Allow key deletion. Replace overridden indexed arrays (no merge).

- Fixed parameter errors, coverage analysis, add phpstan.
- Remove unused code, clarify mergeDeepArray difference from Drupal.

.editorconfig

@@ -0,0 +1,3 @@
+[*]
+indent_style = space
+indent_size=2

.gitignore

@@ -1,4 +1,5 @@
-/.idea/$*
-/.idea/workspace.xml
+/.idea/
+/.phpunit.cache
 /composer.lock
+/coverage
 /vendor/

README.md

@@ -1,13 +1,18 @@
 # drupal_composer__builder
 
-## Third party code
-
-Due to instabilities in the Composer plugin system, the plugin embeds a copy
-of the Drupal 8 NestedArray class. See src/NestedArray.php for details about the
-Composer issue and its equivalent in other products.
-
 ## License
 
 The plugin is licensed under the General Public License version 2.0 or later,
 just like the Drupal code it embeds.
 
+## Changes
+
+- 0.1.3 
+  - `mergeDeepArray` moved from `NestedArray` to `MergeParamsCommand` to
+    avoid confusion with the Drupal version.
+  - first unit test
+- 0.1.2
+  - commands can now use configurable templates defined in `composer.json`
+  - new `BuildServicesCommand` to build the `services.yml` file.
+- 0.1.1
+  - first actual release

composer.json

@@ -10,6 +10,12 @@
       "Fgm\\Drupal\\Composer\\": "src/"
     }
   },
+  "config": {
+    "bin-dir": "vendor/bin",
+    "discard-changes": true,
+    "optimize-autoloader": true,
+    "sort-packages": true
+  },
   "description": "A Composer plugin to help build Drupal sites",
   "extra": {
     "class": "Fgm\\Drupal\\Composer\\Builder"
@@ -17,17 +23,31 @@
   "license": "GPL-2.0-or-later",
   "minimum-stability": "dev",
   "name": "fgm/drupal_composer_builder",
+  "prefer-stable": true,
   "require": {
     "composer-plugin-api": "^1.1",
     "composer/installers": "^1.2"
   },
-  "type": "composer-plugin",
   "require-dev": {
-    "squizlabs/php_codesniffer": "^3.0@dev",
+    "composer/composer": "^1",
     "dealerdirect/phpcodesniffer-composer-installer": "dev-master",
-    "drupal/coder": "^8.3.6"
+    "drupal/coder": "^8.3.6",
+    "phpstan/phpstan": "^0.12.99",
+    "phpunit/phpunit": "^9.5",
+    "squizlabs/php_codesniffer": "^3.0@dev",
+    "twig/twig": "^1"
   },
   "scripts": {
-    "cs": "phpcs --standard=PSR1,Drupal -v src"
-  }
+    "check": [
+      "@cs",
+      "@stan",
+      "@test",
+      "@cover"
+    ],
+    "cover": "phpunit --coverage-filter=src --coverage-html=coverage --coverage-text",
+    "cs": "phpcs --standard=PSR1,Drupal -v src",
+    "stan": "phpstan analyse --level 5 src tests",
+    "test": "phpunit tests"
+  },
+  "type": "composer-plugin"
 }

phpunit.xml

@@ -0,0 +1,33 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:noNamespaceSchemaLocation="vendor/phpunit/phpunit/phpunit.xsd"
+         colors="true"
+         verbose="true"
+         cacheResultFile=".phpunit.cache/test-results"
+         failOnRisky="true"
+         failOnWarning="true">
+  <testsuites>
+    <testsuite name="unit">
+      <directory>tests</directory>
+    </testsuite>
+  </testsuites>
+
+  <coverage cacheDirectory=".phpunit.cache/code-coverage"
+            processUncoveredFiles="true"
+            ignoreDeprecatedCodeUnits="true">
+    <include>
+      <directory suffix=".php">src</directory>
+    </include>
+
+    <exclude>
+      <directory>vendor</directory>
+    </exclude>
+  </coverage>
+
+  <php>
+    <ini name="precision" value="14"/>
+    <ini name="serialize_precision" value="14"/>
+
+    <const name="PHPUNIT_TESTSUITE" value="true"/>
+  </php>
+</phpunit>

