Add possibility to run tests for runexec with sudo

with a different user account.

.travis.yml

@@ -13,10 +13,10 @@ install:
   - if [ "$TRAVIS_PYTHON_VERSION" == "3.2" ]; then travis_retry pip install coverage==3.7.1; else travis_retry pip install coverage; fi
   - travis_retry pip install -e git+https://github.com/codacy/python-codacy-coverage.git#egg=codacy
 before_script:
-  - sudo ./.travis-setup.sh "$USER" benchmarks
+  - sudo ./.travis-setup.sh "$USER" "$BENCHEXEC_TEST_USER"
   - printf 'import coverage\ncoverage.process_startup()\n' > "/home/travis/virtualenv/python${TRAVIS_PYTHON_VERSION}/lib/python${TRAVIS_PYTHON_VERSION}/sitecustomize.py"
 env:
-  - COVERAGE_PROCESS_START=.coveragerc
+  - BENCHEXEC_TEST_USER=benchmarks COVERAGE_PROCESS_START=.coveragerc
 script:
   - coverage run setup.py test
 after_success:

benchexec/test_runexecutor.py

@@ -393,8 +393,10 @@ class TestRunExecutorWithSudo(TestRunExecutor):
     would not be good, either.
     """
 
-    # sudo allows refering to numerical uids with '#'
-    user = '#' + str(os.getuid())
+    # Use user name defined in environment variable if present,
+    # or fall back to current user (sudo always allows this).
+    # sudo allows refering to numerical uids with '#'.
+    user = os.environ.get('BENCHEXEC_TEST_USER', '#' + str(os.getuid()))
 
     def setUp(self):
         try: