feat(expressions): add new fetch expression

tests/src/flextype/core/Entries/Expressions/FetchExpressionTest.php

@@ -0,0 +1,41 @@
+<?php
+
+use Flextype\Component\Filesystem\Filesystem;
+use function Glowy\Filesystem\filesystem;
+use function Flextype\entries;
+
+beforeEach(function() {
+    filesystem()->directory(FLEXTYPE_PATH_PROJECT . '/entries')->create();
+});
+
+afterEach(function (): void {
+    filesystem()->directory(FLEXTYPE_PATH_PROJECT . '/entries')->delete();
+});
+
+test('fetch expression', function () {
+
+    // 1.
+    $this->assertTrue(entries()->create('data', ['title' => 'Foo!', 'category' => 'foo']));
+    $this->assertTrue(entries()->create('foo-test', ['test1' => "[[ fetch('data').get('title') ]]", 
+                                                 'test2' => "[[ fetch('data').toJson() ]]", 
+                                                 'test3' => "[[ fetch('data').get('foo', 'FooDefault') ]]"]));
+    
+    $foo = entries()->fetch('foo-test');
+
+    expect($foo['test1'])->toBe('Foo!');
+    expect($foo['test2'])->toBeJson();
+    expect($foo['test3'])->toBe('FooDefault');
+
+    // 2.
+    $this->assertTrue(entries()->create('bar-test', ['test1' => "[[ fetch(const('FLEXTYPE_ROOT_DIR') ~ '/src/flextype/flextype.yaml').get('name') ]]", 
+                                                     'test2' => "[[ fetch(const('FLEXTYPE_ROOT_DIR') ~ '/src/flextype/flextype.yaml').toJson() ]]", 
+                                                     'test3' => "[[ fetch(const('FLEXTYPE_ROOT_DIR') ~ '/src/flextype/flextype.yaml').get('boo', 'Boo') ]]"]));
+
+    $bar = entries()->fetch('bar-test');
+
+    expect($bar['test1'])->toBe('Flextype');
+    expect($bar['test2'])->toBeJson();
+    expect($bar['test3'])->toBe('Boo');
+
+    // 3. @TODO test for fetch data from the urls...
+});