diff --git a/tests/Cms/Api/ApiTest.php b/tests/Cms/Api/ApiTest.php
index 75263425d2..16ecfa019f 100644
--- a/tests/Cms/Api/ApiTest.php
+++ b/tests/Cms/Api/ApiTest.php
@@ -52,16 +52,12 @@ public function setUp(): void
 			'options' => [
 				'api' => [
 					'allowImpersonation' => true,
-					'authentication' => function () {
-						return true;
-					},
-					'routes' => [
+					'authentication'     => fn () => true,
+					'routes'             => [
 						[
 							'pattern' => 'foo',
 							'method'  => 'GET',
-							'action'  => function () {
-								return 'something';
-							}
+							'action'  => fn () => 'something'
 						]
 					]
 				],
@@ -664,18 +660,14 @@ public function testSectionApi()
 		$app = $this->app->clone([
 			'sections' => [
 				'test' => [
-					'api' => function () {
-						return [
-							[
-								'pattern' => '/message',
-								'action'  => function () {
-									return [
-										'message' => 'Test'
-									];
-								}
+					'api' => fn () => [
+						[
+							'pattern' => '/message',
+							'action'  => fn () => [
+								'message' => 'Test'
 							]
-						];
-					}
+						]
+					]
 				]
 			],
 			'blueprints' => [
diff --git a/tests/Cms/Api/routes/AccountRoutesTest.php b/tests/Cms/Api/routes/AccountRoutesTest.php
index 14d2a720b9..bb659087b2 100644
--- a/tests/Cms/Api/routes/AccountRoutesTest.php
+++ b/tests/Cms/Api/routes/AccountRoutesTest.php
@@ -218,22 +218,16 @@ public function testFields()
 			],
 			'fields' => [
 				'test' => [
-					'api' => function () {
-						return [
-							[
-								'pattern' => '/',
-								'action'  => function () {
-									return 'Test home route';
-								}
-							],
-							[
-								'pattern' => 'nested',
-								'action'  => function () {
-									return 'Test nested route';
-								}
-							],
-						];
-					}
+					'api' => fn () => [
+						[
+							'pattern' => '/',
+							'action'  => fn () => 'Test home route'
+						],
+						[
+							'pattern' => 'nested',
+							'action'  => fn () => 'Test nested route'
+						],
+					]
 				]
 			]
 		]);
@@ -371,11 +365,9 @@ public function testSections()
 			],
 			'sections' => [
 				'test' => [
-					'toArray' => function () {
-						return [
-							'foo' => 'bar'
-						];
-					}
+					'toArray' => fn () => [
+						'foo' => 'bar'
+					]
 				]
 			]
 		]);
diff --git a/tests/Cms/Api/routes/UsersRoutesTest.php b/tests/Cms/Api/routes/UsersRoutesTest.php
index e16469ae10..2fde03dade 100644
--- a/tests/Cms/Api/routes/UsersRoutesTest.php
+++ b/tests/Cms/Api/routes/UsersRoutesTest.php
@@ -237,22 +237,16 @@ public function testFields()
 			],
 			'fields' => [
 				'test' => [
-					'api' => function () {
-						return [
-							[
-								'pattern' => '/',
-								'action'  => function () {
-									return 'Test home route';
-								}
-							],
-							[
-								'pattern' => 'nested',
-								'action'  => function () {
-									return 'Test nested route';
-								}
-							],
-						];
-					}
+					'api' => fn () => [
+						[
+							'pattern' => '/',
+							'action'  => fn () => 'Test home route'
+						],
+						[
+							'pattern' => 'nested',
+							'action'  => fn () => 'Test nested route'
+						],
+					]
 				]
 			]
 		]);
@@ -431,11 +425,9 @@ public function testSections()
 			],
 			'sections' => [
 				'test' => [
-					'toArray' => function () {
-						return [
-							'foo' => 'bar'
-						];
-					}
+					'toArray' => fn () => [
+						'foo' => 'bar'
+					]
 				]
 			]
 		]);
diff --git a/tests/Cms/App/AppComponentsTest.php b/tests/Cms/App/AppComponentsTest.php
index 53c9a2a8c5..97cb2bab4b 100644
--- a/tests/Cms/App/AppComponentsTest.php
+++ b/tests/Cms/App/AppComponentsTest.php
@@ -44,9 +44,7 @@ public function testCssPlugin()
 	{
 		$this->kirby->clone([
 			'components' => [
-				'css' => function ($kirby, $url, $options) {
-					return '/test.css';
-				}
+				'css' => fn ($kirby, $url, $options) => '/test.css'
 			]
 		]);
 
@@ -58,9 +56,7 @@ public function testJsPlugin()
 	{
 		$this->kirby->clone([
 			'components' => [
-				'js' => function ($kirby, $url, $options) {
-					return '/test.js';
-				}
+				'js' => fn ($kirby, $url, $options) => '/test.js'
 			]
 		]);
 
@@ -361,9 +357,7 @@ public function testUrlPlugin()
 	{
 		$this->kirby->clone([
 			'components' => [
-				'url' => function ($kirby, $path, $options) {
-					return 'test';
-				}
+				'url' => fn ($kirby, $path, $options) => 'test'
 			]
 		]);
 
diff --git a/tests/Cms/App/AppPluginsTest.php b/tests/Cms/App/AppPluginsTest.php
index 1fff1302f6..99c90c05ad 100644
--- a/tests/Cms/App/AppPluginsTest.php
+++ b/tests/Cms/App/AppPluginsTest.php
@@ -67,14 +67,10 @@ public function testApi()
 				'routes' => [
 					[
 						'pattern' => 'awesome',
-						'action'  => function () {
-							return 'nice';
-						}
+						'action'  => fn () => 'nice'
 					]
 				],
-				'authentication' => function () {
-					return true;
-				}
+				'authentication' => fn () => true
 			]
 		]);
 
@@ -89,9 +85,7 @@ public function testApiRoutePlugins()
 				'routes' => [
 					[
 						'pattern' => 'a',
-						'action'  => function () {
-							return 'a';
-						}
+						'action'  => fn () => 'a'
 					]
 				]
 			]
@@ -102,9 +96,7 @@ public function testApiRoutePlugins()
 				'routes' => [
 					[
 						'pattern' => 'b',
-						'action'  => function () {
-							return 'b';
-						}
+						'action'  => fn () => 'b'
 					]
 				]
 			]
@@ -115,9 +107,7 @@ public function testApiRoutePlugins()
 				'routes' => [
 					[
 						'pattern' => 'c',
-						'action'  => function () {
-							return 'c';
-						}
+						'action'  => fn () => 'c'
 					]
 				]
 			]
@@ -128,9 +118,7 @@ public function testApiRoutePlugins()
 				'index' => '/dev/null'
 			],
 			'api' => [
-				'authentication' => function () {
-					return true;
-				}
+				'authentication' => fn () => true
 			],
 		]);
 
@@ -145,31 +133,23 @@ public function testApiRouteCallbackPlugins()
 	{
 		App::plugin('test/a', [
 			'api' => [
-				'routes' => function ($kirby) {
-					return [
-						[
-							'pattern' => 'a',
-							'action'  => function () use ($kirby) {
-								return $kirby->root('index');
-							}
-						]
-					];
-				}
+				'routes' => fn ($kirby) => [
+					[
+						'pattern' => 'a',
+						'action'  => fn () => $kirby->root('index')
+					]
+				]
 			]
 		]);
 
 		App::plugin('test/b', [
 			'api' => [
-				'routes' => function ($kirby) {
-					return [
-						[
-							'pattern' => 'b',
-							'action'  => function () {
-								return 'b';
-							}
-						]
-					];
-				}
+				'routes' => fn ($kirby) => [
+					[
+						'pattern' => 'b',
+						'action'  => fn () => 'b'
+					]
+				]
 			]
 		]);
 
