diff --git a/completion/tests/generator/behat_core_completion_generator.php b/completion/tests/generator/behat_core_completion_generator.php
new file mode 100644
index 00000000000..903817bafa6
--- /dev/null
+++ b/completion/tests/generator/behat_core_completion_generator.php
@@ -0,0 +1,59 @@
+<?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/>.
+
+/**
+ * Completion test generator for Behat
+ *
+ * @package     core_completion
+ * @copyright   2023 Amaia Anabitarte <amaia@moodle.com>
+ * @license     http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class behat_core_completion_generator extends behat_generator_base {
+
+    /**
+     * Get a list of the entities that can be created for completion
+     *
+     * @return array[]
+     */
+    protected function get_creatable_entities(): array {
+        return [
+            'Course defaults' => [
+                'singular' => 'Course default',
+                'datagenerator' => 'default_completion',
+                'required' => [
+                    'course',
+                    'module',
+                ],
+                'switchids' => [
+                    'course' => 'course',
+                    'module' => 'module',
+                ],
+            ],
+        ];
+    }
+
+    /**
+     * Look up module ID from given name
+     *
+     * @param string $name
+     * @return int
+     */
+    protected function get_module_id(string $name): int {
+        global $DB;
+
+        return (int) $DB->get_field('modules', 'id', ['name' => $name], MUST_EXIST);
+    }
+}
diff --git a/completion/tests/generator/lib.php b/completion/tests/generator/lib.php
new file mode 100644
index 00000000000..2b661704403
--- /dev/null
+++ b/completion/tests/generator/lib.php
@@ -0,0 +1,63 @@
+<?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/>.
+
+/**
+ * Completion test generator
+ *
+ * @package     core_completion
+ * @copyright   2023 Amaia Anabitarte <amaia@moodle.com>
+ * @license     http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class core_completion_generator extends component_generator_base {
+
+    /**
+     * Create default completion
+     *
+     * @param array|stdClass $record
+     * @return stdClass
+     */
+    public function create_default_completion($record): stdClass {
+        global $DB;
+
+        $record = (array) $record;
+
+        if (!array_key_exists('course', $record) || !is_numeric($record['course'])) {
+            throw new moodle_exception('courserequired');
+        }
+        if (!$DB->get_record('course', ['id' => $record['course']])) {
+            throw new moodle_exception('invalidcourseid');
+        }
+
+        if (!array_key_exists('module', $record) || !is_numeric($record['module'])) {
+            throw new moodle_exception('modulerequired');
+        }
+        if (!$DB->get_record('modules', ['id' => $record['module']])) {
+            throw new moodle_exception('invalidmoduleid');
+        }
+
+        $record = (object) array_merge([
+            'completion' => 0,
+            'completionview' => 0,
+            'completionusegrade' => 0,
+            'completionpassgrade' => 0,
+            'completionexpected' => 0,
+            'customrules' => '',
+        ], $record);
+        $record->id = $DB->insert_record('course_completion_defaults', $record);
+
+        return $record;
+    }
+}
diff --git a/completion/tests/generator_test.php b/completion/tests/generator_test.php
new file mode 100644
index 00000000000..7c5f6826bcc
--- /dev/null
+++ b/completion/tests/generator_test.php
@@ -0,0 +1,138 @@
+<?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 core_completion;
+
+/**
+ * PHPUnit data generator testcase
+ *
+ * @package     core_completion
+ * @category    test
+ * @copyright   2023 Amaia Anabitarte <amaia@moodle.com>
+ * @license     http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ * @coversDefaultClass \core_completion_generator
+ */
+class generator_test extends \advanced_testcase {
+
+    /**
+     * Test create_default_completion.
+     *
+     * @dataProvider create_default_completion_provider
+     *
+     * @param int|null|string $course The course to add the default activities conditions to.
+     * @param int|null|string $module The module to add the default activities conditions to.
+     * @param bool $exception Whether an exception is expected or not.
+     * @param int $count The number of default activity completions to be created.
+     * @param int $completion The value for completion setting.
+     *
+     * @covers ::create_default_completion
+     */
+    public function test_create_default_completion($course, $module, bool $exception, int $count, int $completion = 0) {
+        global $DB;
+
+        $this->resetAfterTest(true);
+        $generator = $this->getDataGenerator()->get_plugin_generator('core_completion');
+
+        $record = [
+            'course' => $course,
+            'module' => $module,
+            'completion' => $completion,
+        ];
+        $result = (object) array_merge([
+            'completion' => 0,
+            'completionview' => 0,
+            'completionusegrade' => 0,
+            'completionpassgrade' => 0,
+            'completionexpected' => 0,
+            'customrules' => '',
+        ], $record);
+
+        if ($exception) {
+            $this->expectException('moodle_exception');
+        }
+        $defaultcompletion = $generator->create_default_completion($record);
+
+        if (!$exception) {
+            foreach ($result as $key => $value) {
+                $this->assertEquals($defaultcompletion->{$key}, $value);
+            }
+        }
+        $this->assertEquals(
+            $count,
+            $DB->count_records('course_completion_defaults', ['course' => $course, 'module' => $module])
+        );
+    }
+
+    /**
+     * Data provider for test_create_default_completion().
+     * @return array[]
+     */
+    public function create_default_completion_provider(): array {
+        global $SITE;
+
+        return [
+            'Null course' => [
+                'course' => null,
+                'module' => null,
+                'exception' => true,
+                'count' => 0,
+            ],
+            'Empty course' => [
+                'course' => '',
+                'module' => null,
+                'exception' => true,
+                'count' => 0,
+            ],
+            'Invalid course' => [
+                'course' => 0,
+                'module' => null,
+                'exception' => true,
+                'count' => 0,
+            ],
+            'Null module' => [
+                'course' => $SITE->id,
+                'module' => null,
+                'exception' => true,
+                'count' => 0,
+            ],
+            'Empty module' => [
+                'course' => $SITE->id,
+                'module' => null,
+                'exception' => true,
+                'count' => 0,
+            ],
+            'Invalid module' => [
+                'course' => $SITE->id,
+                'module' => 0,
+                'exception' => true,
+                'count' => 0,
+            ],
+            'Default activity completion: NONE' => [
+                'course' => $SITE->id,
+                'module' => 1,
+                'exception' => false,
+                'count' => 1,
+            ],
+            'Default activity completion: AUTOMATIC' => [
+                'course' => $SITE->id,
+                'module' => 1,
+                'exception' => false,
+                'count' => 1,
+                'completion' => 2,
+            ],
+        ];
+    }
+}
diff --git a/lib/testing/tests/testing_generator_test.php b/lib/testing/tests/testing_generator_test.php
index 0291121d49b..46ae0f9e926 100644
--- a/lib/testing/tests/testing_generator_test.php
+++ b/lib/testing/tests/testing_generator_test.php
@@ -47,8 +47,8 @@ class testing_generator_test extends \advanced_testcase {
      */
     public function test_get_plugin_generator_no_component_dir() {
         $this->expectException(\coding_exception::class);
-        $this->expectExceptionMessage('Component core_completion does not support generators yet. Missing tests/generator/lib.php.');
-        $generator = $this->getDataGenerator()->get_plugin_generator('core_completion');
+        $this->expectExceptionMessage('Component core_cohort does not support generators yet. Missing tests/generator/lib.php.');
+        $generator = $this->getDataGenerator()->get_plugin_generator('core_cohort');
     }
 
     public function test_create_user() {