Test Spring-managed JUnit Jupiter extension

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

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+/*
+ * 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;
+
+import java.util.Collections;
+import java.util.List;
+import java.util.stream.Stream;
+
+import org.junit.jupiter.api.TestInstance;
+import org.junit.jupiter.api.TestInstance.Lifecycle;
+import org.junit.jupiter.api.TestTemplate;
+import org.junit.jupiter.api.extension.Extension;
+import org.junit.jupiter.api.extension.ExtensionContext;
+import org.junit.jupiter.api.extension.ParameterContext;
+import org.junit.jupiter.api.extension.ParameterResolver;
+import org.junit.jupiter.api.extension.RegisterExtension;
+import org.junit.jupiter.api.extension.TestTemplateInvocationContext;
+import org.junit.jupiter.api.extension.TestTemplateInvocationContextProvider;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+/**
+ * This class demonstrates how to have a JUnit Jupiter extension managed as a
+ * Spring bean in order to have dependencies injected into an extension from
+ * a Spring {@code ApplicationContext}.
+ *
+ * @author Sam Brannen
+ * @since 5.1
+ */
+@SpringJUnitConfig
+@TestInstance(Lifecycle.PER_CLASS)
+class SpringManagedJupiterExtensionTests {
+
+	@Autowired
+	@RegisterExtension
+	TestTemplateInvocationContextProvider provider;
+
+
+	@TestTemplate
+	void testTemplate(String parameter) {
+		assertTrue("foo".equals(parameter) || "bar".equals(parameter));
+	}
+
+
+	@Configuration
+	static class Config {
+
+		@Bean
+		String foo() {
+			return "foo";
+		}
+
+		@Bean
+		String bar() {
+			return "bar";
+		}
+
+		@Bean
+		TestTemplateInvocationContextProvider provider(List<String> parameters) {
+			return new StringInvocationContextProvider(parameters);
+		}
+	}
+
+	private static class StringInvocationContextProvider implements TestTemplateInvocationContextProvider {
+
+		private final List<String> parameters;
+
+
+		StringInvocationContextProvider(List<String> parameters) {
+			this.parameters = parameters;
+		}
+
+		@Override
+		public boolean supportsTestTemplate(ExtensionContext context) {
+			return true;
+		}
+
+		@Override
+		public Stream<TestTemplateInvocationContext> provideTestTemplateInvocationContexts(ExtensionContext context) {
+			return this.parameters.stream().map(this::invocationContext);
+		}
+
+		private TestTemplateInvocationContext invocationContext(String parameter) {
+			return new TestTemplateInvocationContext() {
+
+				@Override
+				public String getDisplayName(int invocationIndex) {
+					return parameter;
+				}
+
+				@Override
+				public List<Extension> getAdditionalExtensions() {
+					return Collections.singletonList(new ParameterResolver() {
+
+						@Override
+						public boolean supportsParameter(ParameterContext parameterContext,
+								ExtensionContext extensionContext) {
+							return parameterContext.getParameter().getType() == String.class;
+						}
+
+						@Override
+						public Object resolveParameter(ParameterContext parameterContext,
+								ExtensionContext extensionContext) {
+							return parameter;
+						}
+					});
+				}
+			};
+		}
+	}
+
+}