@@ -178,9 +158,7 @@ public function testApiRouteCallbackPlugins()
 				'routes' => [
 					[
 						'pattern' => 'c',
-						'action'  => function () {
-							return 'c';
-						}
+						'action'  => fn () => 'c'
 					]
 				]
 			]
@@ -191,9 +169,7 @@ public function testApiRouteCallbackPlugins()
 				'index' => '/dev/null'
 			],
 			'api' => [
-				'authentication' => function () {
-					return true;
-				}
+				'authentication' => fn () => true
 			],
 		]);
 
@@ -211,16 +187,12 @@ public function testApiRouteCallbackPluginWithOptionAccess()
 				'test' => 'Test'
 			],
 			'api' => [
-				'routes' => function ($kirby) {
-					return [
-						[
-							'pattern' => 'test',
-							'action'  => function () use ($kirby) {
-								return $kirby->option('your.plugin.test');
-							}
-						]
-					];
-				}
+				'routes' => fn ($kirby) => [
+					[
+						'pattern' => 'test',
+						'action'  => fn () => $kirby->option('your.plugin.test')
+					]
+				]
 			]
 		]);
 
@@ -342,9 +314,7 @@ public function testCollectionFilters()
 			],
 			'collectionFilters' => [
 				'**' => $filter = [
-					'validator' => function ($value, $test) {
-						return $value === 'foo';
-					}
+					'validator' => fn ($value, $test) => $value === 'foo'
 				]
 			]
 		]);
@@ -380,9 +350,7 @@ public function testController()
 				'index' => '/dev/null'
 			],
 			'controllers' => [
-				'test' => function () {
-					return ['foo' => 'bar'];
-				}
+				'test' => fn () => ['foo' => 'bar']
 			]
 		]);
 
@@ -396,9 +364,7 @@ public function testFieldMethod()
 				'index' => '/dev/null'
 			],
 			'fieldMethods' => [
-				'test' => function () {
-					return 'test';
-				}
+				'test' => fn () => 'test'
 			]
 		]);
 
@@ -440,14 +406,10 @@ public function testKirbyTag()
 			],
 			'tags' => [
 				'test' => [
-					'html' => function () {
-						return 'test';
-					}
+					'html' => fn () => 'test'
 				],
 				'FoO' => [
-					'html' => function () {
-						return 'test';
-					}
+					'html' => fn () => 'test'
 				]
 			]
 		]);
@@ -466,9 +428,7 @@ public function testPageMethod()
 				'index' => '/dev/null'
 			],
 			'pageMethods' => [
-				'test' => function () {
-					return 'test';
-				}
+				'test' => fn () => 'test'
 			]
 		]);
 
@@ -486,9 +446,7 @@ public function testPagesMethod()
 				'index' => '/dev/null'
 			],
 			'pagesMethods' => [
-				'test' => function () {
-					return 'test';
-				}
+				'test' => fn () => 'test'
 			]
 		]);
 
@@ -731,9 +689,7 @@ public function testRoutes()
 			'routes' => [
 				[
 					'pattern' => 'test',
-					'action'  => function () {
-						return 'test';
-					}
+					'action'  => fn () => 'test'
 				]
 			]
 		]);
@@ -747,16 +703,12 @@ public function testRoutesCallback()
 			'roots' => [
 				'index' => '/dev/null'
 			],
-			'routes' => function () {
-				return [
-					[
-						'pattern' => 'test',
-						'action'  => function () {
-							return 'test';
-						}
-					]
-				];
-			}
+			'routes' => fn () => [
+				[
+					'pattern' => 'test',
+					'action'  => fn () => 'test'
+				]
+			]
 		]);
 
 		$this->assertSame('test', $kirby->call('test'));
@@ -850,9 +802,7 @@ public function testUserMethod()
 				'index' => '/dev/null'
 			],
 			'userMethods' => [
-				'test' => function () {
-					return 'test';
-				}
+				'test' => fn () => 'test'
 			]
 		]);
 
@@ -892,9 +842,7 @@ public function testUsersMethod()
 				'index' => '/dev/null'
 			],
 			'usersMethods' => [
-				'test' => function () {
-					return 'test';
-				}
+				'test' => fn () => 'test'
 			]
 		]);
 
@@ -1031,9 +979,7 @@ public function testAreas()
 				'index' => '/dev/null'
 			],
 			'areas' => [
-				'todos' => function () {
-					return [];
-				}
+				'todos' => fn () => []
 			]
 		]);
 
diff --git a/tests/Cms/App/AppTest.php b/tests/Cms/App/AppTest.php
index a25b0218d7..52f3ef18a4 100644
--- a/tests/Cms/App/AppTest.php
+++ b/tests/Cms/App/AppTest.php
@@ -192,9 +192,7 @@ public function testCollection()
 				]
 			],
 			'collections' => [
-				'test' => function ($pages) {
-					return $pages;
-				}
+				'test' => fn ($pages) => $pages
 			]
 		]);
 
@@ -287,9 +285,7 @@ public function testContentToken()
 		// with callback
 		$app = new App([
 			'options' => [
-				'content.salt' => function ($model) {
-					return 'salt ' . $model;
-				}
+				'content.salt' => fn ($model) => 'salt ' . $model
 			]
 		]);
 		$this->assertSame(hash_hmac('sha1', 'test', 'salt lake city'), $app->contentToken('lake city', 'test'));
@@ -719,16 +715,14 @@ public function testOptionsOnReady()
 				]
 			],
 			'options' => [
-				'ready' => $ready = function ($kirby) {
-					return [
-						'test'         => $kirby->root('index'),
-						'another.test' => 'foo',
-						'debug'        => true,
-						'home'         => $kirby->site()->content()->home()->value(),
-						'error'        => $kirby->site()->content()->error()->value(),
-						'slugs'        => 'de'
-					];
-				},
+				'ready' => $ready = fn ($kirby) => [
+					'test'         => $kirby->root('index'),
+					'another.test' => 'foo',
+					'debug'        => true,
+					'home'         => $kirby->site()->content()->home()->value(),
+					'error'        => $kirby->site()->content()->error()->value(),
+					'slugs'        => 'de'
+				],
 				'whoops' => true
 			]
 		]);
@@ -1332,9 +1326,8 @@ public function testControllerCallback()
 				'index' => '/dev/null'
 			],
 			'controllers' => [
-				'test' => function () {
-					return ['foo' => 'bar'];
-				}
+				'test' => fn () => ['foo' => 'bar']
+
 			]
 		]);
 
diff --git a/tests/Cms/Blocks/BlocksMethodsTest.php b/tests/Cms/Blocks/BlocksMethodsTest.php
index da48117798..e1e949da61 100644
--- a/tests/Cms/Blocks/BlocksMethodsTest.php
+++ b/tests/Cms/Blocks/BlocksMethodsTest.php
@@ -15,9 +15,7 @@ public function setUp(): void
 				'index' => '/dev/null',
 			],
 			'blocksMethods' => [
-				'test' => function () {
-					return 'blocks method';
-				}
+				'test' => fn () => 'blocks method'
 			]
 		]);
 	}
diff --git a/tests/Cms/Blueprints/BlueprintTest.php b/tests/Cms/Blueprints/BlueprintTest.php
index 5c0f9509ad..bb392a67fa 100644
--- a/tests/Cms/Blueprints/BlueprintTest.php
+++ b/tests/Cms/Blueprints/BlueprintTest.php
@@ -649,9 +649,7 @@ public function testFactoryWithCallbackArray()
 
 		$this->app = $this->app->clone([
 			'blueprints' => [
-				'pages/test' => function () {
-					return ['title' => 'Test'];
-				}
+				'pages/test' => fn () => ['title' => 'Test']
 			]
 		]);
 
