.travis/*.sh: use homebrew python3 instead of compiling python3 from source with pyenv

This should speed it up a bit, as brew will download a pre-compiled "bottle", whereas pyenv compiles python from source.

The current 'python3' formula on homebrew is 3.6.0, so let's use that.

.travis.yml

@@ -22,7 +22,7 @@ matrix:
       env: TOXENV=py27-cov
     - language: generic
       os: osx
-      env: TOXENV=py35-cov
+      env: TOXENV=py36-cov
 
 install:
   - ./.travis/install.sh

.travis/after_success.sh

@@ -3,5 +3,9 @@
 set -e
 set -x
 
+if [ "$TRAVIS_OS_NAME" == "osx" ]; then
+    source .venv/bin/activate
+fi
+
 # upload coverage data to Codecov.io
-[[ ${TOXENV} == *"-cov"* ]] && python -m tox -e codecov
+[[ ${TOXENV} == *"-cov"* ]] && tox -e codecov

.travis/install.sh

@@ -3,34 +3,31 @@
 set -e
 set -x
 
-pip_options="--upgrade"
 ci_requirements="pip setuptools tox"
 
-if [[ "$(uname -s)" == 'Darwin' ]]; then
-    # install pyenv from the git repo (quicker than using brew)
-    git clone https://github.com/yyuu/pyenv.git ~/.pyenv
-    PYENV_ROOT="$HOME/.pyenv"
-    PATH="$PYENV_ROOT/bin:$PATH"
-    eval "$(pyenv init -)"
-
-    case "${TOXENV}" in
-        py27)
-            # install pip on the system python
-            curl -O https://bootstrap.pypa.io/get-pip.py
-            python get-pip.py --user
-            ;;
-        py35)
-            pyenv install 3.5.2
-            pyenv global 3.5.2
-            ;;
-    esac
-    pyenv rehash
-
-    # add --user option so we don't require sudo
-    pip_options="$pip_options --user"
-else
-    # on Linux, we're already in a virtualenv; no --user required
-    :
+if [ "$TRAVIS_OS_NAME" == "osx" ]; then
+    if [[ ${TOXENV} == *"py27"* ]]; then
+        # install pip on the system python
+        curl -O https://bootstrap.pypa.io/get-pip.py
+        python get-pip.py --user
+        # install virtualenv and create virtual environment
+        python -m pip install --user virtualenv
+        python -m virtualenv .venv/
+    elif [[ ${TOXENV} == *"py3"* ]]; then
+        # install/upgrade current python3 with homebrew
+        if brew list --versions python3 > /dev/null; then
+            brew upgrade python3
+        else
+            brew install python3
+        fi
+        # create virtual environment
+        python3 -m venv .venv/
+    else
+        echo "unsupported $TOXENV: "${TOXENV}
+        exit 1
+    fi
+    # activate virtual environment
+    source .venv/bin/activate
 fi
 
-python -m pip install $pip_options $ci_requirements
+python -m pip install $ci_requirements

.travis/run.sh

@@ -3,12 +3,8 @@
 set -e
 set -x
 
-if [[ "$(uname -s)" == "Darwin" ]]; then
-    PYENV_ROOT="$HOME/.pyenv"
-    PATH="$PYENV_ROOT/bin:$PATH"
-    eval "$(pyenv init -)"
+if [ "$TRAVIS_OS_NAME" == "osx" ]; then
+    source .venv/bin/activate
 fi
 
-# tox script may not be in the $PATH if we installed as --user
-# so we run it as module
-python -m tox
+tox