Introduce @Nested tests with constructor injection

This commit introduces @Nested tests to verify support for constructor
injection when using the SpringExtension.

One of the tests is disabled on Java 8 due to a bug in javac that was
first fixed in JDK 9.

See https://github.com/junit-team/junit5/issues/1345 for details.

spring-test/src/test/java/org/springframework/test/context/junit/jupiter/nested/NestedTestsWithConstructorInjectionWithSpringAndJUnitJupiterTestCase.java

@@ -0,0 +1,124 @@
+/*
+ * Copyright 2002-2018 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
+ *
+ *      http://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.test.context.junit.jupiter.nested;
+
+import org.junit.jupiter.api.Nested;
+import org.junit.jupiter.api.Test;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.test.context.junit.SpringJUnitJupiterTestSuite;
+import org.springframework.test.context.junit.jupiter.DisabledIf;
+import org.springframework.test.context.junit.jupiter.SpringExtension;
+import org.springframework.test.context.junit.jupiter.SpringJUnitConfig;
+import org.springframework.test.context.junit.jupiter.nested.NestedTestsWithConstructorInjectionWithSpringAndJUnitJupiterTestCase.TopLevelConfig;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+/**
+ * Integration tests that verify support for {@code @Nested} test classes in conjunction
+ * with the {@link SpringExtension} in a JUnit Jupiter environment ... when using
+ * constructor injection as opposed to field injection.
+ *
+ * <p>
+ * To run these tests in an IDE that does not have built-in support for the JUnit
+ * Platform, simply run {@link SpringJUnitJupiterTestSuite} as a JUnit 4 test.
+ *
+ * @author Sam Brannen
+ * @since 5.0.5
+ * @see NestedTestsWithSpringAndJUnitJupiterTestCase
+ * @see org.springframework.test.context.junit4.nested.NestedTestsWithSpringRulesTests
+ */
+@SpringJUnitConfig(TopLevelConfig.class)
+class NestedTestsWithConstructorInjectionWithSpringAndJUnitJupiterTestCase {
+
+	final String foo;
+
+	@Autowired
+	NestedTestsWithConstructorInjectionWithSpringAndJUnitJupiterTestCase(String foo) {
+		this.foo = foo;
+	}
+
+	@Test
+	void topLevelTest() {
+		assertEquals("foo", foo);
+	}
+
+	@Nested
+	@SpringJUnitConfig(NestedConfig.class)
+	class AutowiredConstructor {
+
+		final String bar;
+
+		// Only fails on JDK 8 if the parameter is annotated with @Autowired.
+		// Works if the constructor itself is annotated with @Autowired.
+		@Autowired
+		AutowiredConstructor(String bar) {
+			this.bar = bar;
+		}
+
+		@Test
+		void nestedTest() throws Exception {
+			assertEquals("foo", foo);
+			assertEquals("bar", bar);
+		}
+	}
+
+	@Nested
+	@SpringJUnitConfig(NestedConfig.class)
+	@DisabledIf(expression = "#{systemProperties['java.version'].startsWith('1.8')}", //
+			reason = "Disabled on Java 8 due to a bug in javac in JDK 8")
+	// See https://github.com/junit-team/junit5/issues/1345
+	class AutowiredConstructorParameter {
+
+		final String bar;
+
+		// Only fails on JDK 8 if the parameter is annotated with @Autowired.
+		// Works if the constructor itself is annotated with @Autowired.
+		AutowiredConstructorParameter(@Autowired String bar) {
+			this.bar = bar;
+		}
+
+		@Test
+		void nestedTest() throws Exception {
+			assertEquals("foo", foo);
+			assertEquals("bar", bar);
+		}
+	}
+
+	// -------------------------------------------------------------------------
+
+	@Configuration
+	static class TopLevelConfig {
+
+		@Bean
+		String foo() {
+			return "foo";
+		}
+	}
+
+	@Configuration
+	static class NestedConfig {
+
+		@Bean
+		String bar() {
+			return "bar";
+		}
+	}
+
+}

spring-test/src/test/java/org/springframework/test/context/junit/jupiter/nested/NestedTestsWithSpringAndJUnitJupiterTestCase.java

@@ -38,6 +38,7 @@ import static org.junit.jupiter.api.Assertions.assertEquals;
  *
  * @author Sam Brannen
  * @since 5.0
+ * @see NestedTestsWithConstructorInjectionWithSpringAndJUnitJupiterTestCase
  * @see org.springframework.test.context.junit4.nested.NestedTestsWithSpringRulesTests
  */
 @SpringJUnitConfig(TopLevelConfig.class)