@@ -675,9 +673,7 @@ public function testFactoryWithCallbackString()
 				'blueprints' => static::TMP,
 			],
 			'blueprints' => [
-				'pages/test' => function () {
-					return static::TMP . '/custom/test.yml';
-				}
+				'pages/test' => fn () => static::TMP . '/custom/test.yml'
 			]
 		]);
 
diff --git a/tests/Cms/Collections/CollectionTest.php b/tests/Cms/Collections/CollectionTest.php
index 1a2c3abc34..a95672c565 100644
--- a/tests/Cms/Collections/CollectionTest.php
+++ b/tests/Cms/Collections/CollectionTest.php
@@ -47,9 +47,7 @@ public function testCollectionMethods()
 	{
 		$kirby = $this->kirby([
 			'collectionMethods' => [
-				'test' => function () {
-					return 'collection test';
-				}
+				'test' => fn () => 'collection test'
 			],
 			'roots' => [
 				'index' => '/dev/null'
@@ -502,9 +500,7 @@ public function testToArrayWithCallback()
 			new MockObject(['id' => 'c'])
 		]);
 
-		$array = $collection->toArray(function ($object) {
-			return $object->id();
-		});
+		$array = $collection->toArray(fn ($object) => $object->id());
 
 		$this->assertSame($array, [
 			'a' => 'a',
diff --git a/tests/Cms/KirbyTextTest.php b/tests/Cms/KirbyTextTest.php
index f80a38b77c..c25b585949 100644
--- a/tests/Cms/KirbyTextTest.php
+++ b/tests/Cms/KirbyTextTest.php
@@ -13,9 +13,7 @@ public function testBeforeHook()
 				'index' => '/dev/null'
 			],
 			'hooks' => [
-				'kirbytext:before' => function ($text) {
-					return strtolower($text);
-				}
+				'kirbytext:before' => fn ($text) => strtolower($text)
 			]
 		]);
 
@@ -31,9 +29,7 @@ public function testAfterHook()
 				'index' => '/dev/null'
 			],
 			'hooks' => [
-				'kirbytext:after' => function ($text) {
-					return strip_tags($text);
-				}
+				'kirbytext:after' => fn ($text) => strip_tags($text)
 			]
 		]);
 
diff --git a/tests/Cms/Languages/LanguageRouterTest.php b/tests/Cms/Languages/LanguageRouterTest.php
index 35242d76c1..0916899e8f 100644
--- a/tests/Cms/Languages/LanguageRouterTest.php
+++ b/tests/Cms/Languages/LanguageRouterTest.php
@@ -32,16 +32,12 @@ public function testRouteForSingleLanguage()
 				[
 					'pattern'  => '(:any)',
 					'language' => 'en',
-					'action'   => function (Language $langauge, $slug) {
-						return 'en';
-					}
+					'action'   => fn (Language $langauge, $slug) => 'en'
 				],
 				[
 					'pattern'  => '(:any)',
 					'language' => 'de',
-					'action'   => function (Language $langauge, $slug) {
-						return 'de';
-					}
+					'action'   => fn (Language $langauge, $slug) => 'de'
 				]
 			]
 		]);
@@ -62,9 +58,7 @@ public function testRouteWithoutLanguageScope()
 			'routes' => [
 				[
 					'pattern'  => '(:any)',
-					'action'   => function ($slug) {
-						return $slug;
-					}
+					'action'   => fn ($slug) => $slug
 				]
 			]
 		]);
@@ -81,9 +75,7 @@ public function testRouteForMultipleLanguages()
 				[
 					'pattern'  => '(:any)',
 					'language' => 'en|de',
-					'action'   => function (Language $language, $slug) {
-						return $slug;
-					}
+					'action'   => fn (Language $language, $slug) => $slug
 				]
 			]
 		]);
@@ -105,9 +97,7 @@ public function testRouteWildcard()
 				[
 					'pattern'  => '(:any)',
 					'language' => '*',
-					'action'   => function (Language $language, $slug) {
-						return $slug;
-					}
+					'action'   => fn (Language $language, $slug) => $slug
 				]
 			]
 		]);
@@ -135,9 +125,7 @@ public function testRouteWithPageScope()
 					'pattern'  => '(:any)',
 					'language' => '*',
 					'page'     => 'notes',
-					'action'   => function (Language $language, Page $page, $slug) {
-						return $slug;
-					}
+					'action'   => fn (Language $language, Page $page, $slug) => $slug
 				]
 			]
 		]);
@@ -164,9 +152,7 @@ public function testRouteWithPageScopeAndMultiplePatterns()
 					],
 					'language' => '*',
 					'page'     => 'notes',
-					'action'   => function (Language $language, Page $page, $slug) {
-						return $slug;
-					}
+					'action'   => fn (Language $language, Page $page, $slug) => $slug
 				]
 			]
 		]);
@@ -191,9 +177,7 @@ public function testRouteWithPageScopeAndInvalidPage()
 					'pattern'  => '(:any)',
 					'language' => '*',
 					'page'     => 'does-not-exist',
-					'action'   => function (Language $language, Page $page, $slug) {
-						return $slug;
-					}
+					'action'   => fn (Language $language, Page $page, $slug) => $slug
 				]
 			]
 		]);
diff --git a/tests/Cms/Layouts/LayoutColumnMethodsTest.php b/tests/Cms/Layouts/LayoutColumnMethodsTest.php
index 9423bc42e4..1251ae1ce9 100644
--- a/tests/Cms/Layouts/LayoutColumnMethodsTest.php
+++ b/tests/Cms/Layouts/LayoutColumnMethodsTest.php
@@ -15,9 +15,7 @@ public function setUp(): void
 				'index' => '/dev/null',
 			],
 			'layoutColumnMethods' => [
-				'test' => function () {
-					return 'layout column method';
-				}
+				'test' => fn () => 'layout column method'
 			]
 		]);
 	}
diff --git a/tests/Cms/Layouts/LayoutMethodsTest.php b/tests/Cms/Layouts/LayoutMethodsTest.php
index e88215ab46..1891a3fcbb 100644
--- a/tests/Cms/Layouts/LayoutMethodsTest.php
+++ b/tests/Cms/Layouts/LayoutMethodsTest.php
@@ -15,9 +15,7 @@ public function setUp(): void
 				'index' => '/dev/null',
 			],
 			'layoutMethods' => [
-				'test' => function () {
-					return 'layout method';
-				}
+				'test' => fn () => 'layout method'
 			]
 		]);
 	}
diff --git a/tests/Cms/Layouts/LayoutsMethodsTest.php b/tests/Cms/Layouts/LayoutsMethodsTest.php
index 497dfa7388..edbe0293e4 100644
--- a/tests/Cms/Layouts/LayoutsMethodsTest.php
+++ b/tests/Cms/Layouts/LayoutsMethodsTest.php
@@ -15,9 +15,7 @@ public function setUp(): void
 				'index' => '/dev/null',
 			],
 			'layoutsMethods' => [
-				'test' => function () {
-					return 'layouts method';
-				}
+				'test' => fn () => 'layouts method'
 			]
 		]);
 	}
diff --git a/tests/Cms/Loader/LoaderTest.php b/tests/Cms/Loader/LoaderTest.php
index 9c425aed4c..5b9b9718a8 100644
--- a/tests/Cms/Loader/LoaderTest.php
+++ b/tests/Cms/Loader/LoaderTest.php
@@ -76,9 +76,7 @@ public function testAreaDropdownPlugin()
 			'areas' => [
 				'site' => [
 					'dropdowns' => [
-						'page' => function () {
-							return 'foo';
-						}
+						'page' => fn () => 'foo'
 					]
 				]
 			]
diff --git a/tests/Cms/Pages/PageCacheTest.php b/tests/Cms/Pages/PageCacheTest.php
index 98dee9d192..805030b154 100644
--- a/tests/Cms/Pages/PageCacheTest.php
+++ b/tests/Cms/Pages/PageCacheTest.php
@@ -143,9 +143,7 @@ public function testIgnoreCallback()
 		$app = $this->app->clone([
 			'options' => [
 				'cache.pages' => [
-					'ignore' => function ($page) {
-						return $page->id() === 'default';
-					}
+					'ignore' => fn ($page) => $page->id() === 'default'
 				]
 			]
 		]);
diff --git a/tests/Cms/Pages/PageMethodsTest.php b/tests/Cms/Pages/PageMethodsTest.php
index 194b4b1275..1808577552 100644
--- a/tests/Cms/Pages/PageMethodsTest.php
+++ b/tests/Cms/Pages/PageMethodsTest.php
@@ -12,14 +12,10 @@ public function setUp(): void
 	{
 		$this->app = new App([
 			'pageMethods' => [
-				'test' => function () {
-					return 'page method';
-				}
+				'test' => fn () => 'page method'
 			],
 			'pagesMethods' => [
-				'test' => function () {
-					return 'pages method';
-				}
+				'test' => fn () => 'pages method'
 			],
 			'site' => [
 				'children' => [
diff --git a/tests/Cms/Pages/PageTest.php b/tests/Cms/Pages/PageTest.php
index 8000e20b37..6a540e7901 100644
--- a/tests/Cms/Pages/PageTest.php
+++ b/tests/Cms/Pages/PageTest.php
@@ -707,9 +707,7 @@ public function testTokenWithSaltCallback()
 			],
 			'options' => [
 				'content' => [
-					'salt' => function ($page) {
-						return $page->date();
-					}
+					'salt' => fn ($page) => $page->date()
 				]
 			]
 		]);
@@ -956,9 +954,7 @@ public function testApiUrl()
 	public function testPageMethods()
 	{
 		Page::$methods = [
-			'test' => function () {
-				return 'homer';
-			}
+			'test' => fn () => 'homer'
 		];
 
