diff --git a/edx_arch_experiments/codejail_service/tests/test_course_library.zip b/edx_arch_experiments/codejail_service/tests/test_course_library.zip
new file mode 100644
index 0000000..42409e3
Binary files /dev/null and b/edx_arch_experiments/codejail_service/tests/test_course_library.zip differ
diff --git a/edx_arch_experiments/codejail_service/tests/test_views.py b/edx_arch_experiments/codejail_service/tests/test_views.py
new file mode 100644
index 0000000..0aa005d
--- /dev/null
+++ b/edx_arch_experiments/codejail_service/tests/test_views.py
@@ -0,0 +1,141 @@
+"""
+Test codejail service views.
+"""
+
+import json
+import textwrap
+from os import path
+
+import ddt
+from django.contrib.auth import get_user_model
+from django.test import TestCase, override_settings
+from django.urls import reverse
+from rest_framework.test import APIClient
+
+from edx_arch_experiments.codejail_service import views
+
+
+@override_settings(
+    ROOT_URLCONF='edx_arch_experiments.codejail_service.urls',
+    MIDDLEWARE=[
+        'django.contrib.sessions.middleware.SessionMiddleware',
+    ],
+)
+@ddt.ddt
+class TestExecService(TestCase):
+    """Test the v0 code exec view."""
+
+    def setUp(self):
+        super().setUp()
+        user_model = get_user_model()
+        self.admin_user = user_model.objects.create_user('cms_worker', is_staff=True)
+        self.other_user = user_model.objects.create_user('student', is_staff=False)
+        self.standard_params = {'code': 'retval = 3 + 4', 'globals_dict': {}}
+
+    def _test_codejail_api(self, *, user=None, files=None, skip_auth=False, params=None, exp_status, exp_body):
+        """
+        Call the view and make assertions.
+
+        Arguments:
+            user: User to authenticate as when calling view (None for unauthenticated)
+            exp_status: Assert that the response HTTP status code is this value
+            exp_body: Assert that the response body JSON is this value
+        """
+        assert not (user and skip_auth)
+
+        client = APIClient()
+        user = user or self.admin_user
+        if not skip_auth:
+            client.force_authenticate(user)
+
+        params = self.standard_params if params is None else params
+        payload = json.dumps(params)
+        req_body = {'payload': payload, **(files or {})}
+
+        resp = client.post(reverse('code_exec_v0'), req_body, format='multipart')
+
+        assert resp.status_code == exp_status
+        assert json.loads(resp.content) == exp_body
+
+    def test_success(self):
+        """Regular successful call."""
+        self._test_codejail_api(
+            exp_status=200, exp_body={'globals_dict': {'retval': 7}},
+        )
+
+    @override_settings(CODEJAIL_SERVICE_ENABLED=False)
+    def test_feature_disabled(self):
+        """Service can be disabled."""
+        self._test_codejail_api(
+            exp_status=500, exp_body={'error': "Codejail service not enabled"},
+        )
+
+    @override_settings(ENABLE_CODEJAIL_REST_SERVICE=True)
+    def test_misconfigured_as_relay(self):
+        """Don't accept codejail requests if we're going to send them elsewhere."""
+        self._test_codejail_api(
+            exp_status=500, exp_body={'error': "Codejail service is misconfigured. (Refusing to act as relay.)"},
+        )
+
+    def test_unauthenticated(self):
+        """Anonymous requests are rejected."""
+        self._test_codejail_api(
+            skip_auth=True,
+            exp_status=403, exp_body={'detail': "Authentication credentials were not provided."},
+        )
+
+    def test_unprivileged(self):
+        """Anonymous requests are rejected."""
+        self._test_codejail_api(
+            user=self.other_user,
+            exp_status=403, exp_body={'detail': "You do not have permission to perform this action."},
+        )
+
+    def test_unsafely(self):
+        """unsafely=true is rejected"""
+        self._test_codejail_api(
+            params=dict(**self.standard_params, unsafely=True),
+            exp_status=400, exp_body={'error': "Refusing codejail execution with unsafely=true"},
+        )
+
+    @ddt.unpack
+    @ddt.data(
+        ({'globals_dict': {}}, 'code'),
+        ({'code': 'retval = 3 + 4'}, 'globals_dict'),
+        ({}, 'code'),
+    )
+    def test_missing_params(self, params, missing):
+        """code and globals_dict are required"""
+        self._test_codejail_api(
+            params=params,
+            exp_status=400, exp_body={
+                'error': f"Payload JSON did not match schema: '{missing}' is a required property",
+            },
+        )
+
+    def test_extra_files(self):
+        # "Course library" containing `course_library.triangular_number`.
+        #
+        # It's tempting to use zipfile to write to an io.BytesIO so
+        # that the test library is in plaintext. Django's request
+        # factory will indeed see that as a file to use in a multipart
+        # upload, but it will see it as an empty bytestring. (read()
+        # returns empty bytestring, while getvalue() returns the
+        # desired data). So instead we just have a small zip file on
+        # disk here.
+        library_path = path.join(path.dirname(__file__), 'test_course_library.zip')
+
+        with open(library_path, 'rb') as lib_zip:
+            self._test_codejail_api(
+                params={
+                    'code': textwrap.dedent("""
+                        from course_library import triangular_number
+
+                        result = triangular_number(6)
+                    """),
+                    'globals_dict': {},
+                    'python_path': ['python_lib.zip'],
+                },
+                files={'python_lib.zip': lib_zip},
+                exp_status=200, exp_body={'globals_dict': {'result': 21}},
+            )
diff --git a/edx_arch_experiments/codejail_service/views.py b/edx_arch_experiments/codejail_service/views.py
index 44b6c58..a67afa4 100644
--- a/edx_arch_experiments/codejail_service/views.py
+++ b/edx_arch_experiments/codejail_service/views.py
@@ -6,10 +6,11 @@
 import logging
 from copy import deepcopy
 
