#597 Array item removal mutator

resources/schema.json

@@ -115,6 +115,35 @@
                             }
                         ]
                     }
+                },
+                "ArrayItemRemoval": {
+                    "type": {
+                        "anyOf": [
+                            {
+                                "type": "boolean"
+                            },
+                            {
+                                "type": "object",
+                                "additionalProperties": false,
+                                "properties": {
+                                    "settings": {
+                                        "type": "object",
+                                        "additionalProperties": false,
+                                        "properties": {
+                                            "remove": {
+                                                "type": "string",
+                                                "enum": ["first", "last", "all"]
+                                            },
+                                            "limit": {
+                                                "type": "integer",
+                                                "minimum": 1
+                                            }
+                                        }
+                                    }
+                                }
+                            }
+                        ]
+                    }
                 }
             }
         },

src/Mutator/Removal/ArrayItemRemoval.php

@@ -0,0 +1,130 @@
+<?php
+/**
+ * This code is licensed under the BSD 3-Clause License.
+ *
+ * Copyright (c) 2017-2019, Maks Rafalko
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * * Redistributions of source code must retain the above copyright notice, this
+ *   list of conditions and the following disclaimer.
+ *
+ * * Redistributions in binary form must reproduce the above copyright notice,
+ *   this list of conditions and the following disclaimer in the documentation
+ *   and/or other materials provided with the distribution.
+ *
+ * * Neither the name of the copyright holder nor the names of its
+ *   contributors may be used to endorse or promote products derived from
+ *   this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+declare(strict_types=1);
+
+namespace Infection\Mutator\Removal;
+
+use Generator;
+use Infection\Config\Exception\InvalidConfigException;
+use Infection\Mutator\Util\Mutator;
+use Infection\Mutator\Util\MutatorConfig;
+use PhpParser\Node;
+
+/**
+ * @internal
+ */
+final class ArrayItemRemoval extends Mutator
+{
+    private const DEFAULT_SETTINGS = [
+        'remove' => 'first',
+        'limit' => PHP_INT_MAX,
+    ];
+
+    /** @var string first|last|all */
+    private $remove;
+    /** @var int */
+    private $limit;
+
+    public function __construct(MutatorConfig $config)
+    {
+        parent::__construct($config);
+
+        $settings = $this->getResultSettings();
+
+        $this->remove = $settings['remove'];
+        $this->limit = $settings['limit'];
+    }
+
+    /**
+     * @param Node|Node\Expr\Array_  $arrayNode
+     */
+    public function mutate(Node $arrayNode): Generator
+    {
+        foreach ($this->getItemsIndexes($arrayNode->items) as $indexToRemove) {
+            $newArrayNode = clone $arrayNode;
+            unset($newArrayNode->items[$indexToRemove]);
+
+            yield $newArrayNode;
+        }
+    }
+
+    protected function mutatesNode(Node $node): bool
+    {
+        return $node instanceof Node\Expr\Array_ && \count($node->items);
+    }
+
+    private function getItemsIndexes(array $items): array
+    {
+        switch ($this->remove) {
+            case 'first':
+                return [0];
+            case 'last':
+                return [\count($items) - 1];
+            default:
+                return \range(0, \min(\count($items), $this->limit) - 1);
+        }
+    }
+
+    private function getResultSettings(): array
+    {
+        $settings = \array_merge(self::DEFAULT_SETTINGS, $this->getSettings());
+
+        if (!\is_string($settings['remove'])) {
+            $this->throwConfigException('remove');
+        }
+
+        $settings['remove'] = \strtolower($settings['remove']);
+
+        if (!\in_array($settings['remove'], ['first', 'last', 'all'])) {
+            $this->throwConfigException('remove');
+        }
+
+        if (!\is_numeric($settings['limit']) || $settings['limit'] < 1) {
+            $this->throwConfigException('limit');
+        }
+
+        return $settings;
+    }
+
+    private function throwConfigException(string $property): void
+    {
+        $value = $this->getSettings()[$property];
+
+        throw new InvalidConfigException(sprintf(
+            'Invalid configuration of ArrayItemRemoval mutator. Setting `%s` is invalid (%s)',
+            $property,
+            \is_scalar($value) ? $value : '<' . \strtoupper(\gettype($value)) . '>'
+        ));
+    }
+}

src/Mutator/Util/MutatorProfile.php

@@ -158,6 +158,7 @@ final class MutatorProfile
     ];
 
     public const REMOVAL = [
+        Mutator\Removal\ArrayItemRemoval::class,
         Mutator\Removal\FunctionCallRemoval::class,
         Mutator\Removal\MethodCallRemoval::class,
     ];
@@ -327,6 +328,7 @@ final class MutatorProfile
         'PregMatchMatches' => Mutator\Regex\PregMatchMatches::class,
 
