diff --git a/.travis.sh b/.travis.sh
index 05d39eb1389d0891095e90b5c46d8e16c77d8e38..d49b6acfb4943808b4b21f5d61ca034bf95b2474 100755
--- a/.travis.sh
+++ b/.travis.sh
@@ -51,10 +51,9 @@ docker build -t $TRAVIS_REPO_SLUG .
 # Prepare build regression test
 pushd /tmp
 mkdocs new test && cd test
-echo "theme: \n  name: material" >> mkdocs.yml
 
 # Test Docker image build
-docker run --rm -it -v `pwd`:/docs $TRAVIS_REPO_SLUG build
+docker run --rm -it -v `pwd`:/docs $TRAVIS_REPO_SLUG build --theme material
 
 # Return to original directory
 popd
diff --git a/Dockerfile b/Dockerfile
index 8f065d466eb6a0792ee6c6d708a5ae928e10774c..ab0af453390923ac253187740a05f2dbf2a37904 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -33,7 +33,7 @@ COPY setup.py setup.py
 
 # Perform build and cleanup artifacts
 RUN \
-  apk add -U openssh git && \
+  apk add --no-cache openssh git && \
   python setup.py install 2>/dev/null && \
   rm -rf /tmp/*