diff --git a/lib/__tests__/index.test.js b/lib/__tests__/index.test.js
index d213b0f..e1920f9 100644
--- a/lib/__tests__/index.test.js
+++ b/lib/__tests__/index.test.js
@@ -283,7 +283,7 @@ describe( 'lib/index', function() {
 
                 expect( tester._event ).to.eql( {} );
 
-                let returnValue = tester.event( { one: 1 } );
+                let returnValue = tester.event( { one: 1, dummy: undefined } );
 
                 expect( returnValue ).to.equal( tester );
                 expect( tester._event ).to.eql( { one: 1 } );
@@ -309,8 +309,8 @@ describe( 'lib/index', function() {
                 tester.event( [ e1, e2 ] );
 
                 expect( tester._event ).to.be.an( 'Array' );
-                expect( tester._event[0] ).to.equal( e1 );
-                expect( tester._event[1] ).to.equal( e2 );
+                expect( tester._event[0] ).to.eql( e1 );
+                expect( tester._event[1] ).to.eql( e2 );
             });
 
             it( 'event is a function', function() {
@@ -429,7 +429,7 @@ describe( 'lib/index', function() {
                 return tester.expectResult( ( result ) => {
 
                         // should be the original object
-                        expect( result ).to.equal( clientContext );
+                        expect( result ).to.eql( clientContext );
                     });
             });
 
@@ -456,7 +456,7 @@ describe( 'lib/index', function() {
                 return tester.expectResult( ( result ) => {
 
                         // should be the original object
-                        expect( result ).to.equal( clientContext );
+                        expect( result ).to.eql( clientContext );
                     });
             });
         });
@@ -1468,36 +1468,70 @@ describe( 'lib/index', function() {
 
                 await LambdaTester( (event, context) => {
 
-                        context.succeed( 'ok' );
+                        context.succeed( { ok: true, dummy: undefined } );
                     }).expectResult( (result) => {
 
-                        expect( result ).to.equal( 'ok' );
+                        expect( result ).to.eql( { ok: true } );
                     });
             });
 
+            it( 'without strict mode, contextSucceed with no value', async function() {
+
+                await LambdaTester( (event, context) => {
+
+                    context.succeed();
+                }).expectResult( (result) => {
+
+                    expect( result ).to.equal( null );
+                });
+            });
+
             it( 'without strict mode, callback', async function() {
 
                 await LambdaTester( (event, context, callback) => {
 
-                        callback( null, 'ok' );
+                        callback( null, { ok: true, dummy: undefined } );
                     }).expectResult( (result) => {
 
-                        expect( result ).to.equal( 'ok' );
+                        expect( result ).to.eql( { ok: true } );
                     });
             });
 
+            it( 'without strict mode, callback with no value', async function() {
+
+                await LambdaTester( (event, context, callback) => {
+
+                    callback( null );
+                }).expectResult( (result) => {
+
+                    expect( result ).to.equal( null );
+                });
+            });
+
             it( 'without strict mode, promise', async function() {
 
                 await LambdaTester( () => {
 
-                        return Promise.resolve( 'ok' );
+                        return Promise.resolve( { ok: true, dummy: undefined } );
 
                     }).expectResult( (result) => {
 
-                        expect( result ).to.equal( 'ok' );
+                        expect( result ).to.eql( { ok: true } );
                     });
             });
 
+            it( 'without strict mode, promise with no value', async function() {
+
+                await LambdaTester( () => {
+
+                    return Promise.resolve();
+
+                }).expectResult( (result) => {
+
+                    expect( result ).to.equal( null );
+                });
+            });
+
             it( 'without verifier', function() {
 
                 return LambdaTester( LAMBDA_SIMPLE_CALLBACK )
diff --git a/lib/index.js b/lib/index.js
index c5880b4..8425897 100644
--- a/lib/index.js
+++ b/lib/index.js
@@ -148,14 +148,7 @@ class LambdaTester {
             evt = evt( lambdaEventMock );
         }
 
-        if( isObject( evt ) && !Array.isArray( evt )) {
-
-            this._event = { ...evt };
-        }
-        else {
-
-            this._event = evt;
-        }
+        this._event = JSON.parse( JSON.stringify( evt ) )
 
         return this;
     }
diff --git a/lib/runner.js b/lib/runner.js
index e26061c..9a6b48e 100644
--- a/lib/runner.js
+++ b/lib/runner.js
@@ -122,6 +122,11 @@ async function runVerifier( verifier, result, additional ) {
     }
 }
 
+// This function simulates the serialization process between the client and the lambda service.
+function convertResult( result ) {
+    return result === undefined ? null : JSON.parse( JSON.stringify( result ) );
+}
+
 class LambdaRunner {
 
     constructor( expectedState, verifier, options = {} ) {
@@ -164,14 +169,14 @@ class LambdaRunner {
 
                 let context = this._createContext( resolve, { startTime } );
 
-                let callback = ( err, result ) => resolve( { state: err ? States.callbackError : States.callbackResult, err, result } );
+                let callback = ( err, result ) => resolve( { state: err ? States.callbackError : States.callbackResult, err, result: convertResult( result ) } );
 
                 const ret = handler( this.event, context, callback );
 
                 if( isPromise( ret ) ) {
 
                     ret.then(
-                        (result) => resolve( { state: States.promiseResolve, err: null, result } ),
+                        (result) => resolve( { state: States.promiseResolve, err: null, result: convertResult( result ) } ),
                         (err) => resolve( { state: States.promiseReject, err, result: null } )
                     );
                 }
@@ -223,8 +228,8 @@ class LambdaRunner {
             ...this.context,
 
             fail: ( err ) => resolve( { state: States.contextFail, err } ),
-            succeed: ( result ) => resolve( { state: States.contextSucceed, result } ),
-            done: ( err, result ) => resolve( { state: err ? States.contextFail : States.contextSucceed, err, result } ),
+            succeed: ( result ) => resolve( { state: States.contextSucceed, result: convertResult(result) } ),
+            done: ( err, result ) => resolve( { state: err ? States.contextFail : States.contextSucceed, err, result: convertResult( result ) } ),
             getRemainingTimeInMillis: () => {
 
                     let remaining = this.timeout - (Date.now() - additional.startTime);