diff --git a/tests/test_sync.py b/tests/test_sync.py
index ae53e109..5afb53a1 100644
--- a/tests/test_sync.py
+++ b/tests/test_sync.py
@@ -46,10 +46,6 @@ def tarball_name(spec):
 TAR_NAMES = tarball_name(GOOD_SPEC), tarball_name(BAD_SPEC), tarball_name(MISSING_SPEC)
 
 
-def dist_dir(spec):
-    return "/sw/dist/{package}/{package}-{version}-{revision}".format(**spec)
-
-
 class MockRequest:
     def __init__(self, j, simulate_err=False):
         self.j = j
diff --git a/tox.ini b/tox.ini
index f1f2addc..f8a5dc10 100644
--- a/tox.ini
+++ b/tox.ini
@@ -61,43 +61,56 @@ changedir = {envtmpdir}
 commands =
     # The first coverage command shouldn't have an -a, so we completely replace
     # the coverage info from the last run.
-    coverage run {envbindir}/aliBuild analytics off
+    coverage run --source={toxinidir} {toxinidir}/aliBuild analytics off
     test -e .config/alibuild/disable-analytics
     test ! -e .config/alibuild/analytics-uuid
-    coverage run -a {envbindir}/aliBuild analytics on
+    coverage run --source={toxinidir} -a {toxinidir}/aliBuild analytics on
     test ! -e .config/alibuild/disable-analytics
     test -e .config/alibuild/analytics-uuid
-    coverage run -a {envbindir}/aliBuild analytics off
+    coverage run --source={toxinidir} -a {toxinidir}/aliBuild analytics off
     test -e .config/alibuild/disable-analytics
     test -e .config/alibuild/analytics-uuid
 
-    coverage run -a {envbindir}/aliBuild version
+    coverage run --source={toxinidir} -a {toxinidir}/aliBuild version
 
-    coverage run -a -m unittest discover {toxinidir}/tests
+    coverage run --source={toxinidir} -a -m unittest discover {toxinidir}/tests
 
     git clone -b O2-v1.3.0 --depth 1 https://github.com/alisw/alidist
 
-    coverage run -a {envbindir}/aliBuild -a slc7_x86-64 -z test-init init zlib
+    coverage run --source={toxinidir} -a {toxinidir}/aliBuild -a slc7_x86-64 -z test-init init zlib
     # This command is expected to fail, but run it for the coverage anyway.
     # A leading "-" means tox ignores the exit code.
-    - coverage run -a {envbindir}/aliBuild build non-existing -a slc7_x86-64 --no-system --disable GCC-Toolchain
+    - coverage run --source={toxinidir} -a {toxinidir}/aliBuild build non-existing -a slc7_x86-64 --no-system --disable GCC-Toolchain
 