src/BaseBuilderCommand.php

@@ -44,12 +44,18 @@ abstract class BaseBuilderCommand extends BaseCommand {
    *   Command input.
    * @param \Symfony\Component\Console\Output\OutputInterface $output
    *   Command output.
+   * @param string $buildName
+   *   The nature of the build: services, settings, etc.
    *
    * @return array
    *   - string Template name
    *   - int Error
    */
-  public function validateTemplateName(InputInterface $input, OutputInterface $output, string $buildName): array {
+  public function validateTemplateName(
+    InputInterface $input,
+    OutputInterface $output,
+    string $buildName
+  ): array {
     $conf = $this->getComposer()->getPackage()->getExtra()[Builder::NAME] ?? [];
     $templateName = $conf['templates'][$buildName] ?? '';
     if (empty($templateName)) {
@@ -117,7 +123,11 @@ abstract class BaseBuilderCommand extends BaseCommand {
    * @throws \Twig\Error\RuntimeError
    * @throws \Twig\Error\SyntaxError
    */
-  protected function prepare(InputInterface $input, OutputInterface $output, string $buildName): array {
+  protected function prepare(
+    InputInterface $input,
+    OutputInterface $output,
+    string $buildName
+  ): array {
     [
       $templateName,
       $err,
@@ -163,7 +173,7 @@ abstract class BaseBuilderCommand extends BaseCommand {
    *   - string: error message
    *   - int: error, 0 if OK. If non-zero, only the error message is reliable.
    */
-  public function getParams() {
+  public function getParams(): array {
     $settingsPath = $this->getSettingsPath();
     $paramsPath = "${settingsPath}/merged.params.local.yml";
     $realParamsPath = realpath($paramsPath);

src/BuildServicesCommand.php

@@ -30,10 +30,6 @@ class BuildServicesCommand extends BaseBuilderCommand {
    */
   protected $eventName;
 
-  protected function UseTemplate() {
-    return FALSE;
-  }
-
   /**
    * Configures the current command.
    */
@@ -89,14 +85,14 @@ EOT
       if (file_exists($destination)) {
         $ok = unlink($destination);
         if (!$ok) {
-          return [sprintf("Could not remove old %s file", $destination), 1];
+          return 1;
         }
       }
       // Convert PHP array to Yaml.
       $yamlServices = Yaml::dump($services, 4, 2);
       $ok = file_put_contents($destination, $yamlServices, LOCK_EX);
       if (!$ok) {
-        return [sprintf('Could not write new %s file', $destination), 2];
+        return 2;
       }
     }
 

src/BuildSettingsCommand.php

@@ -65,10 +65,10 @@ EOT
 
     foreach ($params['sites'] as $name => $siteParams) {
       foreach (['build', 'run'] as $stage) {
-        $stageSettings = NestedArray::mergeDeepArray([
+        $stageSettings = MergeParamsCommand::mergeDeepArray([
           $siteParams['settings']['both'] ?? [],
           $siteParams['settings'][$stage] ?? [],
-        ], TRUE);
+        ]);
         $stageParams = $siteParams;
         $stageParams['settings'] = $stageSettings;
         $context = [

src/MergeParamsCommand.php

@@ -62,14 +62,14 @@ EOT
     }
 
     // Merge local into defaults.
-    $merged = NestedArray::mergeDeepArray([$dist, $local], TRUE);
+    $merged = static::mergeDeepArray([$dist, $local]);
 