 		$page = new Page(['slug' => 'test']);
@@ -1033,9 +1029,7 @@ public function testController()
 					return compact('page');
 				},
 				// invalid return
-				'bar' => function ($page) {
-					return ['page' => 'string'];
-				}
+				'bar' => fn ($page) => ['page' => 'string']
 			]
 		]);
 
diff --git a/tests/Cms/Routes/RouterTest.php b/tests/Cms/Routes/RouterTest.php
index 0d254c2bec..78b8140121 100644
--- a/tests/Cms/Routes/RouterTest.php
+++ b/tests/Cms/Routes/RouterTest.php
@@ -313,9 +313,7 @@ public function testCustomRoute($pattern, $path)
 			'routes' => [
 				[
 					'pattern' => $pattern,
-					'action'  => function () {
-						return 'test';
-					}
+					'action'  => fn () => 'test'
 				]
 			]
 		]);
diff --git a/tests/Cms/Sections/SectionTest.php b/tests/Cms/Sections/SectionTest.php
index e50ce64e68..db116fd00a 100644
--- a/tests/Cms/Sections/SectionTest.php
+++ b/tests/Cms/Sections/SectionTest.php
@@ -46,9 +46,7 @@ public function testApi()
 		// return simple string
 		Section::$types = [
 			'test' => [
-				'api' => function () {
-					return 'Hello World';
-				}
+				'api' => fn () => 'Hello World'
 			]
 		];
 
@@ -75,12 +73,8 @@ public function testPropsDefaults()
 	{
 		Section::$types['test'] = [
 			'props' => [
-				'example' => function ($example = 'default') {
-					return $example;
-				},
-				'buttons' => function ($buttons = ['one', 'two']) {
-					return $buttons;
-				},
+				'example' => fn ($example = 'default') => $example,
+				'buttons' => fn ($buttons = ['one', 'two']) => $buttons
 			]
 		];
 
@@ -96,12 +90,8 @@ public function testToResponse()
 	{
 		Section::$types['test'] = [
 			'props' => [
-				'a' => function ($a) {
-					return $a;
-				},
-				'b' => function ($b) {
-					return $b;
-				}
+				'a' => fn ($a) => $a,
+				'b' => fn ($b) => $b
 			]
 		];
 
diff --git a/tests/Cms/Sections/mixins/LayoutMixinTest.php b/tests/Cms/Sections/mixins/LayoutMixinTest.php
index 9be7ccde0c..7a3785beec 100644
--- a/tests/Cms/Sections/mixins/LayoutMixinTest.php
+++ b/tests/Cms/Sections/mixins/LayoutMixinTest.php
@@ -21,13 +21,9 @@ public function setUp(): void
 
 		Section::$types['test'] = Section::$types['pages'] = [
 			'mixins' => ['layout'],
-			'props'  => $props = [
-				'info' => function (string|null $info = null) {
-					return $info;
-				},
-				'text' => function (string|null $text = null) {
-					return $text;
-				}
+			'props'  => [
+				'info' => fn (string|null $info = null) => $info,
+				'text' => fn (string|null $text = null) => $text
 			]
 		];
 	}
diff --git a/tests/Cms/Sections/mixins/MaxSectionMixinTest.php b/tests/Cms/Sections/mixins/MaxSectionMixinTest.php
index cae8bbae15..0c98ed4cb6 100644
--- a/tests/Cms/Sections/mixins/MaxSectionMixinTest.php
+++ b/tests/Cms/Sections/mixins/MaxSectionMixinTest.php
@@ -22,9 +22,7 @@ public function setUp(): void
 		Section::$types['test'] = [
 			'mixins'   => ['max'],
 			'computed' => [
-				'total' => function () {
-					return 10;
-				}
+				'total' => fn () => 10
 			]
 		];
 	}
diff --git a/tests/Cms/Sections/mixins/MinSectionMixinTest.php b/tests/Cms/Sections/mixins/MinSectionMixinTest.php
index dbb3b86c11..d6464eba73 100644
--- a/tests/Cms/Sections/mixins/MinSectionMixinTest.php
+++ b/tests/Cms/Sections/mixins/MinSectionMixinTest.php
@@ -22,9 +22,7 @@ public function setUp(): void
 		Section::$types['test'] = [
 			'mixins'   => ['min'],
 			'computed' => [
-				'total' => function () {
-					return 10;
-				}
+				'total' => fn () => 10
 			]
 		];
 	}
diff --git a/tests/Cms/Sections/mixins/SortMixinTest.php b/tests/Cms/Sections/mixins/SortMixinTest.php
index 682ff6c9de..d6eeb511d3 100644
--- a/tests/Cms/Sections/mixins/SortMixinTest.php
+++ b/tests/Cms/Sections/mixins/SortMixinTest.php
@@ -22,18 +22,14 @@ public function setUp(): void
 		Section::$types['test'] = [
 			'mixins' => ['sort'],
 			'props'  => [
-				'query' => function (string|null $query = null) {
-					return $query;
-				}
+				'query' => fn (string|null $query = null) => $query
 			]
 		];
 
