diff --git a/.travis.yml b/.travis.yml
index 8b56a08ac..b9f815d6a 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -9,7 +9,7 @@ before_install:
   - go get github.com/mattn/goveralls
 
 script:
-  - go test github.com/v2ray/v2ray-core/...
+  - go test -tags json github.com/v2ray/v2ray-core/...
   - ./testing/coverage/coverall
 
 env:
diff --git a/testing/coverage/coverall b/testing/coverage/coverall
index 2fd99f44d..c26ba8e43 100755
--- a/testing/coverage/coverall
+++ b/testing/coverage/coverall
@@ -6,7 +6,7 @@ function test_package {
   DIR="github.com/v2ray/v2ray-core/$1"
   DEP=$(go list -f '{{ join .Deps "\n" }}' $DIR | grep v2ray | tr '\n' ',')
   DEP=${DEP}$DIR
-  go test -coverprofile=coversingle.out -coverpkg=$DEP $DIR || FAIL=1
+  go test -tags json -coverprofile=coversingle.out -coverpkg=$DEP $DIR || FAIL=1
   if [ -f coversingle.out ]; then
     cat coversingle.out | grep -v "mode: set" >> coverall.out
     rm coversingle.out