Create tests to validate schema examples (#348)

Add a unit test to validate if the examples provided in the config
modules are conforming to the concatenated schema of all config
modules. The rationale behind that is not only to verify if the
examples are correctly written but to assert that no config schema
is interfering with each other.

Failures in validate_cloudconfig_schema raise the
SchemaValidationError by using strict=True, so I have
only called the function passing the right schema examples to
validate.

This branch also fixes an invalid schema example in cc_snap.

LP: #1876412

2 files changed, 21 insertions, 2 deletions

diff --git a/cloudinit/config/cc_snap.py b/cloudinit/config/cc_snap.py
index 90724b81..fbe7787a 100644
--- a/cloudinit/config/cc_snap.py
+++ b/cloudinit/config/cc_snap.py
@@ -61,9 +61,9 @@ schema = {
         snap:
             assertions:
               00: |
-              signed_assertion_blob_here
+                signed_assertion_blob_here
               02: |
-              signed_assertion_blob_here
+                signed_assertion_blob_here
             commands:
               00: snap create-user --sudoer --known <snap-user>@mydomain.com
               01: snap install canonical-livepatch
diff --git a/tests/unittests/test_handler/test_schema.py b/tests/unittests/test_handler/test_schema.py
index 1059fb8b..ae3838d8 100644
--- a/tests/unittests/test_handler/test_schema.py
+++ b/tests/unittests/test_handler/test_schema.py
@@ -10,6 +10,7 @@ from cloudinit.tests.helpers import CiTestCase, mock, skipUnlessJsonSchema
 
 from copy import copy
 import os
+import pytest
 from io import StringIO
 from textwrap import dedent
 from yaml import safe_load
@@ -112,6 +113,24 @@ class ValidateCloudConfigSchemaTest(CiTestCase):
             str(context_mgr.exception))
 
 
+class TestCloudConfigExamples:
+
+    SCHEMA = get_schema()
+    PARAMS = [
+        (schema["id"], example)
+        for schema in SCHEMA["allOf"] for example in schema["examples"]]
+
+    @pytest.mark.parametrize("schema_id,example", PARAMS)
+    @skipUnlessJsonSchema()
+    def test_validateconfig_schema_of_example(self, schema_id, example):
+        """ For a given example in a config module we test if it is valid
+        according to the unified schema of all config modules
+        """
+        config_load = safe_load(example)
+        validate_cloudconfig_schema(
+            config_load, TestCloudConfigExamples.SCHEMA, strict=True)
+
+
 class ValidateCloudConfigFileTest(CiTestCase):
     """Tests for validate_cloudconfig_file."""