fix travis build

.travis.yml

@@ -1,43 +1,31 @@
 sudo: false
 language: python
-matrix:
-  fast_finish: true
-  include:
-  - python: 2.7
-    env: TEST_TARGET=default
-  - python: 3.5
-    env: TEST_TARGET=default
-  - python: 3.6
-    env: TEST_TARGET=default
-  - python: 3.6
-    env: TEST_TARGET=coding_standards
-  - python: 3.7
-    env: TEST_TARGET=default
-  - python: 3.7
-    env: TEST_TARGET=coding_standards
-  - python: 3.8
-    env: TEST_TARGET=default
-  - python: 3.8
-    env: TEST_TARGET=coding_standards
-before_install:
-- wget http://bit.ly/miniconda -O miniconda.sh
-- bash miniconda.sh -b -p $HOME/miniconda
-- export PATH="$HOME/miniconda/bin:$PATH"
-- conda config --set always_yes yes --set changeps1 no --set show_channel_urls true
-- conda update conda
-- conda config --add channels conda-forge --force
-- conda create --name TEST python=$TRAVIS_PYTHON_VERSION --file requirements.txt --file
-  requirements-dev.txt
-- source activate TEST
-- pip install check-manifest
-- export DISPLAY=:99.0
-- sh -e /etc/init.d/xvfb start
+python: 
+  - "2.7"
+  - "3.5"
+  - "3.6"
+  - "3.7"
+  - "3.8"
+env:
+  - TEST_TARGET=default
+  - TEST_TARGET=coding_standards
+jobs:
+  exclude:
+    - python: "2.7"
+      env: TEST_TARGET=coding_standards
+    - python: "3.5"
+      env: TEST_TARGET=coding_standards
+
+# command to install dependencies
 install:
-- python setup.py install
+  - pip install -r requirements.txt
+  - pip install -r requirements-dev.txt
+  - python setup.py install
 script:
-- if [[ $TEST_TARGET == 'default' ]]; then pytest --verbose tests ; fi
-- if [[ $TEST_TARGET == 'coding_standards' ]]; then flake8 --ignore=E501 windrose
-  samples tests ; fi
+  - if [[ $TEST_TARGET == 'default' ]]; then pytest --verbose tests ; fi
+  - if [[ $TEST_TARGET == 'coding_standards' ]]; then flake8 --ignore=E501 windrose samples ; fi
+  - if [[ $TEST_TARGET == 'coding_standards' ]]; then flake8 --ignore=E501,E402 tests ; fi
+
 deploy:
   provider: pypi
   user: "scls"