     # TODO: do we need these? This seems to be at least partially covered by
     # unit tests in tests/tests_parseRecipe.py.
-    sh -c 'coverage run -a {envbindir}/aliBuild -c {toxinidir}/tests/testdist build broken1 --force-unknown-architecture --no-system --disable GCC-Toolchain 2>&1 | tee /dev/stderr | grep "Header missing"'
-    sh -c 'coverage run -a {envbindir}/aliBuild -c {toxinidir}/tests/testdist build broken2 --force-unknown-architecture --no-system --disable GCC-Toolchain 2>&1 | tee /dev/stderr | grep "Empty recipe"'
-    sh -c 'coverage run -a {envbindir}/aliBuild -c {toxinidir}/tests/testdist build broken3 --force-unknown-architecture --no-system --disable GCC-Toolchain 2>&1 | tee /dev/stderr | grep "Unable to parse"'
-    sh -c 'coverage run -a {envbindir}/aliBuild -c {toxinidir}/tests/testdist build broken4 --force-unknown-architecture --no-system --disable GCC-Toolchain 2>&1 | tee /dev/stderr | grep "Malformed header"'
-    sh -c 'coverage run -a {envbindir}/aliBuild -c {toxinidir}/tests/testdist build broken5 --force-unknown-architecture --no-system --disable GCC-Toolchain 2>&1 | tee /dev/stderr | grep "Missing package"'
-    sh -c 'coverage run -a {envbindir}/aliBuild -c {toxinidir}/tests/testdist build broken6 --force-unknown-architecture --no-system --disable GCC-Toolchain 2>&1 | tee /dev/stderr | grep "while scanning a quoted scalar"'
-    sh -c 'coverage run -a {envbindir}/aliBuild -c {toxinidir}/tests/testdist build broken7 --force-unknown-architecture --no-system --disable GCC-Toolchain 2>&1 | tee /dev/stderr | grep "Malformed entry prefer_system"'
+    sh -c 'coverage run --source={toxinidir} -a {toxinidir}/aliBuild -c {toxinidir}/tests/testdist build broken1 --force-unknown-architecture --no-system --disable GCC-Toolchain 2>&1 | tee /dev/stderr | grep "Header missing"'
+    sh -c 'coverage run --source={toxinidir} -a {toxinidir}/aliBuild -c {toxinidir}/tests/testdist build broken2 --force-unknown-architecture --no-system --disable GCC-Toolchain 2>&1 | tee /dev/stderr | grep "Empty recipe"'
+    sh -c 'coverage run --source={toxinidir} -a {toxinidir}/aliBuild -c {toxinidir}/tests/testdist build broken3 --force-unknown-architecture --no-system --disable GCC-Toolchain 2>&1 | tee /dev/stderr | grep "Unable to parse"'
+    sh -c 'coverage run --source={toxinidir} -a {toxinidir}/aliBuild -c {toxinidir}/tests/testdist build broken4 --force-unknown-architecture --no-system --disable GCC-Toolchain 2>&1 | tee /dev/stderr | grep "Malformed header"'
+    sh -c 'coverage run --source={toxinidir} -a {toxinidir}/aliBuild -c {toxinidir}/tests/testdist build broken5 --force-unknown-architecture --no-system --disable GCC-Toolchain 2>&1 | tee /dev/stderr | grep "Missing package"'
+    sh -c 'coverage run --source={toxinidir} -a {toxinidir}/aliBuild -c {toxinidir}/tests/testdist build broken6 --force-unknown-architecture --no-system --disable GCC-Toolchain 2>&1 | tee /dev/stderr | grep "while scanning a quoted scalar"'
+    sh -c 'coverage run --source={toxinidir} -a {toxinidir}/aliBuild -c {toxinidir}/tests/testdist build broken7 --force-unknown-architecture --no-system --disable GCC-Toolchain 2>&1 | tee /dev/stderr | grep "Malformed entry prefer_system"'
 
-    coverage run -a {envbindir}/aliBuild build zlib -a slc7_x86-64 --no-system --disable GCC-Toolchain
+    coverage run --source={toxinidir} -a {toxinidir}/aliBuild build zlib -a slc7_x86-64 --no-system --disable GCC-Toolchain
     alienv -a slc7_x86-64 q
     alienv -a slc7_x86-64 setenv zlib/latest -c bash -c '[[ $LD_LIBRARY_PATH == */zlib/* ]]'
-    coverage run -a {envbindir}/aliBuild -a slc7_x86-64 doctor AliPhysics
-    coverage run -a {envbindir}/aliBuild -a slc7_x86-64 build zlib --dry-run
-    coverage run -a {envbindir}/aliBuild --aggressive-cleanup --docker -a slc7_x86-64 --always-prefer-system -d build zlib
+    coverage run --source={toxinidir} -a {toxinidir}/aliBuild -a slc7_x86-64 doctor AliPhysics
+    coverage run --source={toxinidir} -a {toxinidir}/aliBuild -a slc7_x86-64 build zlib --dry-run
+    coverage run --source={toxinidir} -a {toxinidir}/aliBuild --aggressive-cleanup --docker -a slc7_x86-64 --always-prefer-system -d build zlib
     # Test for devel packages
-    coverage run -a {envbindir}/aliBuild init zlib
-    coverage run -a {envbindir}/aliBuild --aggressive-cleanup --docker -a slc7_x86-64 --always-prefer-system -d build zlib
+    coverage run --source={toxinidir} -a {toxinidir}/aliBuild init zlib
+    coverage run --source={toxinidir} -a {toxinidir}/aliBuild --aggressive-cleanup --docker -a slc7_x86-64 --always-prefer-system -d build zlib
+
+[coverage:run]
+branch = True
+omit =
+    */.tox/*/lib/*
+
+[coverage:report]
+exclude_lines =
+    # Don't complain if tests don't hit defensive assertion code:
+    raise AssertionError
+    raise NotImplementedError
+    # Don't complain if non-runnable code isn't run:
+    if __name__ == .__main__.: