GH-1300 Add test for post processing Kotlin functions

Author: olegz

spring-cloud-function-kotlin/src/test/java/org/springframework/cloud/function/kotlin/ContextFunctionCatalogAutoConfigurationKotlinTests.java

@@ -29,6 +29,7 @@
 import org.springframework.cloud.function.context.FunctionCatalog;
 import org.springframework.cloud.function.context.catalog.FunctionTypeUtils;
 import org.springframework.cloud.function.context.catalog.SimpleFunctionRegistry.FunctionInvocationWrapper;
+import org.springframework.cloud.function.context.config.KotlinLambdaToFunctionAutoConfiguration;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.context.support.GenericApplicationContext;
@@ -59,11 +60,21 @@ public void typeDiscoveryTests() {
 		create(new Class[] { KotlinLambdasConfiguration.class,
 				SimpleConfiguration.class,
 				KotlinComponentFunction.class,
+				KotlinPostProcessingFunction.class,
 				ComponentUppercase.class,
 				ComponentWithUnitReturn.class});
 
 		FunctionCatalog functionCatalog = this.context.getBean(FunctionCatalog.class);
 
+		// Test post-processing logic
+		FunctionInvocationWrapper kotlinPostProcessingFunction = functionCatalog.lookup("kotlinPostProcessingFunction");
+		kotlinPostProcessingFunction.apply("bob");
+		kotlinPostProcessingFunction.postProcess();
+		KotlinPostProcessingFunction postProcessingFunction =  (KotlinPostProcessingFunction)
+			((KotlinLambdaToFunctionAutoConfiguration.KotlinFunctionWrapper) kotlinPostProcessingFunction.getTarget()).getKotlinLambdaTarget();
+		assertThat(postProcessingFunction.getInvoked()).isTrue();
+		// End test post-processing logic
+
 		FunctionInvocationWrapper kotlinComponentFunction = functionCatalog.lookup("kotlinComponentFunction");
 		assertThat(kotlinComponentFunction.isFunction()).isTrue();
 		assertThat(kotlinComponentFunction.getInputType().getTypeName()).isEqualTo("java.lang.String");

spring-cloud-function-kotlin/src/test/kotlin/org/springframework/cloud/function/kotlin/KotlinPostProcessingFunction.kt

@@ -0,0 +1,20 @@
+package org.springframework.cloud.function.kotlin
+
+import org.springframework.cloud.function.context.PostProcessingFunction
+import org.springframework.messaging.Message
+import org.springframework.stereotype.Component
+import java.util.function.Function
+
+@Component
+class KotlinPostProcessingFunction : PostProcessingFunction<String, String> {
+
+	var invoked = false
+
+	override fun apply(t: String): String {
+		return t.uppercase();
+	}
+
+	override fun postProcess(result: Message<String>?) {
+		invoked = true;
+	}
+}