diff --git a/taskcluster/ci/test/raptor.yml b/taskcluster/ci/test/raptor.yml
index 4a0607a5fbb3..629cde615a3a 100644
--- a/taskcluster/ci/test/raptor.yml
+++ b/taskcluster/ci/test/raptor.yml
@@ -1,6 +1,7 @@
 job-defaults:
     max-run-time: 1800
     suite: raptor
+    workdir: /home/cltbld
     tier:
         by-test-platform:
             windows10-64-ccov/.*: 3
diff --git a/taskcluster/taskgraph/transforms/job/mozharness_test.py b/taskcluster/taskgraph/transforms/job/mozharness_test.py
index 28b9f1521e1d..37d74b856f70 100644
--- a/taskcluster/taskgraph/transforms/job/mozharness_test.py
+++ b/taskcluster/taskgraph/transforms/job/mozharness_test.py
@@ -337,7 +337,8 @@ def mozharness_test_on_native_engine(config, job, taskdesc):
     if test['max-run-time']:
         worker['max-run-time'] = test['max-run-time']
 
-    worker['env'] = env = {
+    env = worker.setdefault('env', {})
+    env.update({
         'GECKO_HEAD_REPOSITORY': config.params['head_repository'],
         'GECKO_HEAD_REV': config.params['head_rev'],
         'MOZHARNESS_CONFIG': ' '.join(mozharness['config']),
@@ -351,7 +352,7 @@ def mozharness_test_on_native_engine(config, job, taskdesc):
         "MOZ_HIDE_RESULTS_TABLE": '1',
         "MOZ_NODE_PATH": "/usr/local/bin/node",
         'MOZ_AUTOMATION': '1',
-    }
+    })
     # talos tests don't need Xvfb
     if is_talos:
         env['NEED_XVFB'] = 'false'
diff --git a/taskcluster/taskgraph/transforms/tests.py b/taskcluster/taskgraph/transforms/tests.py
index 21ede56f39fc..544a67bd012d 100644
--- a/taskcluster/taskgraph/transforms/tests.py
+++ b/taskcluster/taskgraph/transforms/tests.py
@@ -146,6 +146,9 @@ test_description_schema = Schema({
         'test-platform',
         basestring),
 
+    # base work directory used to set up the task.
+    Optional('workdir'): basestring,
+
     # the name by which this test suite is addressed in try syntax; defaults to
     # the test-name.  This will translate to the `unittest_try_name` or
     # `talos_try_name` attribute.
@@ -1097,6 +1100,9 @@ def make_job_description(config, tests):
         run['using'] = 'mozharness-test'
         run['test'] = test
 
+        if 'workdir' in test:
+            run['workdir'] = test.pop('workdir')
+
         jobdesc['worker-type'] = test.pop('worker-type')
         if test.get('fetches'):
             jobdesc['fetches'] = test.pop('fetches')
diff --git a/testing/mozharness/mozharness/mozilla/testing/raptor.py b/testing/mozharness/mozharness/mozilla/testing/raptor.py
index 0cec719c8765..09b7009890f6 100644
--- a/testing/mozharness/mozharness/mozilla/testing/raptor.py
+++ b/testing/mozharness/mozharness/mozilla/testing/raptor.py
@@ -299,6 +299,8 @@ class Raptor(TestingMixin, MercurialScript, CodeCoverageMixin):
     # clobber defined in BaseScript
 
     def download_and_extract(self, extract_dirs=None, suite_categories=None):
+        if 'MOZ_FETCHES' in os.environ:
+            self.fetch_content()
         return super(Raptor, self).download_and_extract(
             suite_categories=['common', 'raptor']
         )