Test docs only with Python 3.5

Author: Alexander-N

.travis.yml

@@ -13,7 +13,7 @@ matrix:
       env: FEATURES=python2
     - name: Python 3.5
       python: "3.5"
-      env: FEATURES=python3
+      env: FEATURES="python3 test-doc"
     - name: Python 3.6
       python: "3.6"
       env: FEATURES=python3

ci/travis/test.sh

@@ -2,7 +2,7 @@
 set -ex
 
 cargo clean
-cargo test --features "$FEATURES num-complex test-doc"
+cargo test --features "$FEATURES num-complex"
 if [ $TRAVIS_JOB_NAME = 'Minimum nightly' ]; then
     cargo fmt --all -- --check
     cargo clippy --features "$FEATURES num-complex"