diff --git a/mod/forum/tests/portfolio_caller_test.php b/mod/forum/tests/portfolio_caller_test.php
new file mode 100644
index 00000000000..572068e64da
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+++ b/mod/forum/tests/portfolio_caller_test.php
@@ -0,0 +1,142 @@
+<?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/>.
+
+/**
+ * The portfolio forum tests.
+ *
+ * @package    mod_forum
+ * @copyright  2018 onwards Totara Learning Solutions LTD {@link http://www.totaralms.com/}
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ * @author     Brendan Cox <brendan.cox@totaralearning.com>
+ */
+
+defined('MOODLE_INTERNAL') || die();
+
+/**
+ * Class mod_forum_portfolio_caller_testcase
+ *
+ * Tests behaviour of the forum_portfolio_caller class.
+ */
+class mod_forum_portfolio_caller_testcase extends advanced_testcase {
+
+    /**
+     * Ensure that a file will be loaded in an instance of the caller when supplied valid and
+     * accessible post and attachment file ids.
+     */
+    public function test_file_in_user_post_is_loaded() {
+        global $CFG;
+        require_once($CFG->dirroot . '/mod/forum/locallib.php');
+        $this->resetAfterTest(true);
+
+        $user = $this->getDataGenerator()->create_user();
+        $course = $this->getDataGenerator()->create_course();
+        $forum = $this->getDataGenerator()->create_module('forum', array('course' => $course->id));
+        $context = context_module::instance($forum->cmid);
+
+        /* @var mod_forum_generator $forumgenerator */
+        $forumgenerator = $this->getDataGenerator()->get_plugin_generator('mod_forum');
+        $discussion = $forumgenerator->create_discussion(
+            array(
+                'course' => $course->id,
+                'forum' => $forum->id,
+                'userid' => $user->id,
+                'attachment' => 1
+            )
+        );
+
+        $fs = get_file_storage();
+        $dummy = (object) array(
+            'contextid' => $context->id,
+            'component' => 'mod_forum',
+            'filearea' => 'attachment',
+            'itemid' => $discussion->firstpost,
+            'filepath' => '/',
+            'filename' => 'myassignmnent.pdf'
+        );
+        $firstpostfile = $fs->create_file_from_string($dummy, 'Content of ' . $dummy->filename);
+
+        $caller = new forum_portfolio_caller(array(
+            'postid' => $discussion->firstpost,
+            'attachment' => $firstpostfile->get_id()
+        ));
+
+        $caller->load_data();
+        $this->assertEquals($caller->get_sha1_file(), $firstpostfile->get_contenthash());
+    }
+
+    /**
+     * Ensure that files will not be loaded if the supplied attachment id is for a file that is not attached to
+     * the supplied post id.
+     */
+    public function test_file_not_in_user_post_not_loaded() {
+        global $CFG;
+        require_once($CFG->dirroot . '/mod/forum/locallib.php');
+        $this->resetAfterTest(true);
+
+        $user = $this->getDataGenerator()->create_user();
+        $course = $this->getDataGenerator()->create_course();
+        $forum = $this->getDataGenerator()->create_module('forum', array('course' => $course->id));
+        $context = context_module::instance($forum->cmid);
+
+        /* @var mod_forum_generator $forumgenerator */
+        $forumgenerator = $this->getDataGenerator()->get_plugin_generator('mod_forum');
+        $discussion = $forumgenerator->create_discussion(
+            array(
+                'course' => $course->id,
+                'forum' => $forum->id,
+                'userid' => $user->id,
+                'attachment' => 1
+            )
+        );
+
+        $fs = get_file_storage();
+        $dummyone = (object) array(
+            'contextid' => $context->id,
+            'component' => 'mod_forum',
+            'filearea' => 'attachment',
+            'itemid' => $discussion->firstpost,
+            'filepath' => '/',
+            'filename' => 'myassignmnent.pdf'
+        );
+        $firstpostfile = $fs->create_file_from_string($dummyone, 'Content of ' . $dummyone->filename);
+
+        // Create a second post and add a file there.
+        $secondpost = $forumgenerator->create_post(
+            array(
+                'discussion' => $discussion->id,
+                'userid' => $user->id,
+                'attachment' => 1
+            )
+        );
+        $dummytwo = (object) array(
+            'contextid' => $context->id,
+            'component' => 'mod_forum',
+            'filearea' => 'attachment',
+            'itemid' => $secondpost->id,
+            'filepath' => '/',
+            'filename' => 'myotherthing.pdf'
+        );
+        $secondpostfile = $fs->create_file_from_string($dummytwo, 'Content of ' . $dummytwo->filename);
+
+        $caller = new forum_portfolio_caller(array(
+            'postid' => $discussion->firstpost,
+            'attachment' => $secondpostfile->get_id()
+        ));
+
+        $this->expectExceptionMessage('Sorry, the requested file could not be found');
+        $caller->load_data();
+    }
+}