Fix two scenarios where null values were causing errors

src/transformer/events/mod_assign/assignment_graded.php

@@ -29,10 +29,16 @@ function assignment_graded(array $config, \stdClass $event) {
     $assignment = $repo->read_record_by_id('assign', $grade->assignment);
     $lang = utils\get_course_lang($course);
 
-    $gradecomment = $repo->read_record('assignfeedback_comments', [
-        'assignment' => $grade->assignment,
-        'grade' => $grade->id
-    ])->commenttext;
+    $gradecomment = null;
+    try {
+        $gradecomment = $repo->read_record('assignfeedback_comments', [
+            'assignment' => $grade->assignment,
+            'grade' => $grade->id
+        ])->commenttext;
+    } catch (\Exception $e) {
+        $gradecomment = null;
+    }
+
     $gradeitems = $repo->read_record('grade_items', [
         'itemmodule' => 'assign',
         'iteminstance' => $grade->assignment
@@ -63,8 +69,7 @@ function assignment_graded(array $config, \stdClass $event) {
                 'raw' => $scoreraw
             ],
             'completion' => true,
-            'success' => $success,
-            'response' => $gradecomment
+            'success' => $success
         ],
         'timestamp' => utils\get_event_timestamp($event),
         'context' => [
@@ -86,6 +91,10 @@ function assignment_graded(array $config, \stdClass $event) {
         ]
     ];
 
+    if (!is_null($gradecomment)) {
+        $statement['result']['response'] = $gradecomment;
+    }
+
     // Only include min score if raw score is valid for that min.
     if ($scoreraw >= $scoremin) {
         $statement['result']['score']['min'] = $scoremin;

src/transformer/events/mod_quiz/question_answered/essay.php

@@ -29,6 +29,8 @@ function essay(array $config, \stdClass $event, \stdClass $questionattempt, \std
     $coursemodule = $repo->read_record_by_id('course_modules', $event->contextinstanceid);
     $lang = utils\get_course_lang($course);
 
+    $responsesummary = is_null($questionattempt->responsesummary) ? '' : $questionattempt->responsesummary;
+
     return [[
         'actor' => utils\get_user($config, $user),
         'verb' => [
@@ -49,8 +51,8 @@ function essay(array $config, \stdClass $event, \stdClass $questionattempt, \std
         ],
         'timestamp' => utils\get_event_timestamp($event),
         'result' => [
-            'response' => $questionattempt->responsesummary,
-            'completion' => $questionattempt->responsesummary !== '',
+            'response' => $responsesummary,
+            'completion' => $responsesummary !== '',
         ],
         'context' => [
             'platform' => $config['source_name'],

tests/mod_assign/assignment_graded/existing_assignment_graded/test.php → tests/mod_assign/assignment_graded/existing_assignment_graded_comment/test.php

@@ -14,7 +14,7 @@
 // You should have received a copy of the GNU General Public License
 // along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
 
-namespace tests\mod_assign\assignment_graded\existing_assignment_graded;
+namespace tests\mod_assign\assignment_graded\existing_assignment_graded_comment;
 defined('MOODLE_INTERNAL') || die();
 
 class test extends \tests\xapi_test_case {

tests/mod_assign/assignment_graded/existing_assignment_graded_nocomment/data.json

@@ -0,0 +1,55 @@
+{
+    "user": [
+        {
+            "id": 1,
+            "firstname": "test_fullname",
+            "email": "[email protected]"
+        },
+        {
+            "id": 2,
+            "firstname": "test2_fullname",
+            "email": "[email protected]"
+        }
+    ],
+    "course": [
+        {
+            "id": 1,
+            "fullname": "test_name",
+            "lang": "en"
+        }
+    ],
+    "course_modules": [
+        {
+            "id": 1,
+            "course": 1,
+            "module": 1,
+            "instance": 1
+        }
+    ],
+    "assign": [
+        {
+            "id": 1,
+            "name": "test_name"
+        }
+    ],
+    "grade": [
+        {
+            "id": 1,
+            "userid": 2,
+            "assignment": 1,
+            "grade": 1
+        }
+    ],
+    "assignfeedback_comments": [
+    ],
+    "grade_items": [
+        {
+            "id": 1,
+            "itemmodule": "assign",
+            "iteminstance": 1,
+            "grademin": 0,
+            "grademax": 2,
+            "gradepass": 1
+        }
+    ]
+}

tests/mod_assign/assignment_graded/existing_assignment_graded_nocomment/event.json

@@ -0,0 +1,10 @@
+{
+    "id": 1,
+    "userid": 1,
+    "courseid": 1,
+    "timecreated": 1433946701,
+    "objecttable": "grade",
+    "objectid": 1,
+    "contextinstanceid": 1,
+    "eventname": "\\mod_assign\\event\\submission_graded"
+}

tests/mod_assign/assignment_graded/existing_assignment_graded_nocomment/statements.json

