diff --git a/testenv.docker b/testenv.docker
index f195d22..a94d242 100644
--- a/testenv.docker
+++ b/testenv.docker
@@ -1,7 +1,7 @@
 FROM eu.gcr.io/shad-ts/grader/go-build:latest
 
-RUN go install gitlab.com/slon/shad-go/tools/testtool
-
 COPY . /opt/shad
 
-RUN find /opt/shad/private -name '*.cpp' -or -name '*.h' | xargs chmod o-rwx
+RUN cd /opt/shad && go install gitlab.com/slon/shad-go/tools/testtool
+
+RUN find /opt/shad | xargs chmod o-rwx