-import jsonschema
 from codejail.safe_exec import SafeExecException, safe_exec
 from django.conf import settings
 from edx_toggles.toggles import SettingToggle
+from jsonschema.exceptions import best_match as json_error_best_match
+from jsonschema.validators import Draft202012Validator
 from rest_framework.decorators import api_view, parser_classes, permission_classes
 from rest_framework.parsers import FormParser, MultiPartParser
 from rest_framework.permissions import IsAdminUser
@@ -61,6 +62,11 @@
     },
     'required': ['code', 'globals_dict'],
 }
+# Use this rather than jsonschema.validate, since that would check the schema
+# every time it is called. Best to do it just once at startup.
+Draft202012Validator.check_schema(payload_schema)
+payload_validator = Draft202012Validator(payload_schema)
+
 
 # A note on the authorization model used here:
 #
@@ -126,7 +132,9 @@ def code_exec_view_v0(request):
 
     params_json = request.data['payload']
     params = json.loads(params_json)
-    jsonschema.validate(params, payload_schema)
+
+    if json_error := json_error_best_match(payload_validator.iter_errors(params)):
+        return Response({'error': f"Payload JSON did not match schema: {json_error.message}"}, status=400)
 
     complete_code = params['code']  # includes standard prolog
     input_globals_dict = params['globals_dict']
@@ -135,7 +143,9 @@ def code_exec_view_v0(request):
     slug = params.get('slug')
     unsafely = params.get('unsafely')
 
-    extra_files = request.FILES
+    # Convert to a list of (string, bytestring) pairs. Any duplicated file names
+    # are resolved as last-wins.
+    extra_files = [(filename, file.read()) for filename, file in request.FILES.items()]
 
     # Far too dangerous to allow unsafe executions to come in over the
     # network, no matter who we think the caller is. The caller is the
@@ -154,8 +164,8 @@ def code_exec_view_v0(request):
             slug=slug,
         )
     except SafeExecException as e:
-        log.debug("CodejailService execution failed with: {e!r}")
+        log.debug("CodejailService execution failed for {slug=} with: {e!r}")
         return Response({'emsg': f"Code jail execution failed: {e!r}"})
 
