test_save_backpack_credentials PHPUnit test sample

    /**
     * Test to validate badges_save_backpack_credentials.
     *
     * @dataProvider save_backpack_credentials_provider
     * @param  bool $addbackpack True if backpack data has to be created; false otherwise (empty data will be used then).
     * @param  string|null  $mail  Backpack mail address.
     * @param  string|null  $password  Backpack password.
     */
    public function test_save_backpack_credentials(bool $addbackpack = true, ?string $mail = null, ?string $password = null) {
        global $DB;

        $this->resetAfterTest();
        $this->setAdminUser();

        $data = [];
        if ($addbackpack) {
            $data = new \stdClass();
            $data->apiversion = OPEN_BADGES_V2P1;
            $data->backpackapiurl = 'https://dc.imsglobal.org/obchost/ims/ob/v2p1';
            $data->backpackweburl = 'https://dc.imsglobal.org';
            badges_create_site_backpack($data);
            $backpack = $DB->get_record('badge_external_backpack', ['backpackweburl' => $data->backpackweburl]);
            $user = $this->getDataGenerator()->create_user();

            $data = [
                'externalbackpackid' => $backpack->id,
                'userid' => $user->id,
            ];

            if (!empty($mail)) {
                $data['backpackemail'] = $mail;
            }
            if (!empty($password)) {
                $data['password'] = $password;
            }
        }

        $return = badges_save_backpack_credentials((object) $data);
        if (array_key_exists('userid', $data)) {
            $record = $DB->get_record('badge_backpack', ['userid' => $user->id]);
        } else {
            $record = $DB->get_records('badge_backpack');
        }

        if (!empty($mail) && !empty($password)) {
            // The backpack credentials are created if the given information is right.
            $this->assertNotEmpty($record);
            $this->assertEquals($data['externalbackpackid'], $return);
        } else if ($addbackpack) {
            // If no email and password are given, no backpack is created/modified.
            $this->assertEmpty($record);
            $this->assertEquals($data['externalbackpackid'], $return);
        } else {
            // There weren't fields to add to the backpack so no DB change is expected.
            $this->assertEmpty($record);
            $this->assertEquals(0, $return);
        }

        // Confirm the existing backpack credential can be updated (if it has been created).
        if (!empty($record)) {
            $data['backpackemail'] = 'modified_' . $mail;
            $data['id'] = $record->id;
            $return = badges_save_backpack_credentials((object) $data);
            $record = $DB->get_record('badge_backpack', ['userid' => $user->id]);

            $this->assertNotEmpty($record);
            $this->assertEquals($data['backpackemail'], $record->email);
            $this->assertEquals($data['externalbackpackid'], $return);
        }
    }

    /**
     * Data provider for test_create_backpack_credentials().
     *
     * @return array
     */
    public function save_backpack_credentials_provider(): array {
        return [
            'Empty fields' => [
                false,
            ],
            'No backpack mail or password are defined' => [
                true,
            ],
            'Both backpack mail and password are defined' => [
                true, 'test@test.com', '1234',
            ],
            'Only backpack mail is defined (no password is given)' => [
                true, 'test@test.com', null,
            ],
            'Only backpack password is defined (no mail is given)' => [
                true, null, '1234'
            ],
        ];
    }