GH-602 Ensure collections with converted items are not converted again

Resolves #602

spring-cloud-function-context/src/test/java/org/springframework/cloud/function/userissues/UserIssuesTests.java

@@ -0,0 +1,122 @@
+/*
+ * Copyright 2020-2020 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.
+ * 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.cloud.function.userissues;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.function.Function;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
+import org.springframework.boot.builder.SpringApplicationBuilder;
+import org.springframework.cloud.function.context.FunctionCatalog;
+import org.springframework.context.ApplicationContext;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.messaging.Message;
+import org.springframework.messaging.support.GenericMessage;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ *
+ * @author Oleg Zhurakousky
+ *
+ */
+public class UserIssuesTests {
+
+	private FunctionCatalog configureCatalog(Class<?>... configClass) {
+		ApplicationContext context = new SpringApplicationBuilder(configClass).run(
+				"--logging.level.org.springframework.cloud.function=DEBUG", "--spring.main.lazy-initialization=true");
+		FunctionCatalog catalog = context.getBean(FunctionCatalog.class);
+		return catalog;
+	}
+
+	@BeforeEach
+	public void before() {
+		System.clearProperty("spring.cloud.function.definition");
+	}
+
+	@Test
+	public void testIssue602() throws Exception {
+		FunctionCatalog catalog = this.configureCatalog(Issue602Configuration.class);
+		Function<Message<String>, Integer> function = catalog.lookup("consumer");
+		int result = function.apply(
+				new GenericMessage<String>("[{\"name\":\"julien\"},{\"name\":\"ricky\"},{\"name\":\"bubbles\"}]"));
+		assertThat(result).isEqualTo(3);
+	}
+
+	@Test
+	public void testIssue602asPOJO() throws Exception {
+		FunctionCatalog catalog = this.configureCatalog(Issue602Configuration.class);
+		Function<Message<List<Product>>, Integer> function = catalog.lookup("consumer");
+		ArrayList<Product> products = new ArrayList<>();
+		Product p = new Product();
+		p.setName("julien");
+		products.add(p);
+		p = new Product();
+		p.setName("ricky");
+		products.add(p);
+		p = new Product();
+		p.setName("bubbles");
+		products.add(p);
+		int result = function.apply(new GenericMessage<List<Product>>(products));
+		assertThat(result).isEqualTo(3);
+
+	}
+
+	@Test
+	public void testIssue602asCollectionOfUnconvertedItems() throws Exception {
+		FunctionCatalog catalog = this.configureCatalog(Issue602Configuration.class);
+		Function<Message<List<String>>, Integer> function = catalog.lookup("consumer");
+		ArrayList<String> products = new ArrayList<>();
+		products.add("{\"name\":\"julien\"}");
+		products.add("{\"name\":\"ricky\"}");
+		products.add("{\"name\":\"bubbles\"}");
+		int result = function.apply(new GenericMessage<List<String>>(products));
+		assertThat(result).isEqualTo(3);
+
+	}
+
+	@EnableAutoConfiguration
+	@Configuration
+	public static class Issue602Configuration {
+		@Bean
+		public Function<List<Product>, Integer> consumer() {
+			return v -> {
+				assertThat(v.get(0).getName()).isEqualTo("julien");
+				assertThat(v.get(1).getName()).isEqualTo("ricky");
+				assertThat(v.get(2).getName()).isEqualTo("bubbles");
+				return v.size();
+			};
+		}
+	}
+
+	public static class Product {
+		private String name;
+
+		public String getName() {
+			return name;
+		}
+
+		public void setName(String name) {
+			this.name = name;
+		}
+	}
+}