 		Section::$types['pages'] = [
 			'mixins' => ['sort'],
 			'props'  => [
-				'status' => function (string|null $status = null) {
-					return $status;
-				},
+				'status' => fn (string|null $status = null) => $status
 			]
 		];
 	}
diff --git a/tests/Cms/Site/SiteMethodsTest.php b/tests/Cms/Site/SiteMethodsTest.php
index 7954cc170d..851be03406 100644
--- a/tests/Cms/Site/SiteMethodsTest.php
+++ b/tests/Cms/Site/SiteMethodsTest.php
@@ -12,9 +12,7 @@ public function setUp(): void
 	{
 		$this->app = new App([
 			'siteMethods' => [
-				'test' => function () {
-					return 'site method';
-				}
+				'test' => fn () => 'site method'
 			],
 			'site' => [
 				'children' => [
diff --git a/tests/Cms/Structures/StructureMethodsTest.php b/tests/Cms/Structures/StructureMethodsTest.php
index 3b27e2af7a..6c1ebaae8e 100644
--- a/tests/Cms/Structures/StructureMethodsTest.php
+++ b/tests/Cms/Structures/StructureMethodsTest.php
@@ -15,9 +15,7 @@ public function setUp(): void
 				'index' => '/dev/null',
 			],
 			'structureMethods' => [
-				'test' => function () {
-					return 'structure method';
-				}
+				'test' => fn () => 'structure method'
 			]
 		]);
 	}
diff --git a/tests/Cms/Structures/StructureObjectMethodsTest.php b/tests/Cms/Structures/StructureObjectMethodsTest.php
index e94aa9e061..8079ef9b1b 100644
--- a/tests/Cms/Structures/StructureObjectMethodsTest.php
+++ b/tests/Cms/Structures/StructureObjectMethodsTest.php
@@ -15,9 +15,7 @@ public function setUp(): void
 				'index' => '/dev/null',
 			],
 			'structureObjectMethods' => [
-				'test' => function () {
-					return 'structure object method';
-				}
+				'test' => fn () => 'structure object method'
 			]
 		]);
 	}
diff --git a/tests/Cms/Users/UserTest.php b/tests/Cms/Users/UserTest.php
index e57ed2382a..5fd7be1578 100644
--- a/tests/Cms/Users/UserTest.php
+++ b/tests/Cms/Users/UserTest.php
@@ -472,9 +472,7 @@ public function testQuery()
 	public function testUserMethods()
 	{
 		User::$methods = [
-			'test' => function () {
-				return 'homer';
-			}
+			'test' => fn () => 'homer'
 		];
 
 		$user = new User([
diff --git a/tests/Content/FieldTest.php b/tests/Content/FieldTest.php
index 6fcd6ba198..15ba6ddad7 100644
--- a/tests/Content/FieldTest.php
+++ b/tests/Content/FieldTest.php
@@ -118,9 +118,7 @@ public function testValueCallbackSetter()
 	{
 		$field = new Field(null, 'title', 'Title');
 		$this->assertSame('Title', $field->value());
-		$field = $field->value(function ($value) {
-			return 'Modified';
-		});
+		$field = $field->value(fn ($value) => 'Modified');
 		$this->assertSame('Modified', $field->value());
 	}
 
diff --git a/tests/Database/DbTest.php b/tests/Database/DbTest.php
index df9dc7af04..3f2230b922 100644
--- a/tests/Database/DbTest.php
+++ b/tests/Database/DbTest.php
@@ -145,9 +145,7 @@ public function testCallStatic()
 			'prefix'   => 'myprefix_'
 		]);
 
-		Db::$queries['test'] = function ($test) {
-			return $test . ' test';
-		};
+		Db::$queries['test'] = fn ($test) => $test . ' test';
 		$this->assertSame('This is a test', Db::test('This is a'));
 		unset(Db::$queries['test']);
 
diff --git a/tests/Database/QueryTest.php b/tests/Database/QueryTest.php
index 4a5eb4d456..28e36f8e9a 100644
--- a/tests/Database/QueryTest.php
+++ b/tests/Database/QueryTest.php
@@ -335,9 +335,7 @@ public function testFetch()
 			->table('users')
 			->where(['username' => 'john']);
 
-		$x = function ($row, $key) {
-			return $row['fname'] . ' ' . $row['lname'];
-		};
+		$x = fn ($row, $key) => $row['fname'] . ' ' . $row['lname'];
 
 		$this->assertSame('John Lennon', (clone $query)->fetch($x)->first());
 		$this->assertSame('John Lennon', (clone $query)->fetch([$this, 'fetchTestCallable'])->first());
diff --git a/tests/Email/EmailTest.php b/tests/Email/EmailTest.php
index 373d33ea27..0f02323986 100644
--- a/tests/Email/EmailTest.php
+++ b/tests/Email/EmailTest.php
@@ -206,9 +206,7 @@ public function testBeforeSend()
 		// invalid
 		$mail = $this->_email([
 			'transport'  => $transport,
-			'beforeSend' => $beforeSend = function ($mailer) {
-				return 'string';
-			}
+			'beforeSend' => $beforeSend = fn ($mailer) => 'string'
 		], PHPMailer::class);
 
 		$this->expectException(InvalidArgumentException::class);
diff --git a/tests/Filesystem/AssetTest.php b/tests/Filesystem/AssetTest.php
index f574afe189..6d91f679df 100644
--- a/tests/Filesystem/AssetTest.php
+++ b/tests/Filesystem/AssetTest.php
@@ -23,9 +23,7 @@ public function setUp(): void
 				'index' => 'https://getkirby.com'
 			],
 			'assetMethods' => [
-				'test' => function () {
-					return 'asset method';
-				}
+				'test' => fn () => 'asset method'
 			]
 		]);
 	}
diff --git a/tests/Form/FieldTest.php b/tests/Form/FieldTest.php
index 6a2cdc616f..c3f235eb36 100644
--- a/tests/Form/FieldTest.php
+++ b/tests/Form/FieldTest.php
@@ -235,9 +235,7 @@ public function testDialogs()
 		// return routes
 		Field::$types = [
 			'test' => [
-				'dialogs' => function () use ($routes) {
-					return $routes;
-				}
+				'dialogs' => fn () => $routes
 			]
 		];
 
@@ -360,9 +358,7 @@ public function testIcon()
 		Field::$types = [
 			'test' => [
 				'props' => [
-					'icon' => function (string $icon = 'test') {
-						return $icon;
-					}
+					'icon' => fn (string $icon = 'test') => $icon
 				]
 			]
 		];
@@ -411,9 +407,7 @@ public function testIsEmptyWithCustomFunction()
 	{
 		Field::$types = [
 			'test' => [
-				'isEmpty' => function ($value) {
-					return $value === 0;
-				}
+				'isEmpty' => fn ($value) => $value === 0
 			]
 		];
 
@@ -675,13 +669,9 @@ public function testSaveHandler()
 		Field::$types = [
 			'test' => [
 				'props' => [
-					'value' => function ($value) {
-						return $value;
-					}
+					'value' => fn ($value) => $value
 				],
-				'save' => function ($value) {
-					return implode(', ', $value);
-				}
+				'save' => fn ($value) => implode(', ', $value)
 			]
 		];
 
@@ -700,9 +690,7 @@ public function testToArray()
 		Field::$types = [
 			'test' => [
 				'props' => [
-					'foo' => function ($foo) {
-						return $foo;
-					}
+					'foo' => fn ($foo) => $foo
 				]
 			]
 		];
@@ -998,9 +986,7 @@ public function testApi()
 		// return simple string
 		Field::$types = [
 			'test' => [
-				'api' => function () {
-					return 'Hello World';
-				}
+				'api' => fn () => 'Hello World'
 			]
 		];
 