     // Generate per-site data from settings/_default.
     $default = $merged['sites'][static::DEFAULT_SITE] ?? [];
     $sites = array_diff_key($merged['sites'], [static::DEFAULT_SITE => NULL]);
     $merged['sites'] = [];
     foreach ($sites as $name => $params) {
-      $merged['sites'][$name] = NestedArray::mergeDeep($default, $params);
+      $merged['sites'][$name] = static::mergeDeepArray([$default, $params]);
     }
     return $merged;
   }
@@ -115,6 +115,58 @@ EOT
       $output->writeln("Failed to write merged params.");
       return 2;
     }
+
+    return 0;
+  }
+
+  /**
+   * Merges multiple arrays, recursively, and returns the merged array.
+   *
+   * Only keyed arrays are merged recursively, indexed arrays are not merged :
+   * the deepest array replace the less deep array. This is unlike the original
+   * function introduced in Drupal 8.x, from which this derives.
+   *
+   * @param array $arrays
+   *   An arrays of arrays to merge.
+   *
+   * @return array
+   *   The merged array.
+   *
+   * @see \Fgm\Drupal\Composer\MergeParamsCommandTest::testMergeDeepArray()
+   */
+  public static function mergeDeepArray(array $arrays) {
+
+    $result = [];
+    foreach ($arrays as $array) {
+      foreach ($array as $key => $value) {
+        // Remove keys having NULL value to allow deletion of key previously
+        // defined.
+        if ($value === NULL) {
+          unset($result[$key]);
+          continue;
+        }
+        // Renumber integer keys as array_merge_recursive() does. Note that
+        // PHP automatically converts array keys that are integer strings
+        // (e.g., '1') to integers.
+        if (is_int($key)) {
+          // When an indexed array is overrided, the new values replace
+          // all overrided values (no merge).
+          if ($key === 0) {
+            $result = [];
+          }
+          $result[] = $value;
+        }
+        // Recurse when both values are arrays.
+        elseif (isset($result[$key]) && is_array($result[$key]) && is_array($value)) {
+          $result[$key] = static::mergeDeepArray([$result[$key], $value]);
+        }
+        // Otherwise, use the latter value, overriding any previous value.
+        else {
+          $result[$key] = $value;
+        }
+      }
+    }
+    return $result;
   }
 
