test: Pojo serializer

Author: maxday

aws-lambda-java-runtime-interface-client/src/test/java/com/amazonaws/services/lambda/runtime/api/client/PojoSerializerLoaderTest.java

@@ -0,0 +1,151 @@
+/*
+Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+SPDX-License-Identifier: Apache-2.0
+*/
+
+package com.amazonaws.services.lambda.runtime.api.client;
+
+import com.amazonaws.services.lambda.runtime.CustomPojoSerializer;
+import com.amazonaws.services.lambda.runtime.serialization.PojoSerializer;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.Mock;
+import org.mockito.junit.jupiter.MockitoExtension;
+
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.lang.reflect.Field;
+import java.lang.reflect.Type;
+
+import static org.junit.jupiter.api.Assertions.*;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.eq;
+import static org.mockito.Mockito.*;
+
+@ExtendWith(MockitoExtension.class)
+class PojoSerializerLoaderTest {
+
+    @Mock
+    private CustomPojoSerializer mockSerializer;
+
+    @BeforeEach
+    void setUp() throws Exception {
+        resetStaticFields();
+    }
+
+    private void resetStaticFields() throws Exception {
+        Field serializerField = PojoSerializerLoader.class.getDeclaredField("customPojoSerializer");
+        serializerField.setAccessible(true);
+        serializerField.set(null, null);
+
+        Field initializedField = PojoSerializerLoader.class.getDeclaredField("initialized");
+        initializedField.setAccessible(true);
+        initializedField.set(null, false);
+    }
+
+
+    private void setMockSerializer(CustomPojoSerializer serializer) throws Exception {
+        Field serializerField = PojoSerializerLoader.class.getDeclaredField("customPojoSerializer");
+        serializerField.setAccessible(true);
+        serializerField.set(null, serializer);
+    }
+
+    @Test
+    void testGetCustomerSerializerNoSerializerAvailable() throws Exception {
+        PojoSerializer<Object> serializer = PojoSerializerLoader.getCustomerSerializer(String.class);
+        assertNull(serializer);
+        Field initializedField = PojoSerializerLoader.class.getDeclaredField("initialized");
+        initializedField.setAccessible(true);
+        assert((Boolean) initializedField.get(null));
+    }
+
+    @Test
+    void testGetCustomerSerializerWithValidSerializer() throws Exception {
+        setMockSerializer(mockSerializer);
+        String testInput = "test input";
+        String testOutput = "test output";
+        Type testType = String.class;
+        when(mockSerializer.fromJson(any(InputStream.class), eq(testType))).thenReturn(testOutput);
+        when(mockSerializer.fromJson(eq(testInput), eq(testType))).thenReturn(testOutput);
+
+        PojoSerializer<Object> serializer = PojoSerializerLoader.getCustomerSerializer(testType);
+        assertNotNull(serializer);
+
+        ByteArrayInputStream inputStream = new ByteArrayInputStream(testInput.getBytes());
+        Object result1 = serializer.fromJson(inputStream);
+        assertEquals(testOutput, result1);
+    
+        Object result2 = serializer.fromJson(testInput);
+        assertEquals(testOutput, result2);
+
+        ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
+        serializer.toJson(testInput, outputStream);
+        verify(mockSerializer).toJson(eq(testInput), any(OutputStream.class), eq(testType));
+    }
+
+    @Test
+    void testGetCustomerSerializerCachingBehavior() throws Exception {
+        setMockSerializer(mockSerializer);
+
+        Type testType = String.class;
+        PojoSerializer<Object> serializer1 = PojoSerializerLoader.getCustomerSerializer(testType);
+        PojoSerializer<Object> serializer2 = PojoSerializerLoader.getCustomerSerializer(testType);
+
+        assertNotNull(serializer1);
+        assertNotNull(serializer2);
+        
+        String testInput = "test";
+        serializer1.fromJson(testInput);
+        serializer2.fromJson(testInput);
+        
+        verify(mockSerializer, times(2)).fromJson(eq(testInput), eq(testType));
+    }
+
+    @Test
+    void testGetCustomerSerializerDifferentTypes() throws Exception {
+        setMockSerializer(mockSerializer);
+
+        PojoSerializer<Object> stringSerializer = PojoSerializerLoader.getCustomerSerializer(String.class);
+        PojoSerializer<Object> integerSerializer = PojoSerializerLoader.getCustomerSerializer(Integer.class);
+
+        assertNotNull(stringSerializer);
+        assertNotNull(integerSerializer);
+
+        String testString = "test";
+        Integer testInt = 123;
+
+        stringSerializer.fromJson(testString);
+        integerSerializer.fromJson(testInt.toString());
+
+        verify(mockSerializer).fromJson(eq(testString), eq(String.class));
+        verify(mockSerializer).fromJson(eq(testInt.toString()), eq(Integer.class));
+    }
+
+    @Test
+    void testGetCustomerSerializerNullType() throws Exception {
+        setMockSerializer(mockSerializer);
+
+        PojoSerializer<Object> serializer = PojoSerializerLoader.getCustomerSerializer(null);
+        assertNotNull(serializer);
+
+        String testInput = "test";
+        serializer.fromJson(testInput);
+        verify(mockSerializer).fromJson(eq(testInput), eq(null));
+    }
+
+    @Test
+    void testGetCustomerSerializerExceptionHandling() throws Exception {
+        setMockSerializer(mockSerializer);
+
+        doThrow(new RuntimeException("Test exception"))
+            .when(mockSerializer)
+            .fromJson(any(String.class), any(Type.class));
+
+        PojoSerializer<Object> serializer = PojoSerializerLoader.getCustomerSerializer(String.class);
+        assertNotNull(serializer);
+        assertThrows(RuntimeException.class, () -> serializer.fromJson("test"));
+    }
+}