@@ -0,0 +1,89 @@
+[
+    {
+        "actor": {
+            "name": "test2_fullname",
+            "account": {
+                "homePage": "http:\/\/www.example.org",
+                "name": "2"
+            }
+        },
+        "verb": {
+            "id": "http:\/\/adlnet.gov\/expapi\/verbs\/scored",
+            "display": {
+                "en": "attained grade for"
+            }
+        },
+        "object": {
+            "id": "http:\/\/www.example.org\/mod\/assign\/view.php?id=1",
+            "definition": {
+                "type": "http:\/\/adlnet.gov\/expapi\/activities\/assessment",
+                "name": {
+                    "en": "test_name"
+                }
+            }
+        },
+        "result": {
+            "score": {
+                "raw": 1,
+                "min": 0,
+                "max": 2,
+                "scaled": 0.5
+            },
+            "completion": true,
+            "success": true
+        },
+        "timestamp": "2015-06-10T15:31:41+01:00",
+        "context": {
+            "instructor": {
+                "name": "test_fullname",
+                "account": {
+                    "homePage": "http:\/\/www.example.org",
+                    "name": "1"
+                }
+            },
+            "platform": "Moodle",
+            "language": "en",
+            "extensions": {
+                "http:\/\/lrs.learninglocker.net\/define\/extensions\/info": {
+                    "http:\/\/moodle.org": "1.0.0",
+                    "https:\/\/github.com\/xAPI-vle\/moodle-logstore_xapi": "0.0.0-development",
+                    "event_name": "\\mod_assign\\event\\submission_graded",
+                    "event_function": "\\src\\transformer\\events\\mod_assign\\assignment_graded"
+                }
+            },
+            "contextActivities": {
+                "grouping": [
+                    {
+                        "id": "http:\/\/www.example.org",
+                        "definition": {
+                            "type": "http:\/\/id.tincanapi.com\/activitytype\/lms",
+                            "name": {
+                                "en": "test_name"
+                            }
+                        }
+                    },
+                    {
+                        "id": "http:\/\/www.example.org\/course\/view.php?id=1",
+                        "definition": {
+                            "type": "http:\/\/id.tincanapi.com\/activitytype\/lms\/course",
+                            "name": {
+                                "en": "test_name"
+                            }
+                        }
+                    }
+                ],
+                "category": [
+                    {
+                        "id": "http:\/\/moodle.org",
+                        "definition": {
+                            "type": "http:\/\/id.tincanapi.com\/activitytype\/source",
+                            "name": {
+                                "en": "Moodle"
+                            }
+                        }
+                    }
+                ]
+            }
+        }
+    }
+]

tests/mod_assign/assignment_graded/existing_assignment_graded_nocomment/test.php

@@ -0,0 +1,24 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+namespace tests\mod_assign\assignment_graded\existing_assignment_graded_nocomment;
+defined('MOODLE_INTERNAL') || die();
+
+class test extends \tests\xapi_test_case {
+    protected function get_test_dir() {
+        return __DIR__;
+    }
+}

tests/mod_quiz/attempt_submitted/essay_null_response/data.json

@@ -0,0 +1,78 @@
+{
+    "user": [
+        {
+            "id": 1,
+            "firstname": "test_fullname",
+            "email": "[email protected]"
+        }
+    ],
+    "course": [
+        {
+            "id": 1,
+            "fullname": "test_name",
+            "lang": "en"
+        }
+    ],
+    "course_modules": [
+        {
+            "id": 1,
+            "course": 1,
+            "module": 1,
+            "instance": 1
+        }
+    ],
+    "modules": [
+        {
+            "id": 1,
+            "name": "quiz"
+        }
+    ],
+    "quiz_attempts": [
+        {
+            "id": 1,
+            "quiz": 1,
+            "uniqueid": 1,
+            "sumgrades": 50,
+            "state": "finished",
+            "timefinish": 1,
+            "timestart": 0
+        }
+    ],
+    "question_usages": [
+        {
+            "id": 1
+
+        }
+    ],
+    "quiz": [
+        {
+            "id": 1,
+            "name": "test_quiz_name"
+        }
+    ],
+    "grade_items": [
+        {
+            "id": 1,
+            "iteminstance": 1,
+            "itemmodule": "quiz",
+            "grademin": 0,
+            "grademax": 100,
+            "gradepass": 50
+        }
+    ],
+    "question_attempts": [
+        {
+            "id": 1,
+            "questionusageid": 1,
+            "questionid": 1,
+            "responsesummary": null
+        }
+    ],
+    "question": [
+        {
+            "id": 1,
+            "qtype": "essay",
+            "questiontext": "test_question"
+        }
+    ]
+}

tests/mod_quiz/attempt_submitted/essay_null_response/event.json

@@ -0,0 +1,10 @@
+{
+    "id": 1,
+    "relateduserid": 1,
+    "courseid": 1,
+    "timecreated": 1433946701,
+    "objecttable": "attempt",
+    "objectid": 1,
+    "contextinstanceid": 1,
+    "eventname": "\\mod_quiz\\event\\attempt_submitted"
+}