 }

src/NestedArray.php

@@ -1,381 +0,0 @@
-<?php
-
-// @codingStandardsIgnoreFile
-
-/**
- * @file
- * This is a copy of <Drupal 8.8>/core/lib/Drupal/Component/Utility/NestedArray.php
- *
- * It used to be autoloaded from a drupal/core-utility dependency, but in some
- * configurations, this triggers a Composer bug similar to:
- *  - https://github.com/wikimedia/composer-merge-plugin/issues/139
- *  - https://github.com/composer/installers/issues/427
- */
-
-namespace Fgm\Drupal\Composer;
-
-/**
- * Provides helpers to perform operations on nested arrays and array keys of variable depth.
- *
- * @ingroup utility
- */
-class NestedArray {
-
-  /**
-   * Retrieves a value from a nested array with variable depth.
-   *
-   * This helper function should be used when the depth of the array element
-   * being retrieved may vary (that is, the number of parent keys is variable).
-   * It is primarily used for form structures and renderable arrays.
-   *
-   * Without this helper function the only way to get a nested array value with
-   * variable depth in one line would be using eval(), which should be avoided:
-   * @code
-   * // Do not do this! Avoid eval().
-   * // May also throw a PHP notice, if the variable array keys do not exist.
-   * eval('$value = $array[\'' . implode("']['", $parents) . "'];");
-   * @endcode
-   *
-   * Instead, use this helper function:
-   * @code
-   * $value = NestedArray::getValue($form, $parents);
-   * @endcode
-   *
-   * A return value of NULL is ambiguous, and can mean either that the requested
-   * key does not exist, or that the actual value is NULL. If it is required to
-   * know whether the nested array key actually exists, pass a third argument
-   * that is altered by reference:
-   * @code
-   * $key_exists = NULL;
-   * $value = NestedArray::getValue($form, $parents, $key_exists);
-   * if ($key_exists) {
-   *   // Do something with $value.
-   * }
-   * @endcode
-   *
-   * However if the number of array parent keys is static, the value should
-   * always be retrieved directly rather than calling this function.
-   * For instance:
-   * @code
-   * $value = $form['signature_settings']['signature'];
-   * @endcode
-   *
-   * @param array $array
-   *   The array from which to get the value.
-   * @param array $parents
-   *   An array of parent keys of the value, starting with the outermost key.
-   * @param bool $key_exists
-   *   (optional) If given, an already defined variable that is altered by
-   *   reference.
-   *
-   * @return mixed
-   *   The requested nested value. Possibly NULL if the value is NULL or not all
-   *   nested parent keys exist. $key_exists is altered by reference and is a
-   *   Boolean that indicates whether all nested parent keys exist (TRUE) or not
-   *   (FALSE). This allows to distinguish between the two possibilities when
-   *   NULL is returned.
-   *
-   * @see NestedArray::setValue()
-   * @see NestedArray::unsetValue()
-   */
-  public static function &getValue(array &$array, array $parents, &$key_exists = NULL) {
-    $ref = &$array;
-    foreach ($parents as $parent) {
-      if (is_array($ref) && (isset($ref[$parent]) || array_key_exists($parent, $ref))) {
-        $ref = &$ref[$parent];
-      }
-      else {
-        $key_exists = FALSE;
-        $null = NULL;
-        return $null;
-      }
-    }
-    $key_exists = TRUE;
-    return $ref;
-  }
-
-  /**
-   * Sets a value in a nested array with variable depth.
-   *
-   * This helper function should be used when the depth of the array element you
-   * are changing may vary (that is, the number of parent keys is variable). It
-   * is primarily used for form structures and renderable arrays.
-   *
-   * Example:
-   * @code
-   * // Assume you have a 'signature' element somewhere in a form. It might be:
-   * $form['signature_settings']['signature'] = array(
-   *   '#type' => 'text_format',
-   *   '#title' => t('Signature'),
-   * );
-   * // Or, it might be further nested:
-   * $form['signature_settings']['user']['signature'] = array(
-   *   '#type' => 'text_format',
-   *   '#title' => t('Signature'),
-   * );
-   * @endcode
-   *
-   * To deal with the situation, the code needs to figure out the route to the
-   * element, given an array of parents that is either
-   * @code array('signature_settings', 'signature') @endcode
-   * in the first case or
-   * @code array('signature_settings', 'user', 'signature') @endcode
-   * in the second case.
-   *
-   * Without this helper function the only way to set the signature element in
-   * one line would be using eval(), which should be avoided:
-   * @code
-   * // Do not do this! Avoid eval().
