diff --git a/.circleci/config.yml b/.circleci/config.yml
index 5dcaacb6a..7039d2e80 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -93,7 +93,10 @@ jobs:
           # if the working directory is not readable.
           working_directory: "/tmp"
           command: |
-            /tmp/project/.circleci/run-tests.sh "${TAHOE_LAFS_TOX_ENVIRONMENT}" "${TAHOE_LAFS_TOX_ARGS}"
+            /tmp/project/.circleci/run-tests.sh \
+                /tmp/artifacts \
+                "${TAHOE_LAFS_TOX_ENVIRONMENT}" \
+                "${TAHOE_LAFS_TOX_ARGS}"
 
       - store_test_results: &STORE_TEST_RESULTS
           path: "/tmp/artifacts/junit"
diff --git a/.circleci/run-tests.sh b/.circleci/run-tests.sh
index fa38edf53..29b4e2507 100755
--- a/.circleci/run-tests.sh
+++ b/.circleci/run-tests.sh
@@ -1,5 +1,8 @@
 #!/bin/bash -e
 
+ARTIFACTS=$1
+shift
+
 TAHOE_LAFS_TOX_ENVIRONMENT=$1
 shift
 
@@ -18,11 +21,19 @@ sudo TAHOE_LAFS_TRIAL_ARGS="--reporter=subunit" \
      --user nobody \
      /tmp/tests/bin/tox \
      -c /tmp/project/tox.ini \
-     --result-json /tmp/tox-result.json \
+     --result-json "${ARTIFACTS}"/tox-result.json \
      --workdir /tmp/tahoe-lafs.tox \
      -e "${TAHOE_LAFS_TOX_ENVIRONMENT}" \
      ${TAHOE_LAFS_TOX_ARGS}
 
+TOX_JSON="${ARTIFACTS}"/tox-result.json
+SUBUNIT1="${ARTIFACTS}"/results.subunit1
+SUBUNIT2="${ARTIFACTS}"/results.subunit2
+
+# Use an intermediate directory here because CircleCI extracts some label
+# information from its name.
+JUNITXML="${ARTIFACTS}"/junit/unittests/results.xml
+
 # Extract the test process output which should be subunit1-format.
 /tmp/tests/bin/python -c '
 from json import load
@@ -31,13 +42,11 @@ result = load(stdin)
 for environ in argv[1].split(","):
     messy_output = result["testenvs"][environ]["test"][-1]["output"]
     stdout.write(messy_output.split("\n", 3)[3].strip() + "\n")
-' "${TAHOE_LAFS_TOX_ENVIRONMENT}" < /tmp/tox-result.json > /tmp/results.subunit1
+' "${TAHOE_LAFS_TOX_ENVIRONMENT}" < "${TOX_JSON}" > "${SUBUNIT1}"
 
 # Upgrade subunit version because subunit2junitxml only works on subunit2
-/tmp/tests/bin/subunit-1to2 < /tmp/results.subunit1 > /tmp/results.subunit2
+/tmp/tests/bin/subunit-1to2 < "${SUBUNIT1}" > "${SUBUNIT2}"
 
-# Create a junitxml results area.  Put these results in a subdirectory of the
-# ultimate location because CircleCI extracts some label information from the
-# subdirectory name.
-mkdir -p /tmp/artifacts/junit/unittests
-/tmp/tests/bin/subunit2junitxml < /tmp/results.subunit2 > /tmp/artifacts/junit/unittests/results.xml
+# Create a junitxml results area.
+mkdir -p "$(dirname "${JUNITXML}")"
+/tmp/tests/bin/subunit2junitxml < "${SUBUNIT2}" > "${JUNITXML}"