func TestRenderInvokeEmptyHeaders(t *testing.T) {
	flowTest := testdata.NewFlowTest()
	flowTest.ConfigureForInit()
	handler := NewInvocationNextHandler(flowTest.RegistrationService, flowTest.RenderingService)
	responseRecorder := httptest.NewRecorder()
	appCtx := flowTest.AppCtx
	flowTest.ConfigureForInvoke(context.Background(), &interop.Invoke{})
	request := appctx.RequestWithAppCtx(httptest.NewRequest("", "/", nil), appCtx)
	handler.ServeHTTP(responseRecorder, request)
	headers := responseRecorder.Header()
	assert.Equal(t, "application/json", headers.Get("Content-Type"))
	assert.Len(t, headers, 1)
	assert.Equal(t, http.StatusOK, responseRecorder.Code)
}
TestRenderInvokeEmptyHeaders tests that headers
are not rendered when not set.
package handler
import (
	"context"
	"errors"
	"fmt"
	"log"
	"math"
	"net/http"
	"net/http/httptest"
	"os"
	"runtime"
	"strconv"
	"strings"
	"testing"
	"time"
	"github.com/stretchr/testify/assert"
	"go.amzn.com/lambda/appctx"
	"go.amzn.com/lambda/interop"
	"go.amzn.com/lambda/metering"
	"go.amzn.com/lambda/telemetry"
	"go.amzn.com/lambda/testdata"
)