MDL-81522 phpunit: Add missing void return type to all tests

While this change is not 100% required now, it's good habit
and we are checking for it since Moodle 4.4.

All the changes in this commit have been applied automatically
using the moodle.PHPUnit.TestReturnType sniff and are, exclusively
adding the ": void" return types when missing.

lib/tests/context/system_test.php

@@ -33,7 +33,7 @@ class system_test extends \advanced_testcase {
      * Tests legacy class.
      * @coversNothing
      */
-    public function test_legacy_classname() {
+    public function test_legacy_classname(): void {
         $context = \context_system::instance();
         $this->assertInstanceOf(system::class, $context);
         $this->assertInstanceOf(\context_system::class, $context);
@@ -44,7 +44,7 @@ class system_test extends \advanced_testcase {
      * @covers ::instance
      * @covers \core\context::instance_by_id
      */
-    public function test_factory_methods() {
+    public function test_factory_methods(): void {
         $context = system::instance();
         $this->assertInstanceOf(system::class, $context);
         $this->assertEquals(SYSCONTEXTID, $context->id);
@@ -58,7 +58,7 @@ class system_test extends \advanced_testcase {
      * Tests covered method.
      * @covers ::get_short_name
      */
-    public function test_get_short_name() {
+    public function test_get_short_name(): void {
         $this->assertSame('system', system::get_short_name());
     }
 
@@ -66,7 +66,7 @@ class system_test extends \advanced_testcase {
      * Tests context level.
      * @coversNothing
      */
-    public function test_level() {
+    public function test_level(): void {
         $this->assertSame(10, system::LEVEL);
         $this->assertSame(CONTEXT_SYSTEM, system::LEVEL);
     }
@@ -75,7 +75,7 @@ class system_test extends \advanced_testcase {
      * Tests covered method.
      * @covers ::get_level_name
      */
-    public function test_get_level_name() {
+    public function test_get_level_name(): void {
         $this->assertSame('System', system::get_level_name());
     }
 
@@ -83,7 +83,7 @@ class system_test extends \advanced_testcase {
      * Tests covered method.
      * @covers ::get_context_name
      */
-    public function test_get_context_name() {
+    public function test_get_context_name(): void {
         $context = system::instance();
         $this->assertSame('System', $context->get_context_name());
         $this->assertSame('System', $context->get_context_name(true));
@@ -96,7 +96,7 @@ class system_test extends \advanced_testcase {
      * Tests covered method.
      * @covers ::get_url
      */
-    public function test_get_url() {
+    public function test_get_url(): void {
         $context = system::instance();
         $expected = new \moodle_url('/');
         $url = $context->get_url();
@@ -108,7 +108,7 @@ class system_test extends \advanced_testcase {
      * Tests covered method.
      * @covers \core\context_helper::resolve_behat_reference
      */
-    public function test_resolve_behat_reference() {
+    public function test_resolve_behat_reference(): void {
         $syscontext = context\system::instance();
 
         $result = context_helper::resolve_behat_reference('System', '');
@@ -128,7 +128,7 @@ class system_test extends \advanced_testcase {
      * Tests covered method.
      * @covers ::get_compatible_role_archetypes
      */
-    public function test_get_compatible_role_archetypes() {
+    public function test_get_compatible_role_archetypes(): void {
         global $DB;
 
         $allarchetypes = $DB->get_fieldset_select('role', 'DISTINCT archetype', 'archetype IS NOT NULL');
@@ -146,7 +146,7 @@ class system_test extends \advanced_testcase {
      * Tests covered method.
      * @covers ::get_possible_parent_levels
      */
-    public function test_get_possible_parent_levels() {
+    public function test_get_possible_parent_levels(): void {
         $this->assertSame([], system::get_possible_parent_levels());
     }
 
@@ -154,7 +154,7 @@ class system_test extends \advanced_testcase {
      * Tests covered method.
      * @covers ::get_capabilities
      */
-    public function test_get_capabilities() {
+    public function test_get_capabilities(): void {
         global $DB;
 
         $context = system::instance();
@@ -167,7 +167,7 @@ class system_test extends \advanced_testcase {
      * Tests covered method.
      * @covers ::create_level_instances
      */
-    public function test_create_level_instances() {
+    public function test_create_level_instances(): void {
         context_helper::create_instances(system::LEVEL);
     }
 
@@ -175,7 +175,7 @@ class system_test extends \advanced_testcase {
      * Tests covered method.
      * @covers ::get_child_contexts
      */
-    public function test_get_child_contexts() {
+    public function test_get_child_contexts(): void {
         global $DB;
 
         $context = system::instance();
@@ -190,7 +190,7 @@ class system_test extends \advanced_testcase {
      * Tests covered method.
      * @covers ::get_cleanup_sql
      */
-    public function test_get_cleanup_sql() {
+    public function test_get_cleanup_sql(): void {
         // Nothing to clean up actually.
         context_helper::cleanup_instances();
     }
@@ -199,7 +199,7 @@ class system_test extends \advanced_testcase {
      * Tests covered method.
      * @covers ::build_paths
      */
-    public function test_build_paths() {
+    public function test_build_paths(): void {
         global $DB;
         $this->resetAfterTest();
 
@@ -217,7 +217,7 @@ class system_test extends \advanced_testcase {
      * Tests covered method.
      * @covers ::set_locked
      */
-    public function test_set_locked() {
+    public function test_set_locked(): void {
         $context = system::instance();
 
         $context->set_locked(false);