-   * eval('$form[\'' . implode("']['", $parents) . '\'] = $element;');
-   * @endcode
-   *
-   * Instead, use this helper function:
-   * @code
-   * NestedArray::setValue($form, $parents, $element);
-   * @endcode
-   *
-   * However if the number of array parent keys is static, the value should
-   * always be set directly rather than calling this function. For instance,
-   * for the first example we could just do:
-   * @code
-   * $form['signature_settings']['signature'] = $element;
-   * @endcode
-   *
-   * @param array $array
-   *   A reference to the array to modify.
-   * @param array $parents
-   *   An array of parent keys, starting with the outermost key.
-   * @param mixed $value
-   *   The value to set.
-   * @param bool $force
-   *   (optional) If TRUE, the value is forced into the structure even if it
-   *   requires the deletion of an already existing non-array parent value. If
-   *   FALSE, PHP throws an error if trying to add into a value that is not an
-   *   array. Defaults to FALSE.
-   *
-   * @see NestedArray::unsetValue()
-   * @see NestedArray::getValue()
-   */
-  public static function setValue(array &$array, array $parents, $value, $force = FALSE) {
-    $ref = &$array;
-    foreach ($parents as $parent) {
-      // PHP auto-creates container arrays and NULL entries without error if $ref
-      // is NULL, but throws an error if $ref is set, but not an array.
-      if ($force && isset($ref) && !is_array($ref)) {
-        $ref = [];
-      }
-      $ref = &$ref[$parent];
-    }
-    $ref = $value;
-  }
-
-  /**
-   * Unsets a value in a nested array with variable depth.
-   *
-   * This helper function should be used when the depth of the array element you
-   * are changing may vary (that is, the number of parent keys is variable). It
-   * is primarily used for form structures and renderable arrays.
-   *
-   * Example:
-   * @code
-   * // Assume you have a 'signature' element somewhere in a form. It might be:
-   * $form['signature_settings']['signature'] = array(
-   *   '#type' => 'text_format',
-   *   '#title' => t('Signature'),
-   * );
-   * // Or, it might be further nested:
-   * $form['signature_settings']['user']['signature'] = array(
-   *   '#type' => 'text_format',
-   *   '#title' => t('Signature'),
-   * );
-   * @endcode
-   *
-   * To deal with the situation, the code needs to figure out the route to the
-   * element, given an array of parents that is either
-   * @code array('signature_settings', 'signature') @endcode
-   * in the first case or
-   * @code array('signature_settings', 'user', 'signature') @endcode
-   * in the second case.
-   *
-   * Without this helper function the only way to unset the signature element in
-   * one line would be using eval(), which should be avoided:
-   * @code
-   * // Do not do this! Avoid eval().
-   * eval('unset($form[\'' . implode("']['", $parents) . '\']);');
-   * @endcode
-   *
-   * Instead, use this helper function:
-   * @code
-   * NestedArray::unset_nested_value($form, $parents, $element);
-   * @endcode
-   *
-   * However if the number of array parent keys is static, the value should
-   * always be set directly rather than calling this function. For instance, for
-   * the first example we could just do:
-   * @code
-   * unset($form['signature_settings']['signature']);
-   * @endcode
-   *
-   * @param array $array
-   *   A reference to the array to modify.
-   * @param array $parents
-   *   An array of parent keys, starting with the outermost key and including
-   *   the key to be unset.
-   * @param bool $key_existed
-   *   (optional) If given, an already defined variable that is altered by
-   *   reference.
-   *
-   * @see NestedArray::setValue()
-   * @see NestedArray::getValue()
-   */
-  public static function unsetValue(array &$array, array $parents, &$key_existed = NULL) {
-    $unset_key = array_pop($parents);
-    $ref = &self::getValue($array, $parents, $key_existed);
-    if ($key_existed && is_array($ref) && (isset($ref[$unset_key]) || array_key_exists($unset_key, $ref))) {
-      $key_existed = TRUE;
-      unset($ref[$unset_key]);
-    }
-    else {
-      $key_existed = FALSE;
-    }
-  }
-
-  /**
-   * Determines whether a nested array contains the requested keys.
-   *
-   * This helper function should be used when the depth of the array element to
-   * be checked may vary (that is, the number of parent keys is variable). See
-   * NestedArray::setValue() for details. It is primarily used for form
-   * structures and renderable arrays.
-   *
-   * If it is required to also get the value of the checked nested key, use
-   * NestedArray::getValue() instead.
-   *