-    log.debug("CodejailService execution succeeded, with globals={output_globals_dict!r}")
+    log.debug("CodejailService execution succeeded for {slug=}, with globals={output_globals_dict!r}")
     return Response({'globals_dict': output_globals_dict})
diff --git a/requirements/base.txt b/requirements/base.txt
index 49f7249..9fbaedb 100644
--- a/requirements/base.txt
+++ b/requirements/base.txt
@@ -61,7 +61,7 @@ edx-django-utils==5.9.0
     #   -r requirements/base.in
     #   edx-drf-extensions
     #   edx-toggles
-edx-drf-extensions==9.0.1
+edx-drf-extensions==9.1.2
     # via -r requirements/base.in
 edx-opaque-keys==2.5.1
     # via edx-drf-extensions
@@ -73,7 +73,7 @@ importlib-resources==6.1.1
     # via
     #   jsonschema
     #   jsonschema-specifications
-jinja2==3.1.2
+jinja2==3.1.3
     # via code-annotations
 jsonschema==4.20.0
     # via -r requirements/base.in
@@ -81,7 +81,7 @@ jsonschema-specifications==2023.12.1
     # via jsonschema
 markupsafe==2.1.3
     # via jinja2
-newrelic==9.3.0
+newrelic==9.4.0
     # via edx-django-utils
 pbr==6.0.0
     # via stevedore
@@ -108,7 +108,7 @@ pytz==2023.3.post1
     #   djangorestframework
 pyyaml==6.0.1
     # via code-annotations
-referencing==0.32.0
+referencing==0.32.1
     # via
     #   jsonschema
     #   jsonschema-specifications
diff --git a/requirements/dev.txt b/requirements/dev.txt
index c6043d6..ca87a77 100644
--- a/requirements/dev.txt
+++ b/requirements/dev.txt
@@ -76,6 +76,8 @@ cryptography==41.0.7
     #   -r requirements/quality.txt
     #   pyjwt
     #   secretstorage
+ddt==1.7.1
+    # via -r requirements/quality.txt
 diff-cover==8.0.2
     # via -r requirements/dev.in
 dill==0.3.7
@@ -129,7 +131,7 @@ edx-django-utils==5.9.0
     #   -r requirements/quality.txt
     #   edx-drf-extensions
     #   edx-toggles
-edx-drf-extensions==9.0.1
+edx-drf-extensions==9.1.2
     # via -r requirements/quality.txt
 edx-i18n-tools==1.3.0
     # via -r requirements/dev.in
@@ -184,7 +186,7 @@ jeepney==0.8.0
     #   -r requirements/quality.txt
     #   keyring
     #   secretstorage
-jinja2==3.1.2
+jinja2==3.1.3
     # via
     #   -r requirements/quality.txt
     #   code-annotations
@@ -199,7 +201,7 @@ keyring==24.3.0
     # via
     #   -r requirements/quality.txt
     #   twine
-lxml==5.0.0
+lxml==5.1.0
     # via edx-i18n-tools
 markdown-it-py==3.0.0
     # via
@@ -217,11 +219,11 @@ mdurl==0.1.2
     # via
     #   -r requirements/quality.txt
     #   markdown-it-py
-more-itertools==10.1.0
+more-itertools==10.2.0
     # via
     #   -r requirements/quality.txt
     #   jaraco-classes
-newrelic==9.3.0
+newrelic==9.4.0
     # via
     #   -r requirements/quality.txt
     #   edx-django-utils
@@ -357,7 +359,7 @@ readme-renderer==42.0
     # via
     #   -r requirements/quality.txt
     #   twine
-referencing==0.32.0
+referencing==0.32.1
     # via
     #   -r requirements/quality.txt
     #   jsonschema
diff --git a/requirements/doc.txt b/requirements/doc.txt
index 3d06a41..37a1ae6 100644
--- a/requirements/doc.txt
+++ b/requirements/doc.txt
@@ -48,6 +48,8 @@ cryptography==41.0.7
     # via
     #   -r requirements/test.txt
     #   pyjwt
+ddt==1.7.1
+    # via -r requirements/test.txt
 django==3.2.23
     # via
     #   -c https://raw.githubusercontent.com/edx/edx-lint/master/edx_lint/files/common_constraints.txt
@@ -94,7 +96,7 @@ edx-django-utils==5.9.0
     #   -r requirements/test.txt
     #   edx-drf-extensions
     #   edx-toggles
-edx-drf-extensions==9.0.1
+edx-drf-extensions==9.1.2
     # via -r requirements/test.txt
 edx-opaque-keys==2.5.1
     # via
@@ -125,7 +127,7 @@ iniconfig==2.0.0
     # via
     #   -r requirements/test.txt
     #   pytest
-jinja2==3.1.2
+jinja2==3.1.3
     # via
     #   -r requirements/test.txt
     #   code-annotations
@@ -140,7 +142,7 @@ markupsafe==2.1.3
     # via
     #   -r requirements/test.txt
     #   jinja2
-newrelic==9.3.0
+newrelic==9.4.0
     # via
     #   -r requirements/test.txt
     #   edx-django-utils
@@ -215,7 +217,7 @@ pyyaml==6.0.1
     #   code-annotations
 readme-renderer==42.0
     # via -r requirements/doc.in
-referencing==0.32.0
+referencing==0.32.1
     # via
     #   -r requirements/test.txt
     #   jsonschema
diff --git a/requirements/quality.txt b/requirements/quality.txt