         //Removal
+        'ArrayItemRemoval' => Mutator\Removal\ArrayItemRemoval::class,
         'FunctionCallRemoval' => Mutator\Removal\FunctionCallRemoval::class,
         'MethodCallRemoval' => Mutator\Removal\MethodCallRemoval::class,
 

tests/Mutator/Removal/ArrayItemRemovalTest.php

@@ -0,0 +1,165 @@
+<?php
+/**
+ * This code is licensed under the BSD 3-Clause License.
+ *
+ * Copyright (c) 2017-2019, Maks Rafalko
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * * Redistributions of source code must retain the above copyright notice, this
+ *   list of conditions and the following disclaimer.
+ *
+ * * Redistributions in binary form must reproduce the above copyright notice,
+ *   this list of conditions and the following disclaimer in the documentation
+ *   and/or other materials provided with the distribution.
+ *
+ * * Neither the name of the copyright holder nor the names of its
+ *   contributors may be used to endorse or promote products derived from
+ *   this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+declare(strict_types=1);
+
+namespace Infection\Tests\Mutator\Removal;
+
+use Generator;
+use Infection\Config\Exception\InvalidConfigException;
+use Infection\Tests\Mutator\AbstractMutatorTestCase;
+
+/**
+ * @internal
+ */
+final class ArrayItemRemovalTest extends AbstractMutatorTestCase
+{
+    /**
+     * @dataProvider provideMutationCases
+     */
+    public function test_mutator(string $input, $expected = null, array $settings = []): void
+    {
+        $this->doTest($input, $expected, $settings);
+    }
+
+    public function provideMutationCases(): Generator
+    {
+        yield 'It does not mutate empty arrays' => [
+            '<?php $a = [];',
+        ];
+
+        yield 'It removes only first item by default' => [
+            '<?php $a = [1, 2, 3];',
+            "<?php\n\n\$a = [2, 3];",
+        ];
+
+        yield 'It removes only last item when set to do so' => [
+            '<?php $a = [1, 2, 3];',
+            "<?php\n\n\$a = [1, 2];",
+            ['settings' => ['remove' => 'last']],
+        ];
+
+        yield 'It removes every item on by one when set to `all`' => [
+            '<?php $a = [1, 2, 3];',
+            [
+                "<?php\n\n\$a = [2, 3];",
+                "<?php\n\n\$a = [1, 3];",
+                "<?php\n\n\$a = [1, 2];",
+            ],
+            ['settings' => ['remove' => 'all']],
+        ];
+
+        yield 'It obeys limit when mutating arrays in `all` mode' => [
+            '<?php $a = [1, 2, 3];',
+            [
+                "<?php\n\n\$a = [2, 3];",
+                "<?php\n\n\$a = [1, 3];",
+            ],
+            ['settings' => ['remove' => 'all', 'limit' => 2]],
+        ];
+
+        yield 'It mutates arrays having required items count when removing `all` items' => [
+            '<?php $a = [1, 2];',
+            [
+                "<?php\n\n\$a = [2];",
+                "<?php\n\n\$a = [1];",
+            ],
+            ['settings' => ['remove' => 'all', 'limit' => 2]],
+        ];
+
+        yield 'It mutates correctly for limit value (1)' => [
+            '<?php $a = [1];',
+            [
+                "<?php\n\n\$a = [];",
+            ],
+            ['settings' => ['remove' => 'all', 'limit' => 1]],
+        ];
+    }
+
+    /**
+     * @dataProvider provideInvalidConfigurationCases
+     */
+    public function test_settings_validation(string $setting, $value, string $valueInError): void
+    {
+        $this->expectException(InvalidConfigException::class);
+        $this->expectExceptionMessage(sprintf(
+            'Invalid configuration of ArrayItemRemoval mutator. Setting `%s` is invalid (%s)',
+            $setting,
+            $valueInError
+        ));
+        $this->doTest(
+            '<?php $a = [1, 2, 3];',
+            "<?php\n\n\$a = [2, 3];",
+            ['settings' => [$setting => $value]]
+        );
+    }
+
+    public function provideInvalidConfigurationCases(): Generator
+    {
+        yield 'remove is null' => [
+            'remove', null, '<NULL>',
+        ];
+
+        yield 'remove is array' => [
+            'remove', [], '<ARRAY>',
+        ];
+
+        yield 'remove is not valid' => [
+            'remove', 'INVALID', 'INVALID',
+        ];
+
+        yield 'remove is not string' => [
+            'remove', 1, '1',
+        ];
+
+        yield 'limit is null' => [
+            'limit', null, '<NULL>',
+        ];
+
+        yield 'limit is array' => [
+            'limit', [], '<ARRAY>',
+        ];
+
+        yield 'limit is zero' => [
+            'limit', 0, '0',
+        ];
+
+        yield 'limit is negative' => [
+            'limit', -1, '-1',
+        ];
+
+        yield 'limit is not numeric' => [
+            'limit', 'INVALID', 'INVALID',
+        ];
+    }
+}