-   * If the number of array parent keys is static, this helper function is
-   * unnecessary and the following code can be used instead:
-   * @code
-   * $value_exists = isset($form['signature_settings']['signature']);
-   * $key_exists = array_key_exists('signature', $form['signature_settings']);
-   * @endcode
-   *
-   * @param array $array
-   *   The array with the value to check for.
-   * @param array $parents
-   *   An array of parent keys of the value, starting with the outermost key.
-   *
-   * @return bool
-   *   TRUE if all the parent keys exist, FALSE otherwise.
-   *
-   * @see NestedArray::getValue()
-   */
-  public static function keyExists(array $array, array $parents) {
-    // Although this function is similar to PHP's array_key_exists(), its
-    // arguments should be consistent with getValue().
-    $key_exists = NULL;
-    self::getValue($array, $parents, $key_exists);
-    return $key_exists;
-  }
-
-  /**
-   * Merges multiple arrays, recursively, and returns the merged array.
-   *
-   * This function is similar to PHP's array_merge_recursive() function, but it
-   * handles non-array values differently. When merging values that are not both
-   * arrays, the latter value replaces the former rather than merging with it.
-   *
-   * Example:
-   * @code
-   * $link_options_1 = array('fragment' => 'x', 'attributes' => array('title' => t('X'), 'class' => array('a', 'b')));
-   * $link_options_2 = array('fragment' => 'y', 'attributes' => array('title' => t('Y'), 'class' => array('c', 'd')));
-   *
-   * // This results in array('fragment' => array('x', 'y'), 'attributes' => array('title' => array(t('X'), t('Y')), 'class' => array('a', 'b', 'c', 'd'))).
-   * $incorrect = array_merge_recursive($link_options_1, $link_options_2);
-   *
-   * // This results in array('fragment' => 'y', 'attributes' => array('title' => t('Y'), 'class' => array('a', 'b', 'c', 'd'))).
-   * $correct = NestedArray::mergeDeep($link_options_1, $link_options_2);
-   * @endcode
-   *
-   * @param array ...
-   *   Arrays to merge.
-   *
-   * @return array
-   *   The merged array.
-   *
-   * @see NestedArray::mergeDeepArray()
-   */
-  public static function mergeDeep() {
-    return self::mergeDeepArray(func_get_args());
-  }
-
-  /**
-   * Merges multiple arrays, recursively, and returns the merged array.
-   *
-   * This function is equivalent to NestedArray::mergeDeep(), except the
-   * input arrays are passed as a single array parameter rather than a variable
-   * parameter list.
-   *
-   * The following are equivalent:
-   * - NestedArray::mergeDeep($a, $b);
-   * - NestedArray::mergeDeepArray(array($a, $b));
-   *
-   * The following are also equivalent:
-   * - call_user_func_array('NestedArray::mergeDeep', $arrays_to_merge);
-   * - NestedArray::mergeDeepArray($arrays_to_merge);
-   *
-   * @param array $arrays
-   *   An arrays of arrays to merge.
-   * @param bool $preserve_integer_keys
-   *   (optional) If given, integer keys will be preserved and merged instead of
-   *   appended. Defaults to FALSE.
-   *
-   * @return array
-   *   The merged array.
-   *
-   * @see NestedArray::mergeDeep()
-   */
-  public static function mergeDeepArray(array $arrays, $preserve_integer_keys = FALSE) {
-    $result = [];
-    foreach ($arrays as $array) {
-      foreach ($array as $key => $value) {
-        // Renumber integer keys as array_merge_recursive() does unless
-        // $preserve_integer_keys is set to TRUE. Note that PHP automatically
-        // converts array keys that are integer strings (e.g., '1') to integers.
-        if (is_int($key) && !$preserve_integer_keys) {
-          $result[] = $value;
-        }
-        // Recurse when both values are arrays.
-        elseif (isset($result[$key]) && is_array($result[$key]) && is_array($value)) {
-          $result[$key] = self::mergeDeepArray([$result[$key], $value], $preserve_integer_keys);
-        }
-        // Otherwise, use the latter value, overriding any previous value.
-        else {
-          $result[$key] = $value;
-        }
-      }
-    }
-    return $result;
-  }
-
-  /**
-   * Filters a nested array recursively.
-   *
-   * @param array $array
-   *   The filtered nested array.
-   * @param callable|null $callable
-   *   The callable to apply for filtering.
-   *
-   * @return array
-   *   The filtered array.
-   */
-  public static function filter(array $array, callable $callable = NULL) {
-    $array = is_callable($callable) ? array_filter($array, $callable) : array_filter($array);
-    foreach ($array as &$element) {
-      if (is_array($element)) {
-        $element = static::filter($element, $callable);
-      }
-    }
-
-    return $array;
-  }
-
-}

