testing-spring-boot-applications-arguments]]
-==== Testing with Application Arguments
 
+
+[[boot-features-testing-spring-boot-application-arguments]]
+==== Using Application Arguments
 If your application expects <<boot-features-application-arguments,arguments>>, you can
-have `@SpringBootTest` inject them using the `args` field.
+have `@SpringBootTest` inject them using the `args` attribute.
 
 [source,java,indent=0]
 ----
-include::{test-examples}/context/ApplicationArgumentsExampleTests.java[tag=args]
-}
+include::{code-examples}/test/context/ApplicationArgumentsExampleTests.java[tag=example]
 ----
 
+
+
 [[boot-features-testing-spring-boot-applications-testing-with-mock-environment]]
 ==== Testing with a mock environment
 By default, `@SpringBootTest` does not start the server. If you have web endpoints that

spring-boot-project/spring-boot-docs/src/test/java/org/springframework/boot/docs/context/ApplicationArgumentsExampleTests.java → spring-boot-project/spring-boot-docs/src/main/java/org/springframework/boot/docs/test/context/ApplicationArgumentsExampleTests.java

 /*
- * Copyright 2012-2018 the original author or authors.
+ * Copyright 2012-2019 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.
@@ -14,22 +14,21 @@
  * limitations under the License.
  */
 
-package org.springframework.boot.docs.context;
+package org.springframework.boot.docs.test.context;
 
-// tag::args[]
 import org.junit.Test;
 import org.junit.runner.RunWith;
 
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.ApplicationArguments;
 import org.springframework.boot.test.context.SpringBootTest;
-import org.springframework.context.annotation.Configuration;
 import org.springframework.test.context.junit4.SpringRunner;
 
 import static org.assertj.core.api.Assertions.assertThat;
 
+// tag::example[]
 @RunWith(SpringRunner.class)
-@SpringBootTest(args = { "--foo=bar" })
+@SpringBootTest(args = "--app.test=one")
 public class ApplicationArgumentsExampleTests {
 
 	@Autowired
@@ -37,14 +36,9 @@ public class ApplicationArgumentsExampleTests {
 
 	@Test
 	public void applicationArgumentsPopulated() {
-		assertThat(this.args.getOptionNames()).contains("foo");
-		assertThat(this.args.getOptionValues("foo")).contains("bar");
-	}
-
-	// end::args[]
-	@Configuration
-	protected static class Config {
-
+		assertThat(this.args.getOptionNames()).containsOnly("app.test");
+		assertThat(this.args.getOptionValues("app.test")).containsOnly("one");
 	}
 
 }
+// end::example[]

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

 /*
- * Copyright 2012-2018 the original author or authors.
+ * Copyright 2012-2019 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.
@@ -146,11 +146,11 @@ public class SpringBootContextLoader extends AbstractContextLoader {
 	}
 
 	/**
-	 * Get the {@link SpringBootTest#args()} (if present) specified in the annotated test
-	 * class. If no args given, returns empty array.
+	 * Return the application arguments to use. If no arguments are available, return an
+	 * empty array.
 	 * @param config the source context configuration
-	 * @return the {@link SpringBootTest#args()} (if present) specified in the annotated
-	 * test class, or empty array
+	 * @return the application arguments to use
+	 * @see SpringApplication#run(String...)
 	 */
 	protected String[] getArgs(MergedContextConfiguration config) {
 		SpringBootTest annotation = AnnotatedElementUtils

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

 /*
- * Copyright 2012-2018 the original author or authors.
+ * Copyright 2012-2019 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.
@@ -25,6 +25,7 @@ import java.lang.annotation.Target;
 
 import org.junit.jupiter.api.extension.ExtendWith;
 
+import org.springframework.boot.ApplicationArguments;
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.SpringBootConfiguration;
 import org.springframework.boot.WebApplicationType;
@@ -55,6 +56,8 @@ import org.springframework.web.context.WebApplicationContext;
  * specified.</li>
  * <li>Allows custom {@link Environment} properties to be defined using the
  * {@link #properties() properties attribute}.</li>
+ * <li>Allows application arguments to be defined using the {@link #args() args
+ * attribute}.</li>
  * <li>Provides support for different {@link #webEnvironment() webEnvironment} modes,
  * including the ability to start a fully running web server listening on a
  * {@link WebEnvironment#DEFINED_PORT defined} or {@link WebEnvironment#RANDOM_PORT
@@ -93,6 +96,14 @@ public @interface SpringBootTest {
 	@AliasFor("value")
 	String[] properties() default {};
 
+	/**
+	 * Application arguments that should be passed to the application under test.
+	 * @return the application arguments to pass to the application under test.
+	 * @see ApplicationArguments
+	 * @see SpringApplication#run(String...)
+	 */
+	String[] args() default {};
+
 	/**
 	 * The <em>annotated classes</em> to use for loading an
 	 * {@link org.springframework.context.ApplicationContext ApplicationContext}. Can also
@@ -106,12 +117,6 @@ public @interface SpringBootTest {
 	 */
 	Class<?>[] classes() default {};
 
-	/**
-	 * Arguments that should be passed to the application under test.
-	 * @return the arguments to pass to the application under test.
-	 */
-	String[] args() default {};
-
 	/**
 	 * The type of web environment to create when applicable. Defaults to
 	 * {@link WebEnvironment#MOCK}.

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

 /*
- * Copyright 2012-2017 the original author or authors.
+ * Copyright 2012-2019 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.
@@ -27,13 +27,13 @@ import org.springframework.test.context.junit4.SpringRunner;
 import static org.assertj.core.api.Assertions.assertThat;
 
 /**
- * Assert that tests annotated with {@link SpringBootTest} can specify
- * {@link SpringBootTest#args()} to be passed to their application under test.
+ * Tests for {@link SpringBootTest} with application arguments.
  *
  * @author Justin Griffin
+ * @author Stephane Nicoll
  */
 @RunWith(SpringRunner.class)
-@SpringBootTest(args = { "--option.foo=option-foo-value", "other.bar=other-bar-value" })
+@SpringBootTest(args = { "--option.foo=foo-value", "other.bar=other-bar-value" })
 public class SpringBootTestArgsTests {
 
 	@Autowired
@@ -41,8 +41,10 @@ public class SpringBootTestArgsTests {
 
 	@Test
 	public void applicationArgumentsPopulated() {
-		assertThat(this.args.getOptionNames()).contains("option.foo");
-		assertThat(this.args.getNonOptionArgs()).contains("other.bar=other-bar-value");
+		assertThat(this.args.getOptionNames()).containsOnly("option.foo");
+		assertThat(this.args.getOptionValues("option.foo")).containsOnly("foo-value");
+		assertThat(this.args.getNonOptionArgs())
+				.containsOnly("other.bar=other-bar-value");
 	}
 
 	@Configuration