Use absolute locations for sources

.travis.yml

@@ -58,13 +58,15 @@ env:
 install: .travis/install.sh functional-tests docs
 script:
 - export PYTHONPATH="${TRAVIS_BUILD_DIR}/.travis"
-# As we fork processes, we need to make sure to point where each forked process
-# will put its .coverage... files. Otherwise they may be created under directories
-# that `coverage combine` isn't expecting, causing the report to omit tests.
-# On the other hand, changing .coveragerc directly affects developers running
-# coverage locally. Therefore, we have this sed line here only for Travis.
-- sed -i -e "s|data_file=.coverage|data_file=${TRAVIS_BUILD_DIR}/.coverage|g" .coveragerc
-- coverage run .travis/cover.py
+# When we run cylc commands, there are processes being forked, that get a
+# new working directory. As .coveragerc contains relatives paths, it fails
+# to produce the correct coverage, unless we use absolute paths. The `sed`
+# call below tries to define the data_file, and sources locations for Travis.
+- sed -e "s|data_file=.coverage|data_file=${TRAVIS_BUILD_DIR}/.coverage|g; s|./bin|${TRAVIS_BUILD_DIR}/bin|g; s|./lib|${TRAVIS_BUILD_DIR}/lib|g" .coveragerc > /tmp/.coveragerc
+# And some tests fail if we touch files in the git working directory, due
+# to Cylc's version appearing with the "dirty" suffix. To avoid this, we
+# are using a new coveragerc created under the temporary directory.
+- coverage run --rcfile /tmp/.coveragerc .travis/cover.py
 - unset PYTHONPATH
 after_script: .travis/after_script.sh
 after_success: