Add conda and torchvision to .travis.yml

Author: juneoh

.travis.yml

@@ -8,6 +8,19 @@ python:
   - "3.5"
   - "3.6"
 # command to install dependencies
-install: "pip install -r requirements.txt"
+install:
+  # Install conda.
+  - if [[ "$TRAVIS_PYTHON_VERSION" == "2.7" ]]; then
+      wget https://repo.continuum.io/miniconda/Miniconda2-latest-Linux-x86_64.sh -O miniconda.sh;
+    else
+      wget https://repo.continuum.io/miniconda/Miniconda3-latest-Linux-x86_64.sh -O miniconda.sh;
+    fi
+  - bash miniconda.sh -b -p $HOME/miniconda
+  - export OPATH="$PATH" && export PATH="$HOME/miniconda/bin:$PATH"
+  - conda create -q -y -n test-environment python=$TRAVIS_PYTHON_VERSION pytest
+  - source activate test-environment
+  # Attempt to install torchvision; on failure, revert back to pre-conda environment.
+  - conda install -q -y torchvision -c soumith || export PATH="$OPATH"
+  - pip install -r requirements.txt
 # command to run tests
-script: py.test -v
+script: py.test -v