update tests

- fix failing test cases
- add comment about motivation for change in index.js

__tests__/index.js

@@ -51,6 +51,8 @@ function mapApiGatewayEventToHttpRequest(headers) {
         headers
     }
     const eventClone = JSON.parse(JSON.stringify(event))
+    // NOTE: mapApiGatewayEventToHttpRequest will specify Content-Length if not specified
+    eventClone.headers = Object.assign(eventClone.headers, {'Content-Length': Buffer.byteLength(eventClone.body)})
     delete eventClone.body
     const context = {
         'foo': 'bar'
@@ -68,6 +70,7 @@ test('mapApiGatewayEventToHttpRequest: with headers', () => {
         method: 'GET',
         path: '/foo',
         headers: {
+            'Content-Length': Buffer.byteLength('Hello serverless!'),
             'x-foo': 'foo',
             'x-apigateway-event': encodeURIComponent(JSON.stringify(r.eventClone)),
             'x-apigateway-context': encodeURIComponent(JSON.stringify(r.context))
@@ -83,6 +86,7 @@ test('mapApiGatewayEventToHttpRequest: without headers', () => {
         method: 'GET',
         path: '/foo',
         headers: {
+            'Content-Length': Buffer.byteLength('Hello serverless!'),
             'x-apigateway-event': encodeURIComponent(JSON.stringify(r.eventClone)),
             'x-apigateway-context': encodeURIComponent(JSON.stringify(r.context))
         },

index.js

@@ -35,7 +35,8 @@ function mapApiGatewayEventToHttpRequest(event, context, socketPath) {
     const headers = event.headers || {} // NOTE: Mutating event.headers; prefer deep clone of event.headers
     const eventWithoutBody = Object.assign({}, event)
     delete eventWithoutBody.body
-
+
+    // NOTE: API Gateway is not setting Content-Length header on any requests even when they have a body  
     if (event.body && !headers['Content-Length']) {
       headers['Content-Length'] = Buffer.byteLength(event.body)
     }