src/PhpMemcacheAdminConfigCommand.php

@@ -4,8 +4,7 @@ declare(strict_types=1);
 
 namespace Fgm\Drupal\Composer;
 
-use Composer\Package\CompletePackageInterface;
-use Osinet\Deploy\BuilderBase;
+use Composer\Package\PackageInterface;
 use Symfony\Component\Console\Input\InputArgument;
 use Symfony\Component\Console\Input\InputDefinition;
 use Symfony\Component\Console\Input\InputInterface;
@@ -125,8 +124,8 @@ EOT
     $variables = array_merge(
       $params[static::BUILD_NAME]['basic'],
       $params[static::BUILD_NAME]['advanced'], [
-      'servers' => $params['memcache']['servers'],
-    ],
+        'servers' => $params['memcache']['servers'],
+      ],
       ['local_params_path' => realpath($this->getSettingsPath() . "/params.local.yml")]
     );
     return $variables;
@@ -144,7 +143,7 @@ EOT
       ->getRepositoryManager()
       ->getLocalRepository()
       ->getPackages();
-    $package = current(array_filter($packages, function (CompletePackageInterface $package) {
+    $package = current(array_filter($packages, function (PackageInterface $package) {
       return $package->getName() === static::PACKAGE;
     }));
     $targetBase = $composer

tests/MergeParamsCommandTest.php

@@ -0,0 +1,70 @@
+<?php
+declare(strict_types=1);
+
+namespace Fgm\Drupal\Composer;
+
+use PHPUnit\Framework\TestCase;
+
+final class MergeParamsCommandTest extends TestCase {
+
+  /**
+   * Test MergeParamsCommand::merge().
+   *
+   * @covers \Fgm\Drupal\Composer\MergeParamsCommand::mergeDeepArray
+   */
+  public function testMergeDeepArray() {
+    // Base array (like a dist.params.local.yml).
+    $dist = [
+      'keyedArray1' => [
+        'key1' => 'dist1',
+        'key2' => 'dist2',
+        'key3' => 'dist3',
+      ],
+      'indexedArray1' => [
+        'dist1',
+        'dist2',
+        'dist3',
+      ],
+    ];
+    // Overriding array (like params.local.yml).
+    $local = [
+      'keyedArray1' => [
+        'key1' => 'local1',
+        'key3' => NULL,
+        'key4' => 'local4',
+      ],
+      'keyedArray2' => [
+        'key1' => 'local1',
+      ],
+      'indexedArray1' => [
+        'local1',
+        'local2',
+      ],
+    ];
+    // Merged array (like merged.params.local.yml).
+    $merged = MergeParamsCommand::mergeDeepArray([$dist, $local]);
+    $expected = [
+      'keyedArray1' => [
+        // Key1 : Dist value is overrided by local value.
+        'key1' => 'local1',
+        // Key2 : No overriding in local, dist value is transmitted.
+        'key2' => 'dist2',
+        // Key3 : Dist value is overrided with a NULL value: key3 is removed.
+        // Key4 : No key4 in dist array, local Key4 is added.
+        'key4' => 'local4',
+      ],
+      // No Array2 in dist, local Array2 is added.
+      'keyedArray2' => [
+        'key1' => 'local1',
+      ],
+      // Dist indexed array is replaced by local index array.
+      'indexedArray1' => [
+        'local1',
+        'local2',
+      ],
+    ];
+
+    $this->assertEquals($expected, $merged);
+  }
+
+}