Implement UnwrapArrayMap and UnwrapArrayFilter mutators (#513)

* Implement UnwrapArrayMap and UnwrapArrayFilter mutators

* Add more tests examples and fix wrongly capitalized funcation name

* Fix typos in tests provider for UnwrapArrayFilter mutator

src/Mutator/Unwrap/AbstractUnwrapMutator.php

@@ -0,0 +1,42 @@
+<?php
+/**
+ * Copyright © 2017-2018 Maks Rafalko
+ *
+ * License: https://opensource.org/licenses/BSD-3-Clause New BSD License
+ */
+
+declare(strict_types=1);
+
+namespace Infection\Mutator\Unwrap;
+
+use Infection\Mutator\Util\Mutator;
+use PhpParser\Node;
+
+/**
+ * @internal
+ */
+abstract class AbstractUnwrapMutator extends Mutator
+{
+    abstract protected function getFunctionName(): string;
+
+    abstract protected function getParameterIndex(): int;
+
+    /**
+     * Replaces "$a = function(arg1, arg2);" with "$a = arg1;"
+     *
+     * @return Node\Param;
+     */
+    final public function mutate(Node $node)
+    {
+        return $node->args[$this->getParameterIndex()];
+    }
+
+    final protected function mutatesNode(Node $node): bool
+    {
+        if (!$node instanceof Node\Expr\FuncCall) {
+            return false;
+        }
+
+        return $node->name->toLowerString() === strtolower($this->getFunctionName());
+    }
+}

src/Mutator/Unwrap/UnwrapArrayFilter.php

@@ -0,0 +1,26 @@
+<?php
+/**
+ * Copyright © 2017-2018 Maks Rafalko
+ *
+ * License: https://opensource.org/licenses/BSD-3-Clause New BSD License
+ */
+
+declare(strict_types=1);
+
+namespace Infection\Mutator\Unwrap;
+
+/**
+ * @internal
+ */
+final class UnwrapArrayFilter extends AbstractUnwrapMutator
+{
+    protected function getFunctionName(): string
+    {
+        return 'array_filter';
+    }
+
+    protected function getParameterIndex(): int
+    {
+        return 0;
+    }
+}

src/Mutator/Unwrap/UnwrapArrayMap.php

@@ -0,0 +1,26 @@
+<?php
+/**
+ * Copyright © 2017-2018 Maks Rafalko
+ *
+ * License: https://opensource.org/licenses/BSD-3-Clause New BSD License
+ */
+
+declare(strict_types=1);
+
+namespace Infection\Mutator\Unwrap;
+
+/**
+ * @internal
+ */
+final class UnwrapArrayMap extends AbstractUnwrapMutator
+{
+    protected function getFunctionName(): string
+    {
+        return 'array_map';
+    }
+
+    protected function getParameterIndex(): int
+    {
+        return 1;
+    }
+}

src/Mutator/Util/MutatorProfile.php

@@ -33,6 +33,7 @@ final class MutatorProfile
         '@sort' => self::SORT,
         '@zero_iteration' => self::ZERO_ITERATION,
         '@cast' => self::CAST,
+        '@unwrap' => self::UNWRAP,
 
         //Special Profiles
         '@default' => self::DEFAULT,
@@ -159,6 +160,11 @@ final class MutatorProfile
         Mutator\Cast\CastString::class,
     ];
 
