diff --git a/roles/ensure-tox/README.rst b/roles/ensure-tox/README.rst
index b949c90cf..410a60421 100644
--- a/roles/ensure-tox/README.rst
+++ b/roles/ensure-tox/README.rst
@@ -6,13 +6,12 @@ virtual environment for the current user.
 **Role Variables**
 
 .. zuul:rolevar:: ensure_tox_version
-   :default: '<4'
+   :default: ''
 
    Version specifier to select the version of tox. For example if your
    project is not compatible with tox v4 you can set this value to
-   `<4` to install the latest v3 release. We have started this value
-   at `<4` for maximum compatibility, but expect it to change to ''
-   in the future when tox v4 is better understood.
+   `<4` to install the latest v3 release. The default is '' which
+   installs latest.
 
 .. zuul:rolevar:: tox_prefer_python2
    :default: False
diff --git a/roles/ensure-tox/defaults/main.yaml b/roles/ensure-tox/defaults/main.yaml
index e9830eddf..055b54f1a 100644
--- a/roles/ensure-tox/defaults/main.yaml
+++ b/roles/ensure-tox/defaults/main.yaml
@@ -1,5 +1,5 @@
 tox_executable: tox
-ensure_tox_version: '<4'
+ensure_tox_version: ''
 tox_venv_path: '{{ ansible_user_dir }}/.local/tox'
 tox_prefer_python2: false
 ensure_global_symlinks: false
diff --git a/test-playbooks/python/fetch-tox-output.yaml b/test-playbooks/python/fetch-tox-output.yaml
index 537e8ba9f..86b0c764a 100644
--- a/test-playbooks/python/fetch-tox-output.yaml
+++ b/test-playbooks/python/fetch-tox-output.yaml
@@ -56,14 +56,14 @@
   post_tasks:
     - name: Check for artifact on the test instance
       stat:
-        path: "{{ ansible_user_dir }}/zuul-output/logs/tox/venv/venv-0.log"
+        path: "{{ ansible_user_dir }}/zuul-output/logs/tox/venv/1-install_package.log"
       register: _test_artifact
       failed_when: not _test_artifact.stat.exists
       when: zuul_use_fetch_output
 
     - name: Check for artifact on the executor
       stat:
-        path: "{{ zuul.executor.log_root }}/tox/venv/venv-0.log"
+        path: "{{ zuul.executor.log_root }}/tox/venv/1-install_package.log"
       delegate_to: localhost
       register: _executor_artifact
       failed_when: not _executor_artifact.stat.exists
diff --git a/test-playbooks/python/tox.yaml b/test-playbooks/python/tox.yaml
index 955ee1337..ba0e59b8c 100644
--- a/test-playbooks/python/tox.yaml
+++ b/test-playbooks/python/tox.yaml
@@ -76,12 +76,22 @@
           register: ALL_status
           failed_when: ALL_status is changed
 
+    - name: Move test-playbooks/python/tox.ini to test-playbooks/python/foo.ini
+      # Tox 4 appears to have trouble when there is a tox.ini in the current
+      # dir and you run it with -c pointing at another file. Work around this
+      # to test the use of -c by moving the tox.ini to another location
+      # and -c'ing against that in the next task.
+      command: mv tox.ini foo.ini
+      args:
+        chdir: "{{ zuul.project.src_dir }}/test-playbooks/python/"
+
     - name: Run tox against a specific config file
       include_role:
         name: tox
       vars:
+        zuul_work_dir: "{{ zuul.project.src_dir }}/test-playbooks/python/"
         # Make sure the tox_config_file option works
-        tox_config_file: test-playbooks/python
+        tox_config_file: foo.ini
         tox_envlist: 'foo'
         # Make sure we test with verbose output even if the default changes
         tox_extra_args: '-vv'
diff --git a/zuul-tests.d/python-jobs.yaml b/zuul-tests.d/python-jobs.yaml
index aa156e4a1..22e25f608 100644
--- a/zuul-tests.d/python-jobs.yaml
+++ b/zuul-tests.d/python-jobs.yaml
@@ -350,6 +350,7 @@
     description: Test the tox role's sibling functionality
     files:
       - roles/tox/.*
+      - roles/ensure-tox/.*
       - tox.ini
       - test-playbooks/python/tox.yaml
       - test-playbooks/python/tox.ini