diff --git a/aws-lambda-java-runtime-interface-client/src/test/java/com/amazonaws/services/lambda/runtime/api/client/runtimeapi/converters/LambdaErrorConverterTest.java b/aws-lambda-java-runtime-interface-client/src/test/java/com/amazonaws/services/lambda/runtime/api/client/runtimeapi/converters/LambdaErrorConverterTest.java
new file mode 100644
index 00000000..f94bc0c5
--- /dev/null
+++ b/aws-lambda-java-runtime-interface-client/src/test/java/com/amazonaws/services/lambda/runtime/api/client/runtimeapi/converters/LambdaErrorConverterTest.java
@@ -0,0 +1,112 @@
+/*
+Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+SPDX-License-Identifier: Apache-2.0
+*/
+package com.amazonaws.services.lambda.runtime.api.client.runtimeapi.converters;
+
+import com.amazonaws.services.lambda.runtime.api.client.UserFault;
+import com.amazonaws.services.lambda.runtime.api.client.runtimeapi.dto.ErrorRequest;
+import org.junit.jupiter.api.Test;
+import static org.junit.jupiter.api.Assertions.*;
+
+class LambdaErrorConverterTest {
+
+    @Test
+    void testFromUserFaultWithMessageAndException() {
+        UserFault userFault = new UserFault("Test error message", "TestException", "Test stack trace");
+        ErrorRequest errorRequest = LambdaErrorConverter.fromUserFault(userFault);
+        
+        assertNotNull(errorRequest);
+        assertEquals("Test error message", errorRequest.errorMessage);
+        assertEquals("TestException", errorRequest.errorType);
+        assertNull(errorRequest.stackTrace);
+    }
+
+    @Test
+    void testFromUserFaultWithNullValues() {
+        UserFault userFault = new UserFault(null, null, null);
+        ErrorRequest errorRequest = LambdaErrorConverter.fromUserFault(userFault);
+        
+        assertNotNull(errorRequest);
+        assertNull(errorRequest.errorMessage);
+        assertNull(errorRequest.errorType);
+        assertNull(errorRequest.stackTrace);
+    }
+
+    @Test
+    void testFromUserFaultWithFatalError() {
+        UserFault userFault = new UserFault("Fatal error", "FatalException", "Test stack trace", true);
+        ErrorRequest errorRequest = LambdaErrorConverter.fromUserFault(userFault);
+        
+        assertNotNull(errorRequest);
+        assertEquals("Fatal error", errorRequest.errorMessage);
+        assertEquals("FatalException", errorRequest.errorType);
+        assertNull(errorRequest.stackTrace);
+    }
+
+    @Test
+    void testFromUserFaultCreatedFromException() {
+        Exception exception = new RuntimeException("Test exception message");
+        UserFault userFault = UserFault.makeUserFault(exception);
+        ErrorRequest errorRequest = LambdaErrorConverter.fromUserFault(userFault);
+        
+        assertNotNull(errorRequest);
+        assertEquals("Test exception message", errorRequest.errorMessage);
+        assertEquals("java.lang.RuntimeException", errorRequest.errorType);
+        assertNull(errorRequest.stackTrace);
+    }
+
+    @Test
+    void testFromUserFaultCreatedFromMessage() {
+        UserFault userFault = UserFault.makeUserFault("Simple message");
+        ErrorRequest errorRequest = LambdaErrorConverter.fromUserFault(userFault);
+        
+        assertNotNull(errorRequest);
+        assertEquals("Simple message", errorRequest.errorMessage);
+        assertNull(errorRequest.errorType);
+        assertNull(errorRequest.stackTrace);
+    }
+
+    @Test
+    void testFromThrowableWithMessage() {
+        Exception exception = new RuntimeException("Test exception message");
+        ErrorRequest errorRequest = LambdaErrorConverter.fromThrowable(exception);
+        
+        assertNotNull(errorRequest);
+        assertEquals("Test exception message", errorRequest.errorMessage);
+        assertEquals("java.lang.RuntimeException", errorRequest.errorType);
+        assertNotNull(errorRequest.stackTrace);
+        assertTrue(errorRequest.stackTrace.length > 0);
+    }
+
+    @Test
+    void testFromThrowableWithNullMessage() {
+        Exception exception = new RuntimeException();
+        ErrorRequest errorRequest = LambdaErrorConverter.fromThrowable(exception);
+        
+        assertNotNull(errorRequest);
+        assertEquals("java.lang.RuntimeException", errorRequest.errorMessage);
+        assertEquals("java.lang.RuntimeException", errorRequest.errorType);
+        assertNotNull(errorRequest.stackTrace);
+        assertTrue(errorRequest.stackTrace.length > 0);
+    }
+
+    @Test
+    void testFromThrowableStackTraceContent() {
+        Exception exception = new RuntimeException("Test message");
+        ErrorRequest errorRequest = LambdaErrorConverter.fromThrowable(exception);
+        
+        String[] stackTrace = errorRequest.stackTrace;
+        assertNotNull(stackTrace);
+        assertTrue(stackTrace.length > 0);
+        
+        boolean foundTestClass = false;
+        for (String traceLine : stackTrace) {
+            if (traceLine.contains(LambdaErrorConverterTest.class.getSimpleName())) {
+                foundTestClass = true;
+                break;
+            }
+        }
+        assertTrue(foundTestClass);
+    }
+}