enh: run tests in parallel

Author: mgxd

.codecov.yml

@@ -1,5 +1,5 @@
 coverage:
   range: "0...100"
   ignore:
-    - "nitransforms/tests/data"
+    - "**/data"
     - "setup.py"

.travis.yml

@@ -9,7 +9,7 @@ install:
   - pip install -U -e .[test]
 
 script:
-  - pytest -v --cov nitransforms --cov-config .coveragerc --cov-report xml:cov.xml --doctest-modules nitransforms
+  - pytest -v -n auto --cov nitransforms --cov-config .coveragerc --cov-report xml:cov.xml --doctest-modules nitransforms
 
 after_success:
   - codecov --file cov.xml --flags unittests -e TRAVIS_JOB_NUMBER

setup.cfg

@@ -12,6 +12,7 @@ install_requires =
 test_requires =
     pytest
     pytest-cov
+    pytest-xdist
     nose
     codecov
 packages = find:
@@ -21,6 +22,7 @@ include_package_data = True
 test =
     pytest
     pytest-cov
+    pytest-xdist
     nose
     codecov
 tests =