+    public const UNWRAP = [
+        Mutator\Unwrap\UnwrapArrayMap::class,
+        Mutator\Unwrap\UnwrapArrayFilter::class,
+    ];
+
     public const DEFAULT = [
         '@arithmetic',
         '@boolean',
@@ -278,5 +284,9 @@ final class MutatorProfile
         'CastInt' => Mutator\Cast\CastInt::class,
         'CastObject' => Mutator\Cast\CastObject::class,
         'CastString' => Mutator\Cast\CastString::class,
+
+        // Unwrap
+        'UnwrapArrayMap' => Mutator\Unwrap\UnwrapArrayMap::class,
+        'UnwrapArrayFilter' => Mutator\Unwrap\UnwrapArrayFilter::class,
     ];
 }

tests/Mutator/Unwrap/UnwrapArrayFilterTest.php

@@ -0,0 +1,153 @@
+<?php
+/**
+ * Copyright © 2017-2018 Maks Rafalko
+ *
+ * License: https://opensource.org/licenses/BSD-3-Clause New BSD License
+ */
+
+declare(strict_types=1);
+
+namespace Infection\Tests\Mutator\Unwrap;
+
+use Infection\Tests\Mutator\AbstractMutatorTestCase;
+
+/**
+ * @internal
+ */
+final class UnwrapArrayFilterTest extends AbstractMutatorTestCase
+{
+    /**
+     * @dataProvider provideMutationCases
+     */
+    public function test_mutator($input, $expected = null): void
+    {
+        $this->doTest($input, $expected);
+    }
+
+    public function provideMutationCases(): \Generator
+    {
+        yield 'It mutates correctly when provided with a array' => [
+            <<<'PHP'
+<?php
+
+$a = array_filter(['A', 1, 'C'], 'is_int');
+PHP
+            ,
+            <<<'PHP'
+<?php
+
+$a = ['A', 1, 'C'];
+PHP
+        ];
+
+        yield 'It mutates correctly when provided with a constant' => [
+            <<<'PHP'
+<?php
+
+$a = array_filter(\Class_With_Const::Const, 'is_int');
+PHP
+            ,
+            <<<'PHP'
+<?php
+
+$a = \Class_With_Const::Const;
+PHP
+        ];
+
+        yield 'It mutates correctly when a backslash is in front of array_filter' => [
+            <<<'PHP'
+<?php
+
+$a = \array_filter(['A', 1, 'C'], 'is_int');
+PHP
+            ,
+            <<<'PHP'
+<?php
+
+$a = ['A', 1, 'C'];
+PHP
+        ];
+
+        yield 'It does not mutate other array_ calls' => [
+            <<<'PHP'
+<?php
+
+$a = array_map('strtolower', ['A', 'B', 'C']);
+PHP
+        ];
+
+        yield 'It does not mutate functions named array_filter' => [
+            <<<'PHP'
+<?php
+
+function array_filter($text, $other)
+{
+}
+PHP
+        ];
+
+        yield 'It mutates correctly within if statements' => [
+            <<<'PHP'
+<?php
+
+$a = ['A', 1, 'C'];
+if (array_filter($a, 'is_int') === $a) {
+    return true;
+}
+PHP
+            ,
+            <<<'PHP'
+<?php
+
+$a = ['A', 1, 'C'];
+if ($a === $a) {
+    return true;
+}
+PHP
+        ];
+
+        yield 'It mutates correctly when array_filter is wrongly capitalized' => [
+            <<<'PHP'
+<?php
+
+$a = aRrAy_FiLtEr(['A', 1, 'C'], 'is_int');
+PHP
+            ,
+            <<<'PHP'
+<?php
+
+$a = ['A', 1, 'C'];
+PHP
+        ];
+
+        yield 'It mutates correctly when array_filter uses another function as input' => [
+            <<<'PHP'
+<?php
+
+$a = array_filter($foo->bar(), 'is_int');
+PHP
+            ,
+            <<<'PHP'
+<?php
+
+$a = $foo->bar();
+PHP
+        ];
+
+        yield 'It mutates correctly when provided with a more complex situation' => [
+            <<<'PHP'
+<?php
+
+$a = array_map('strtolower', array_filter(['A', 1, 'C'], function($char): bool {
+    return !is_int($char);
+}));
+PHP
+            ,
+            <<<'PHP'
+<?php
+
+$a = array_map('strtolower', ['A', 1, 'C']);
+PHP
+        ];
+    }
+}