switch to codecov for automatic combining of coverage reports

.coveragerc

@@ -8,4 +8,4 @@ omit=
 precision = 1
 exclude_lines =
   pragma: no cover
-  abc.abstractmethod
+  return NotImplemented

.travis.yml

@@ -12,44 +12,39 @@ matrix:
   include:
     # Each job performs a single task, and sets a "TASK" var so it's evident in the build matrix.
 
-    # One-off jobs. Override "script" to do something other than run the default (pytest).
+    # One-off jobs. Override "script" and "install" to do something other than run the default (pytest).
     - env: TASK=build-docs
-      before_script: travis_retry pip install -U Sphinx
+      install: travis_retry pip install Sphinx
       script: travis_retry ./build-docs.sh linkcheck
     - env: TASK=pylint
-      before_script: travis_retry pip install -U pylint
+      install: travis_retry pip install .[test] && travis_retry pip install pylint
       script: pylint bidict tests setup.py
     - env: TASK=flake8
-      before_script: travis_retry pip install -U flake8
+      install: travis_retry pip install flake8
       script: flake8 bidict tests/*.py
     - env: TASK=pydocstyle
-      before_script: travis_retry pip install -U pydocstyle
+      install: travis_retry pip install pydocstyle
       script: pydocstyle bidict
     - env: TASK=test-with-optimization-flag  # make sure there are no relied-on side effects in assert statements
+      install: echo "(no extra install needed for doctest)"
       script: python3 -O -m doctest -o IGNORE_EXCEPTION_DETAIL -o ELLIPSIS tests/*.txt
 
     # Run the test suite with all supported Python versions on Linux.
     # Only run these tests for master since they're so slow on Travis.
-    - env: TASK=pytest PYVER=2.7.14
+    # Enable coverage for the latest stable CPython 2 and 3 releases and PyPy on Linux.
+    - env: TASK=pytest PYVER=2.7.14 COVERAGE=1
       if: branch = master
     - env: TASK=pytest PYVER=3.4.7
       if: branch = master
     - env: TASK=pytest PYVER=3.5.3
       if: branch = master
-    # Enable coverage for the latest stable Python 3 release on Linux.
     - env: TASK=pytest PYVER=3.6.3 COVERAGE=1
       if: branch = master
-      before_script: travis_retry pip install -e .[coverage]
-      script:
-        - |
-            py.test --cov=bidict --cov-config=.coveragerc || exit 1
-            travis_retry pip install coveralls || exit 1
-            coveralls
     - env: TASK=pytest PYVER=3.7-dev
       if: branch = master
     - env: TASK=pytest PYVER=pypy2.7-5.9.0
       if: branch = master
-    - env: TASK=pytest PYVER=pypy3.5-5.9.0
+    - env: TASK=pytest PYVER=pypy3.5-5.9.0 COVERAGE=1
       if: branch = master
 
     # Run the test suite with all supported Python versions on macOS.
@@ -121,11 +116,23 @@ before_install:
       echo "VIRTUAL_ENV=$VIRTUAL_ENV"
 
 install:
-  - travis_retry pip install -e .[test]
+  - if [[ -n $COVERAGE ]]; then EXTRAS="test,coverage"; else EXTRAS="test"; fi
+  - travis_retry pip install .[$EXTRAS]
   - py.test --version
 
 script:
-  - py.test
+  - if [[ -n $COVERAGE ]]; then COVARGS="--cov=bidict --cov-config=.coveragerc"; fi
+  - py.test $COVARGS
+
+after_success:
+  - |
+      if [[ -f .coverage ]]; then
+        echo "Installing codecov..."
+        travis_retry pip install codecov || exit 1
+        echo
+        echo "Uploading coverage report..."
+        codecov || exit 1
+      fi
 
 before_cache:
   - rm -rf $HOME/.cache/pip/log

README.rst

@@ -32,8 +32,8 @@ Status
     :target: https://ci.appveyor.com/project/jab/bidict
     :alt: AppVeyor build status (Windows)
 
-.. image:: https://coveralls.io/repos/jab/bidict/badge.svg?branch=master
-    :target: https://coveralls.io/github/jab/bidict
+.. image:: https://codecov.io/gh/jab/bidict/branch/master/graph/badge.svg
+    :target: https://codecov.io/gh/jab/bidict
     :alt: Test coverage
 
 .. image:: https://api.codacy.com/project/badge/Grade/6628756a73254cd895656348236833b8
@@ -66,7 +66,7 @@ Bidict:
 - has carefully designed APIs for
   safety, simplicity, flexibility, and ergonomics,
 - is CPython-, PyPy-, Python 2-, and Python 3-compatible,
-- has extensive `test coverage <https://coveralls.io/github/jab/bidict>`_,
+- has extensive `test coverage <https://codecov.io/gh/jab/bidict>`_,
   including property-based tests and benchmarks,
   which are run continuously on all supported Python versions and OSes,
 - integrates with Python’s collections interfaces and abstract base classes,