use docker exec instead of mounting to work around a travis issue

integrationtests/chrome_test.go

@@ -4,8 +4,6 @@ import (
 	"fmt"
 	"io"
 	"net/http"
-	"os"
-	"path/filepath"
 
 	"github.com/tebeka/selenium"
 
@@ -120,23 +118,11 @@ var _ = Describe("Chrome tests", func() {
 				close(done)
 			}, 10)
 
-			It("downloads a small file", func(done Done) {
-				var err error
-				err = wd.Get("https://quic.clemente.io/data")
+			It("downloads a small file", func() {
+				err := wd.Get("https://quic.clemente.io/data")
 				Expect(err).NotTo(HaveOccurred())
-				var file *os.File
-				Eventually(func() error {
-					file, err = os.Open(filepath.Join(downloadDir, "data"))
-					return err
-				}, 30, 0.1).ShouldNot(HaveOccurred())
-				fi, err := file.Stat()
-				Expect(err).ToNot(HaveOccurred())
-				Eventually(fi.Size(), 10, 0.1).Should(Equal(int64(dataLen)))
-				contents := make([]byte, dataLen)
-				_, err = file.Read(contents)
-				Expect(err).ToNot(HaveOccurred())
-				Expect(contents).To(Equal(data))
-				close(done)
+				Eventually(func() int { return getDownloadSize("data") }, 30, 0.1).Should(Equal(dataLen))
+				Expect(getDownloadMD5("data")).To(Equal(dataMD5))
 			}, 60)
 		})
 	}