diff --git a/tests/Form/Fields/Mixins/FilePickerMixinTest.php b/tests/Form/Fields/Mixins/FilePickerMixinTest.php
index e49af812ee..edabe94c82 100644
--- a/tests/Form/Fields/Mixins/FilePickerMixinTest.php
+++ b/tests/Form/Fields/Mixins/FilePickerMixinTest.php
@@ -34,9 +34,7 @@ public function testPageFiles()
 			'test' => [
 				'mixins'  => ['filepicker'],
 				'methods' => [
-					'files' => function () {
-						return $this->filepicker()['data'];
-					}
+					'files' => fn () => $this->filepicker()['data']
 				]
 			]
 		];
@@ -68,9 +66,7 @@ public function testFileFiles()
 			'test' => [
 				'mixins'  => ['filepicker'],
 				'methods' => [
-					'files' => function () {
-						return $this->filepicker()['data'];
-					}
+					'files' => fn () => $this->filepicker()['data']
 				]
 			]
 		];
@@ -102,9 +98,7 @@ public function testUserFiles()
 			'test' => [
 				'mixins'  => ['filepicker'],
 				'methods' => [
-					'files' => function () {
-						return $this->filepicker()['data'];
-					}
+					'files' => fn () => $this->filepicker()['data']
 				]
 			]
 		];
@@ -136,9 +130,7 @@ public function testSiteFiles()
 			'test' => [
 				'mixins'  => ['filepicker'],
 				'methods' => [
-					'files' => function () {
-						return $this->filepicker()['data'];
-					}
+					'files' => fn () => $this->filepicker()['data']
 				]
 			]
 		];
@@ -169,16 +161,12 @@ public function testCustomQuery()
 			'test' => [
 				'mixins'  => ['filepicker'],
 				'props' => [
-					'query' => function (string|null $query = null) {
-						return $query;
-					}
+					'query' => fn (string|null $query = null) => $query
 				],
 				'methods' => [
-					'files' => function () {
-						return $this->filepicker([
-							'query' => $this->query
-						])['data'];
-					}
+					'files' => fn () => $this->filepicker([
+						'query' => $this->query
+					])['data']
 				]
 			]
 		];
@@ -213,18 +201,12 @@ public function testMap()
 			'test' => [
 				'mixins'  => ['filepicker'],
 				'props' => [
-					'query' => function (string|null $query = null) {
-						return $query;
-					}
+					'query' => fn (string|null $query = null) => $query
 				],
 				'methods' => [
-					'files' => function () {
-						return $this->filepicker([
-							'map' => function ($file) {
-								return $file->id();
-							}
-						])['data'];
-					}
+					'files' => fn () => $this->filepicker([
+						'map' => fn ($file) => $file->id()
+					])['data']
 				]
 			]
 		];
diff --git a/tests/Form/Fields/Mixins/PagePickerMixinTest.php b/tests/Form/Fields/Mixins/PagePickerMixinTest.php
index bd51252302..7cead2b9a6 100644
--- a/tests/Form/Fields/Mixins/PagePickerMixinTest.php
+++ b/tests/Form/Fields/Mixins/PagePickerMixinTest.php
@@ -23,9 +23,7 @@ public function testPagesWithoutParent()
 				'test' => [
 					'mixins'  => ['pagepicker'],
 					'methods' => [
-						'pages' => function () {
-							return $this->pagepicker();
-						}
+						'pages' => fn () => $this->pagepicker()
 					]
 				]
 			],
@@ -68,11 +66,9 @@ public function testPagesWithParent()
 				'test' => [
 					'mixins'  => ['pagepicker'],
 					'methods' => [
-						'pages' => function () {
-							return $this->pagepicker([
-								'parent' => 'a'
-							]);
-						}
+						'pages' => fn () => $this->pagepicker([
+							'parent' => 'a'
+						])
 					]
 				]
 			],
@@ -118,11 +114,9 @@ public function testPageChildren()
 				'test' => [
 					'mixins'  => ['pagepicker'],
 					'methods' => [
-						'pages' => function () {
-							return $this->pagepicker([
-								'query' => 'page.children'
-							]);
-						}
+						'pages' => fn () => $this->pagepicker([
+							'query' => 'page.children'
+						])
 					]
 				]
 			],
@@ -170,12 +164,10 @@ public function testPageChildrenWithoutSubpages()
 				'test' => [
 					'mixins'  => ['pagepicker'],
 					'methods' => [
-						'pages' => function () {
-							return $this->pagepicker([
-								'query'    => 'page.children',
-								'subpages' => false
-							]);
-						}
+						'pages' => fn () => $this->pagepicker([
+							'query'    => 'page.children',
+							'subpages' => false
+						])
 					]
 				]
 			],
@@ -219,14 +211,10 @@ public function testMap()
 				'test' => [
 					'mixins'  => ['pagepicker'],
 					'methods' => [
-						'pages' => function () {
-							return $this->pagepicker([
-								'query' => 'page.children',
-								'map'   => function ($page) {
-									return $page->id();
-								}
-							]);
-						}
+						'pages' => fn () => $this->pagepicker([
+							'query' => 'page.children',
+							'map'   => fn ($page) => $page->id()
+						])
 					]
 				]
 			],
diff --git a/tests/Form/Fields/Mixins/UserPickerMixinTest.php b/tests/Form/Fields/Mixins/UserPickerMixinTest.php
index f06436a743..67220f47b1 100644
--- a/tests/Form/Fields/Mixins/UserPickerMixinTest.php
+++ b/tests/Form/Fields/Mixins/UserPickerMixinTest.php
@@ -36,9 +36,7 @@ public function testUsersWithoutQuery()
 			'test' => [
 				'mixins'  => ['userpicker'],
 				'methods' => [
-					'users' => function () {
-						return $this->userpicker()['data'];
-					}
+					'users' => fn () => $this->userpicker()['data']
 				]
 			]
 		];
@@ -65,11 +63,9 @@ public function testUsersWithQuery()
 			'test' => [
 				'mixins'  => ['userpicker'],
 				'methods' => [
-					'users' => function () {
-						return $this->userpicker([
-							'query' => 'kirby.users.role("editor")'
-						])['data'];
-					}
+					'users' => fn () => $this->userpicker([
+						'query' => 'kirby.users.role("editor")'
+					])['data']
 				]
 			]
 		];
@@ -95,13 +91,9 @@ public function testMap()
 			'test' => [
 				'mixins'  => ['userpicker'],
 				'methods' => [
-					'users' => function () {
-						return $this->userpicker([
-							'map' => function ($user) {
-								return $user->email();
-							}
-						])['data'];
-					}
+					'users' => fn () => $this->userpicker([
+						'map' => fn ($user) => $user->email()
+					])['data']
 				]
 			]
 		];
diff --git a/tests/Form/FormTest.php b/tests/Form/FormTest.php
index 963f2611c7..ae4464df6a 100644
--- a/tests/Form/FormTest.php
+++ b/tests/Form/FormTest.php
@@ -418,12 +418,8 @@ public function testPageFormWithClosures()
 
 		$form = Form::for($page, [
 			'values' => [
-				'a' => function ($value) {
-					return $value . 'A';
-				},
-				'b' => function ($value) {
-					return $value . 'B';
-				},
+				'a' => fn ($value) => $value . 'A',
+				'b' => fn ($value) => $value . 'B'
 			]
 		]);
 
diff --git a/tests/Form/ValidationsTest.php b/tests/Form/ValidationsTest.php
index 1df3ba2db8..b623e86ced 100644
--- a/tests/Form/ValidationsTest.php
+++ b/tests/Form/ValidationsTest.php
@@ -20,9 +20,7 @@ public function setUp(): void
 		Field::$types = [
 			'test' => [
 				'props' => [
-					'options' => function (array $options = []) {
-						return $options;
-					}
+					'options' => fn (array $options = []) => $options
 				]
 			]
 		];
diff --git a/tests/Http/ResponseTest.php b/tests/Http/ResponseTest.php
index 5d747ac9c7..a3da4dcc7a 100644
--- a/tests/Http/ResponseTest.php
+++ b/tests/Http/ResponseTest.php
@@ -98,9 +98,11 @@ public function testDownloadWithMissingFile()
 	 */
 	public function testGuardAgainstOutput()
 	{
-		$result = Response::guardAgainstOutput(function ($arg1, $arg2) {
-			return $arg1 . '-' . $arg2;
-		}, '12', '34');
+		$result = Response::guardAgainstOutput(
+			fn ($arg1, $arg2) => $arg1 . '-' . $arg2,
+			'12',
+			'34'
+		);
 
 		$this->assertSame('12-34', $result);
 	}
@@ -112,9 +114,11 @@ public function testGuardAgainstOutputWithSubsequentOutput()
 	{
 		HeadersSent::$value = true;
 
