Allow Transformer instances in patches

Author: AydinHassan

src/Patch.php

@@ -5,19 +5,23 @@
 namespace PhpSchool\PhpWorkshop;
 
 use Closure;
+use PhpSchool\PhpWorkshop\Patch\Transformer;
 
 /**
  * This class is responsible for storing the modifications that should
  * be made to a PHP file. That includes insertions and transformers.
  * A transformer is a simple closure which should receives an AST
  * representation of the student's solution and it should return the modified AST.
+ *
+ * Transformers can also be class implementing `Transformer`.
+ *
  * An insertion is a block of code that can be inserted at the top or bottom of
  * the students solution.
  */
 final class Patch
 {
     /**
-     * @var array<CodeInsertion|Closure>
+     * @var array<CodeInsertion|Closure|Transformer>
      */
     private $modifications = [];
 
@@ -35,22 +39,23 @@ public function withInsertion(CodeInsertion $insertion): self
     }
 
     /**
-     * Add a new transformer (`Closure`). `Patch` is immutable so a new instance is returned.
+     * Add a new transformer (`Closure` OR `Transformer`). `Patch` is immutable so a new instance is returned.
      *
-     * @param Closure $closure
+     * @param Closure|Transformer $closure
      * @return self
      */
-    public function withTransformer(Closure $closure): self
+    public function withTransformer($closure): self
     {
         $new = clone $this;
         $new->modifications[] = $closure;
         return $new;
     }
 
     /**
-     * Retrieve all the modifications including insertions (`CodeInsertion`'s) & transformers (`Closure`'s)
+     * Retrieve all the modifications including insertions (`CodeInsertion`'s)
+     * & transformers (`Closure`'s OR `Transformer`'s)
      *
-     * @return array<CodeInsertion|Closure>
+     * @return array<CodeInsertion|Closure|Transformer>
      */
     public function getModifiers(): array
     {

test/PatchTest.php

@@ -19,7 +19,7 @@ public function testWithInsertion(): void
         $this->assertEquals([$insertion], $new->getModifiers());
     }
 
-    public function testWithTransformer(): void
+    public function testWithTransformerWithClosure(): void
     {
         $patch = new Patch();
         $transformer = function (array $statements) {
@@ -30,4 +30,42 @@ public function testWithTransformer(): void
         $this->assertEmpty($patch->getModifiers());
         $this->assertEquals([$transformer], $new->getModifiers());
     }
+
+    public function testWithTransformerWithTransformer(): void
+    {
+        $patch = new Patch();
+        $transformer = new class implements Patch\Transformer {
+            public function transform(array $ast): array
+            {
+                return $ast;
+            }
+        };
+
+        $new = $patch->withTransformer($transformer);
+        $this->assertNotSame($patch, $new);
+        $this->assertEmpty($patch->getModifiers());
+        $this->assertEquals([$transformer], $new->getModifiers());
+    }
+
+    public function testWithTransformerMultiple(): void
+    {
+        $transformer1 = new class implements Patch\Transformer {
+            public function transform(array $ast): array
+            {
+                return $ast;
+            }
+        };
+        $transformer2 = function (array $statements) {
+            return $statements;
+        };
+
+        $patch = new Patch();
+        $new = $patch
+            ->withTransformer($transformer1)
+            ->withTransformer($transformer2);
+
+        $this->assertNotSame($patch, $new);
+        $this->assertEmpty($patch->getModifiers());
+        $this->assertEquals([$transformer1, $transformer2], $new->getModifiers());
+    }
 }