setup.cfg: Fix xdg env vars to not affect the hostbschubert/fix-xdg-temppaths

A fix was made in
https://gitlab.com/BuildStream/buildstream/merge_requests/1244
in order to set xdg_* env variables inside of the test's directory
to avoid importing data from the host.

There was however still two problems:
- When a variable was not set, it was set with a relative path, which
would create a configuration for BuildStream that is invalid.
- When a variable was set and running with pytest directly, we would
still use the variable's value, which would be the host one.

This ensure this can never happen, by not relying on the same variable's
name and always overriding them.

3 files changed, 23 insertions, 8 deletions

diff --git a/setup.cfg b/setup.cfg
index 7a62f9282..a8919fdca 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -16,10 +16,7 @@ norecursedirs = tests/integration/project integration-cache tmp __pycache__ .egg
 python_files = tests/*/*.py
 env =
     D:BST_TEST_SUITE=True
-    D:HOME=./tmp
-    D:XDG_CACHE_HOME=./tmp/cache
-    D:XDG_CONFIG_HOME=./tmp/config
-    D:XDG_DATA_HOME=./tmp/share
+
 markers =
     integration: run test only if --integration option is specified
     remoteexecution: run test only if --remote-execution option is specified
diff --git a/tests/conftest.py b/tests/conftest.py
index 9189d263e..68fdba7fb 100755
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -137,3 +137,21 @@ register_repo_kind('zip', Zip, None)
 # buildstream.testing
 def pytest_sessionstart(session):
     sourcetests_collection_hook(session)
+
+
+#################################################
+#             Isolated environment              #
+#################################################
+@pytest.fixture(scope="session", autouse=True)
+def set_xdg_paths(pytestconfig):
+    for env_var, default in [
+            ("HOME", "tmp"),
+            ("XDG_CACHE_HOME", "tmp/cache"),
+            ("XDG_CONFIG_HOME", "tmp/config"),
+            ("XDG_DATA_HOME", "tmp/share"),
+    ]:
+        value = os.environ.get("BST_TEST_{}".format(env_var))
+        if value is None:
+            value = os.path.join(pytestconfig.getoption("basetemp"), default)
+
+        os.environ[env_var] = value
diff --git a/tox.ini b/tox.ini
index 50699177e..a00197d13 100644
--- a/tox.ini
+++ b/tox.ini
@@ -55,10 +55,10 @@ passenv =
 #
 setenv =
     py{35,36,37}: COVERAGE_FILE = {envtmpdir}/.coverage
-    py{35,36,37}: HOME = {envtmpdir}
-    py{35,36,37}: XDG_CACHE_HOME = {envtmpdir}/cache
-    py{35,36,37}: XDG_CONFIG_HOME = {envtmpdir}/config
-    py{35,36,37}: XDG_DATA_HOME = {envtmpdir}/share
+    py{35,36,37}: BST_TEST_HOME = {envtmpdir}
+    py{35,36,37}: BST_TEST_XDG_CACHE_HOME = {envtmpdir}/cache
+    py{35,36,37}: BST_TEST_XDG_CONFIG_HOME = {envtmpdir}/config
+    py{35,36,37}: BST_TEST_XDG_DATA_HOME = {envtmpdir}/share
     # This is required to get coverage for Cython
     py{35,36,37}-!nocover: BST_CYTHON_TRACE = 1