-		$result = Response::guardAgainstOutput(function ($arg1, $arg2) {
-			return $arg1 . '-' . $arg2;
-		}, '12', '34');
+		$result = Response::guardAgainstOutput(
+			fn ($arg1, $arg2) => $arg1 . '-' . $arg2,
+			'12',
+			'34'
+		);
 
 		$this->assertSame('12-34', $result);
 	}
diff --git a/tests/Http/RouteTest.php b/tests/Http/RouteTest.php
index e34b25e48d..65a4bb4223 100644
--- a/tests/Http/RouteTest.php
+++ b/tests/Http/RouteTest.php
@@ -15,9 +15,7 @@ public function _route()
 
 	public function testConstruct()
 	{
-		$route = new Route('/', 'POST', $func = function () {
-			return 'test';
-		});
+		$route = new Route('/', 'POST', $func = fn () => 'test');
 
 		$this->assertSame('', $route->pattern());
 		$this->assertSame('POST', $route->method());
diff --git a/tests/Http/RouterTest.php b/tests/Http/RouterTest.php
index fd865dfa39..ea87dfdcb2 100644
--- a/tests/Http/RouterTest.php
+++ b/tests/Http/RouterTest.php
@@ -135,9 +135,7 @@ public function testAfterEach()
 			[
 				[
 					'pattern' => '/',
-					'action'  => function () {
-						return 'test';
-					}
+					'action'  => fn () => 'test'
 				]
 			],
 			$hooks
@@ -225,9 +223,7 @@ public function testNextAfterEach()
 				],
 				[
 					'pattern' => 'a',
-					'action'  => function () {
-						return 'a';
-					}
+					'action'  => fn () => 'a'
 				]
 			],
 			$hooks
diff --git a/tests/Panel/Areas/PluginSearchesTest.php b/tests/Panel/Areas/PluginSearchesTest.php
index 8c00d44fec..2039816a35 100644
--- a/tests/Panel/Areas/PluginSearchesTest.php
+++ b/tests/Panel/Areas/PluginSearchesTest.php
@@ -22,9 +22,7 @@ public function testLegacyPluginSearch(): void
 					'search' => 'test',
 					'searches' => [
 						'test' => [
-							'query' => function (string|null $query = null) {
-								return [['a'], ['b'], ['c']];
-							},
+							'query' => fn (string|null $query = null) => [['a'], ['b'], ['c']]
 						]
 					]
 				]
diff --git a/tests/Panel/Areas/PluginTest.php b/tests/Panel/Areas/PluginTest.php
index 049e25db4f..bc148b6f22 100644
--- a/tests/Panel/Areas/PluginTest.php
+++ b/tests/Panel/Areas/PluginTest.php
@@ -14,11 +14,9 @@ public function testView(): void
 					'views' => [
 						[
 							'pattern' => 'foo',
-							'action'  => function () {
-								return [
-									'component' => 'k-foo-view'
-								];
-							}
+							'action'  => fn () => [
+								'component' => 'k-foo-view'
+							]
 						]
 					]
 				]
@@ -40,21 +38,17 @@ public function testViewWhen(): void
 					'views' => [
 						[
 							'pattern' => 'foo',
-							'when' => fn () => true,
-							'action'  => function () {
-								return [
-									'component' => 'k-foo-view',
-								];
-							}
+							'when'    => fn () => true,
+							'action'  => fn () => [
+								'component' => 'k-foo-view',
+							]
 						],
 						[
 							'pattern' => 'bar',
-							'when' => fn () => false,
-							'action'  => function () {
-								return [
-									'component' => 'k-bar-view',
-								];
-							}
+							'when'    => fn () => false,
+							'action'  => fn () => [
+								'component' => 'k-bar-view',
+							]
 						]
 					]
 				]
diff --git a/tests/Panel/DropdownTest.php b/tests/Panel/DropdownTest.php
index c5a68638af..8bfa602fe7 100644
--- a/tests/Panel/DropdownTest.php
+++ b/tests/Panel/DropdownTest.php
@@ -148,14 +148,12 @@ public function testRoutes(): void
 	{
 		$dropdown = [
 			'pattern' => 'test',
-			'action'  => $action = function () {
-				return [
-					[
-						'text' => 'Test',
-						'link' => '/test'
-					]
-				];
-			}
+			'action'  => $action = fn () => [
+				[
+					'text' => 'Test',
+					'link' => '/test'
+				]
+			]
 		];
 
 		$routes = Dropdown::routes(
@@ -187,14 +185,12 @@ public function testRoutesForDropdownsWithOptions(): void
 			'dropdowns' => [
 				'test' => [
 					'pattern' => 'test',
-					'options' => $action = function () {
-						return [
-							[
-								'text' => 'Test',
-								'link' => '/test'
-							]
-						];
-					}
+					'options' => $action = fn () => [
+						[
+							'text' => 'Test',
+							'link' => '/test'
+						]
+					]
 				]
 			]
 		];
@@ -221,14 +217,12 @@ public function testRoutesForDropdownsWithShortcut(): void
 	{
 		$area = [
 			'dropdowns' => [
-				'test' => $action = function () {
-					return [
-						[
-							'text' => 'Test',
-							'link' => '/test'
-						]
-					];
-				}
+				'test' => $action = fn () => [
+					[
+						'text' => 'Test',
+						'link' => '/test'
+					]
+				]
 			]
 		];
 
diff --git a/tests/Panel/FileTest.php b/tests/Panel/FileTest.php
index 56f4c18526..85fb810863 100644
--- a/tests/Panel/FileTest.php
+++ b/tests/Panel/FileTest.php
@@ -254,7 +254,7 @@ public function testDragTextCustomMarkdown()
 				'panel' => [
 					'kirbytext' => false,
 					'markdown' => [
-						'fileDragText' => function (\Kirby\Cms\File $file, string $url) {
+						'fileDragText' => function (ModelFile $file, string $url) {
 							if ($file->extension() === 'heic') {
 								return sprintf('![](%s)', $url);
 							}
@@ -295,7 +295,7 @@ public function testDragTextCustomKirbytext()
 			'options' => [
 				'panel' => [
 					'kirbytext' => [
-						'fileDragText' => function (\Kirby\Cms\File $file, string $url) {
+						'fileDragText' => function (ModelFile $file, string $url) {
 							if ($file->extension() === 'heic') {
 								return sprintf('(image: %s)', $url);
 							}
diff --git a/tests/Panel/ModelTest.php b/tests/Panel/ModelTest.php
index 0eec3d104f..988523dcdf 100644
--- a/tests/Panel/ModelTest.php
+++ b/tests/Panel/ModelTest.php
@@ -4,6 +4,7 @@
 
