Merge branch 'pl-json-schema-matcher' into 'master'

Improve schema matcher to display errors

See merge request gitlab-org/gitlab!79839

spec/fixtures/api/schemas/public_api/v4/merge_request.json

 {
   "type": "object",
-  "properties" : {
   "properties" : {
     "id": { "type": "integer" },
     "iid": { "type": "integer" },
@@ -77,8 +76,9 @@
       "additionalProperties": false
     },
     "assignees": {
+      "type": "array",
       "items": {
-          "$ref": "./merge_request.json"
+        "$ref": "user/basic.json"
       }
     },
     "source_project_id": { "type": "integer" },
@@ -91,21 +91,10 @@
     },
     "work_in_progress": { "type": "boolean" },
     "milestone": {
-        "type": ["object", "null"],
-        "properties": {
-          "id": { "type": "integer" },
-          "iid": { "type": "integer" },
-          "project_id": { "type": ["integer", "null"] },
-          "group_id": { "type": ["integer", "null"] },
-          "title": { "type": "string" },
-          "description": { "type": ["string", "null"] },
-          "state": { "type": "string" },
-          "created_at": { "type": "string", "format": "date-time" },
-          "updated_at": { "type": "string", "format": "date-time" },
-          "due_date": { "type": "string", "format": "date-time" },
-          "start_date": { "type": "string", "format": "date-time" }
-        },
-        "additionalProperties": false
+      "oneOf": [
+        { "type": "null" },
+        { "$ref": "milestone.json" }
+      ]
     },
     "merge_when_pipeline_succeeds": { "type": "boolean" },
     "merge_status": { "type": "string" },
@@ -148,5 +137,4 @@
       { "$ref": "pipeline/detail.json" }
     ]
   }
-  }
 }

spec/support/matchers/schema_matcher.rb

@@ -36,12 +36,38 @@ end
 
 RSpec::Matchers.define :match_response_schema do |schema, dir: nil, **options|
   match do |response|
-    schema_path = Pathname.new(SchemaPath.expand(schema, dir))
-    validator = SchemaPath.validator(schema_path)
+    @schema_path = Pathname.new(SchemaPath.expand(schema, dir))
+    validator = SchemaPath.validator(@schema_path)
 
-    data = Gitlab::Json.parse(response.body)
+    @data = Gitlab::Json.parse(response.body)
 
-    validator.valid?(data)
+    @schema_errors = validator.validate(@data)
+    @schema_errors.none?
+  end
+
+  failure_message do |actual|
+    message = []
+
+    message << <<~MESSAGE
+      expected JSON response to match schema #{@schema_path.inspect}.
+
+      JSON input: #{Gitlab::Json.pretty_generate(@data).indent(2)}
+
+      Schema errors:
+    MESSAGE
+
+    @schema_errors.each do |error|
+      property_name, actual_value = error.values_at('data_pointer', 'data')
+      property_name = 'root' if property_name.empty?
+
+      message << <<~MESSAGE
+        Property: #{property_name}
+          Actual value: #{Gitlab::Json.pretty_generate(actual_value).indent(2)}
+          Error: #{JSONSchemer::Errors.pretty(error)}
+      MESSAGE
+    end
+
+    message.join("\n")
   end
 end