index a6dd1e6..4a4ef9b 100644
--- a/requirements/quality.txt
+++ b/requirements/quality.txt
@@ -54,6 +54,8 @@ cryptography==41.0.7
     #   -r requirements/test.txt
     #   pyjwt
     #   secretstorage
+ddt==1.7.1
+    # via -r requirements/test.txt
 dill==0.3.7
     # via pylint
 django==3.2.23
@@ -96,7 +98,7 @@ edx-django-utils==5.9.0
     #   -r requirements/test.txt
     #   edx-drf-extensions
     #   edx-toggles
-edx-drf-extensions==9.0.1
+edx-drf-extensions==9.1.2
     # via -r requirements/test.txt
 edx-lint==5.3.6
     # via -r requirements/quality.in
@@ -138,7 +140,7 @@ jeepney==0.8.0
     # via
     #   keyring
     #   secretstorage
-jinja2==3.1.2
+jinja2==3.1.3
     # via
     #   -r requirements/test.txt
     #   code-annotations
@@ -160,9 +162,9 @@ mccabe==0.7.0
     # via pylint
 mdurl==0.1.2
     # via markdown-it-py
-more-itertools==10.1.0
+more-itertools==10.2.0
     # via jaraco-classes
-newrelic==9.3.0
+newrelic==9.4.0
     # via
     #   -r requirements/test.txt
     #   edx-django-utils
@@ -256,7 +258,7 @@ pyyaml==6.0.1
     #   code-annotations
 readme-renderer==42.0
     # via twine
-referencing==0.32.0
+referencing==0.32.1
     # via
     #   -r requirements/test.txt
     #   jsonschema
diff --git a/requirements/scripts.txt b/requirements/scripts.txt
index 0847847..35ed440 100644
--- a/requirements/scripts.txt
+++ b/requirements/scripts.txt
@@ -85,7 +85,7 @@ edx-django-utils==5.9.0
     #   edx-drf-extensions
     #   edx-event-bus-kafka
     #   edx-toggles
-edx-drf-extensions==9.0.1
+edx-drf-extensions==9.1.2
     # via -r requirements/base.txt
 edx-event-bus-kafka==5.5.0
     # via -r requirements/scripts.in
@@ -98,7 +98,7 @@ edx-toggles==5.1.0
     # via
     #   -r requirements/base.txt
     #   edx-event-bus-kafka
-fastavro==1.9.2
+fastavro==1.9.3
     # via
     #   confluent-kafka
     #   openedx-events
@@ -111,7 +111,7 @@ importlib-resources==6.1.1
     #   -r requirements/base.txt
     #   jsonschema
     #   jsonschema-specifications
-jinja2==3.1.2
+jinja2==3.1.3
     # via
     #   -r requirements/base.txt
     #   code-annotations
@@ -125,7 +125,7 @@ markupsafe==2.1.3
     # via
     #   -r requirements/base.txt
     #   jinja2
-newrelic==9.3.0
+newrelic==9.4.0
     # via
     #   -r requirements/base.txt
     #   edx-django-utils
@@ -174,7 +174,7 @@ pyyaml==6.0.1
     # via
     #   -r requirements/base.txt
     #   code-annotations
-referencing==0.32.0
+referencing==0.32.1
     # via
     #   -r requirements/base.txt
     #   jsonschema
diff --git a/requirements/test.in b/requirements/test.in
index 6797160..f2e6548 100644
--- a/requirements/test.in
+++ b/requirements/test.in
@@ -6,3 +6,4 @@
 pytest-cov                # pytest extension for code coverage statistics
 pytest-django             # pytest extension for better Django support
 code-annotations          # provides commands used by the pii_check make target.
+ddt                       # data-driven tests
\ No newline at end of file
diff --git a/requirements/test.txt b/requirements/test.txt
index f88fdf7..86e1fdd 100644
--- a/requirements/test.txt
+++ b/requirements/test.txt
@@ -44,6 +44,8 @@ cryptography==41.0.7
     # via
     #   -r requirements/base.txt
     #   pyjwt
+ddt==1.7.1
+    # via -r requirements/test.in
     # via
     #   -c https://raw.githubusercontent.com/edx/edx-lint/master/edx_lint/files/common_constraints.txt
     #   -r requirements/base.txt
@@ -81,7 +83,7 @@ edx-django-utils==5.9.0
     #   -r requirements/base.txt
     #   edx-drf-extensions
     #   edx-toggles
-edx-drf-extensions==9.0.1
+edx-drf-extensions==9.1.2
     # via -r requirements/base.txt
 edx-opaque-keys==2.5.1
     # via
@@ -102,7 +104,7 @@ importlib-resources==6.1.1
     #   jsonschema-specifications
 iniconfig==2.0.0
     # via pytest
-jinja2==3.1.2
+jinja2==3.1.3
     # via
     #   -r requirements/base.txt
     #   code-annotations
@@ -116,7 +118,7 @@ markupsafe==2.1.3
     # via
     #   -r requirements/base.txt
     #   jinja2
-newrelic==9.3.0
+newrelic==9.4.0
     # via
     #   -r requirements/base.txt
     #   edx-django-utils
@@ -175,7 +177,7 @@ pyyaml==6.0.1
     # via
     #   -r requirements/base.txt
     #   code-annotations
-referencing==0.32.0
+referencing==0.32.1
     # via
     #   -r requirements/base.txt
     #   jsonschema