 use Kirby\Cms\App;
 use Kirby\Cms\ContentLock;
+use Kirby\Cms\File as ModelFile;
 use Kirby\Cms\Page as ModelPage;
 use Kirby\Cms\Site as ModelSite;
 use Kirby\Filesystem\Asset;
@@ -150,7 +151,7 @@ public function testDragTextFromCallbackMarkdown()
 			'options' => [
 				'panel' => [
 					'markdown' => [
-						'fileDragText' => function (\Kirby\Cms\File $file, string $url) {
+						'fileDragText' => function (ModelFile $file, string $url) {
 							if ($file->extension() === 'heic') {
 								return sprintf('![](%s)', $file->id());
 							}
@@ -193,7 +194,7 @@ public function testDragTextFromCallbackKirbytext()
 			'options' => [
 				'panel' => [
 					'kirbytext' => [
-						'fileDragText' => function (\Kirby\Cms\File $file, string $url) {
+						'fileDragText' => function (ModelFile $file, string $url) {
 							if ($file->extension() === 'heic') {
 								return sprintf('(image: %s)', $file->id());
 							}
diff --git a/tests/Panel/PageTest.php b/tests/Panel/PageTest.php
index 279f6b75ea..7f96953ebf 100644
--- a/tests/Panel/PageTest.php
+++ b/tests/Panel/PageTest.php
@@ -178,7 +178,7 @@ public function testDragTextCustomMarkdown()
 				'panel' => [
 					'kirbytext' => false,
 					'markdown' => [
-						'pageDragText' => function (\Kirby\Cms\Page $page) {
+						'pageDragText' => function (ModelPage $page) {
 							return sprintf('Links sind toll: %s', $page->url());
 						},
 					]
@@ -209,7 +209,7 @@ public function testDragTextCustomKirbytext()
 			'options' => [
 				'panel' => [
 					'kirbytext' => [
-						'pageDragText' => function (\Kirby\Cms\Page $page) {
+						'pageDragText' => function (ModelPage $page) {
 							return sprintf('Links sind toll: %s', $page->url());
 						},
 					]
diff --git a/tests/Panel/PanelTest.php b/tests/Panel/PanelTest.php
index 564ecfe332..a9e53c6f7e 100644
--- a/tests/Panel/PanelTest.php
+++ b/tests/Panel/PanelTest.php
@@ -539,14 +539,12 @@ public function testRoutesForDropdowns(): void
 			'dropdowns' => [
 				'test' => [
 					'pattern' => 'test',
-					'action'  => $action = function () {
-						return [
-							[
-								'text' => 'Test',
-								'link' => '/test'
-							]
-						];
-					}
+					'action'  => $action = fn () => [
+						[
+							'text' => 'Test',
+							'link' => '/test'
+						]
+					]
 				]
 			]
 		];
@@ -575,14 +573,12 @@ public function testRoutesForDropdownsWithOptions(): void
 			'dropdowns' => [
 				'test' => [
 					'pattern' => 'test',
-					'options' => $action = function () {
-						return [
-							[
-								'text' => 'Test',
-								'link' => '/test'
-							]
-						];
-					}
+					'options' => $action = fn () => [
+						[
+							'text' => 'Test',
+							'link' => '/test'
+						]
+					]
 				]
 			]
 		];
@@ -609,14 +605,12 @@ public function testRoutesForDropdownsWithShortcut(): void
 	{
 		$area = [
 			'dropdowns' => [
-				'test' => $action = function () {
-					return [
-						[
-							'text' => 'Test',
-							'link' => '/test'
-						]
-					];
-				}
+				'test' => $action = fn () => [
+					[
+						'text' => 'Test',
+						'link' => '/test'
+					]
+				]
 			]
 		];
 
diff --git a/tests/Query/QueryDefaultFunctionsTest.php b/tests/Query/QueryDefaultFunctionsTest.php
index 09540d87ae..1fd486a5f1 100644
--- a/tests/Query/QueryDefaultFunctionsTest.php
+++ b/tests/Query/QueryDefaultFunctionsTest.php
@@ -35,9 +35,7 @@ public function testCollection()
 				]
 			],
 			'collections' => [
-				'test' => function ($pages) {
-					return $pages;
-				}
+				'test' => fn ($pages) => $pages
 			]
 		]);
 
diff --git a/tests/Toolkit/CollectionConverterTest.php b/tests/Toolkit/CollectionConverterTest.php
index 991d87af19..c8c0864840 100644
--- a/tests/Toolkit/CollectionConverterTest.php
+++ b/tests/Toolkit/CollectionConverterTest.php
@@ -23,9 +23,7 @@ public function testToArrayMap()
 		$this->assertSame([
 			'one'   => 'einsy',
 			'two'   => 'zweiy'
-		], $collection->toArray(function ($item) {
-			return $item . 'y';
-		}));
+		], $collection->toArray(fn ($item) => $item . 'y'));
 	}
 
 	public function testToJson()
diff --git a/tests/Toolkit/CollectionMutatorTest.php b/tests/Toolkit/CollectionMutatorTest.php
index 0f56321123..6801718632 100644
--- a/tests/Toolkit/CollectionMutatorTest.php
+++ b/tests/Toolkit/CollectionMutatorTest.php
@@ -130,9 +130,7 @@ public function testMap()
 		]);
 
 		$this->assertSame('zwei', $collection->two());
-		$collection->map(function ($item) {
-			return $item . '-ish';
-		});
+		$collection->map(fn ($item) => $item . '-ish');
 		$this->assertSame('zwei-ish', $collection->two());
 	}
 
diff --git a/tests/Toolkit/CollectionTest.php b/tests/Toolkit/CollectionTest.php
index 3d77123474..ce9f7a893f 100644
--- a/tests/Toolkit/CollectionTest.php
+++ b/tests/Toolkit/CollectionTest.php
@@ -183,11 +183,9 @@ public function testEmpty()
 	 */
 	public function testFilter()
 	{
-		$func = function ($element) {
-			return ($element === 'My second element') ? true : false;
-		};
-
-		$filtered = $this->collection->filter($func);
+		$filtered = $this->collection->filter(
+			fn ($element) => $element === 'My second element'
+		);
 
 		$this->assertSame('My second element', $filtered->first());
 		$this->assertSame('My second element', $filtered->last());
@@ -336,9 +334,7 @@ public function testGroupWithInvalidKey()
 		$this->expectException(Exception::class);
 		$this->expectExceptionMessage('Invalid grouping value for key: a');
 
-		$collection->group(function ($item) {
-			return false;
-		});
+		$collection->group(fn ($item) => false);
 	}
 
 	/**
@@ -389,10 +385,7 @@ public function testGroupStringObject()
 			'group'    => new StringObject('client')
 		];
 
-		$groups = $collection->group(function ($item) {
-			return $item['group'];
-		});
-
+		$groups = $collection->group(fn ($item) => $item['group']);
 		$this->assertCount(2, $groups->admin());
 		$this->assertCount(1, $groups->client());
 
@@ -982,9 +975,9 @@ public function testValues()
 	 */
 	public function testValuesMap()
 	{
-		$values = $this->collection->values(function ($item) {
-			return Str::after($item, 'My ');
-		});
+		$values = $this->collection->values(
+			fn ($item) => Str::after($item, 'My ')
+		);
 
 		$this->assertSame([
 			'first element',
diff --git a/tests/Toolkit/DomTest.php b/tests/Toolkit/DomTest.php
index 9a65724929..5d8c56ba82 100644
--- a/tests/Toolkit/DomTest.php
+++ b/tests/Toolkit/DomTest.php
@@ -1850,9 +1850,10 @@ public function testSanitize(string $code, array $options, string $expectedCode,
 		$dom    = new Dom($code, 'XML');
 		$errors = $dom->sanitize($options);
 
-		$this->assertSame($expectedErrors, array_map(function ($error) {
-			return $error->getMessage();
-		}, $errors));
+		$this->assertSame(
+			$expectedErrors,
+			array_map(fn ($error) => $error->getMessage(), $errors)
+		);
 		$this->assertSame($expectedCode, $dom->toString());
 	}
 
diff --git a/tests/Toolkit/I18nTest.php b/tests/Toolkit/I18nTest.php
index 458115e091..08a628603e 100644
--- a/tests/Toolkit/I18nTest.php
+++ b/tests/Toolkit/I18nTest.php
@@ -430,17 +430,11 @@ public function testTranslateCountWithCallback()
 	{
 		I18n::$translations = [
 			'en' => [
-				'car' => function ($count) {
-					switch ($count) {
-						case 0:
-							return 'No car';
-						case 1:
-							return 'One car';
-						case in_array($count, [2, 3, 4]) === true:
-							return 'Few cars';
-						default:
-							return 'Many cars';
-					}
+				'car' => fn ($count) => match ($count) {
+					0       => 'No car',
+					1       => 'One car',
+					2, 3, 4 => 'Few cars',
+					default => 'Many cars'
 				}
 			]
 		];