adds interface tests

mocks/ChildInterface.php

@@ -4,5 +4,7 @@
 
 interface ChildInterface
 {
+    public const int ANYTHING = 0;
 
+    public function getAnything(RootInterface $root): int;
 }

mocks/RootInterface.php

@@ -2,7 +2,15 @@
 
 namespace Souplette\Chicot\Mocks;
 
+/**
+ * Das root.
+ */
 interface RootInterface
 {
+    /**
+     * Everything
+     */
+    public const int EVERYTHING = 42;
 
+    public function getEverything(): int;
 }

tests/ExtensionInterfaceTest.php

@@ -0,0 +1,60 @@
+<?php declare(strict_types=1);
+
+namespace Souplette\Chicot\Tests;
+
+use PHPUnit\Framework\Attributes\DataProvider;
+use ReflectionClass;
+use Souplette\Chicot\Mocks\ChildInterface;
+use Souplette\Chicot\Mocks\RootInterface;
+
+final class ExtensionInterfaceTest extends GeneratorTestCase
+{
+    #[DataProvider('generateInterfaceProvider')]
+    public function testGenerateInterface(string $name, string $expected): void
+    {
+        $code = self::generateStubs('acme', classes: [
+            new ReflectionClass($name),
+        ]);
+        self::assertCodeEq($expected, $code);
+    }
+
+    public static function generateInterfaceProvider(): iterable
+    {
+        yield 'interface' => [
+            RootInterface::class,
+            <<<'PHP'
+            /**
+             * Das root.
+             */
+            interface RootInterface
+            {
+                /**
+                 * Everything
+                 */
+                public const int EVERYTHING = 42;
+                public function getEverything() : int;
+            }
+            PHP,
+        ];
+        yield 'child interface' => [
+            ChildInterface::class,
+            <<<'PHP'
+            interface ChildInterface
+            {
+                public const int ANYTHING = 0;
+                public function getAnything(\Souplette\Chicot\Mocks\RootInterface $root) : int;
+            }
+            PHP,
+        ];
+    }
+
+    protected static function assertCodeEq(string $expected, string $actual): void
+    {
+        $expected = <<<PHP
+        namespace Souplette\Chicot\Mocks;
+
+        {$expected}
+        PHP;
+        parent::assertCodeEq($expected, $actual);
+    }
+}