MAGETWO-95259: CatalogSearch module deprecation must be reverted

- Deprecated all classes/interfaces in Magento\Framework\Search\Adapter\Mysql and added missing descriptions to avoid static tests failures.
- Deprecated MySQL search related unit tests (for easier removal in the future)
- Removed deprecation of Magento\CatalogSearch\Model\ResourceModel\FulltextCollection (it should be kept and refactored)

Author: paliarush

app/code/Magento/CatalogSearch/Model/ResourceModel/Fulltext/Collection.php

@@ -20,12 +20,12 @@
 
 /**
  * Fulltext Collection
- * @SuppressWarnings(PHPMD.CouplingBetweenObjects)
+ *
+ * This collection should be refactored to not have dependencies on MySQL-specific implementation.
  *
  * @api
  * @since 100.0.2
- * @deprecated
- * @see \Magento\ElasticSearch
+ * @SuppressWarnings(PHPMD.CouplingBetweenObjects)
  */
 class Collection extends \Magento\Catalog\Model\ResourceModel\Product\Collection
 {

app/code/Magento/CatalogSearch/Setup/Patch/Data/MySQLSearchDeprecationNotification.php

@@ -7,6 +7,12 @@
 
 namespace Magento\CatalogSearch\Setup\Patch\Data;
 
+/**
+ * Implementation of the notification about MySQL search being deprecated.
+ *
+ * @deprecated
+ * @see \Magento\ElasticSearch
+ */
 class MySQLSearchDeprecationNotification implements \Magento\Framework\Setup\Patch\DataPatchInterface
 {
     /**

app/code/Magento/CatalogSearch/Test/Unit/Model/Adapter/Mysql/Aggregation/DataProvider/QueryBuilderTest.php

@@ -20,6 +20,8 @@
  * Test for Magento\CatalogSearch\Model\Adapter\Mysql\Aggregation\DataProvider\QueryBuilder.
  *
  * @SuppressWarnings(PHPMD.CouplingBetweenObjects)
+ * @deprecated
+ * @see \Magento\ElasticSearch
  */
 class QueryBuilderTest extends \PHPUnit\Framework\TestCase
 {

app/code/Magento/CatalogSearch/Test/Unit/Model/Adapter/Mysql/Aggregation/DataProviderTest.php

@@ -23,6 +23,9 @@
 
 /**
  * @SuppressWarnings(PHPMD.CouplingBetweenObjects)
+ *
+ * @deprecated
+ * @see \Magento\ElasticSearch
  */
 class DataProviderTest extends \PHPUnit\Framework\TestCase
 {

app/code/Magento/CatalogSearch/Test/Unit/Model/Adapter/Mysql/Dynamic/DataProviderTest.php

@@ -19,8 +19,9 @@
 use Magento\Store\Model\StoreManager;
 
 /**
- * Class DataProviderTest
  * @SuppressWarnings(PHPMD.CouplingBetweenObjects)
+ * @deprecated
+ * @see \Magento\ElasticSearch
  */
 class DataProviderTest extends \PHPUnit\Framework\TestCase
 {

app/code/Magento/CatalogSearch/Test/Unit/Model/Adapter/Mysql/Field/ResolverTest.php

@@ -9,6 +9,9 @@
 
 /**
  * Unit tests for Magento\CatalogSearch\Model\Adapter\Mysql\Field\Resolver class.
+ *
+ * @deprecated
+ * @see \Magento\ElasticSearch
  */
 class ResolverTest extends \PHPUnit\Framework\TestCase
 {

app/code/Magento/CatalogSearch/Test/Unit/Model/Adapter/Mysql/Filter/AliasResolverTest.php

@@ -9,6 +9,10 @@
 use Magento\CatalogSearch\Model\Search\RequestGenerator;
 use Magento\Framework\TestFramework\Unit\Helper\ObjectManager as ObjectManagerHelper;
 
+/**
+ * @deprecated
+ * @see \Magento\ElasticSearch
+ */
 class AliasResolverTest extends \PHPUnit\Framework\TestCase
 {
     /**

app/code/Magento/CatalogSearch/Test/Unit/Model/Adapter/Mysql/Filter/PreprocessorTest.php

@@ -15,6 +15,8 @@
 
 /**
  * @SuppressWarnings(PHPMD.CouplingBetweenObjects)
+ * @deprecated
+ * @see \Magento\ElasticSearch
  */
 class PreprocessorTest extends \PHPUnit\Framework\TestCase
 {

app/code/Magento/CatalogSearch/Test/Unit/Model/ResourceModel/Advanced/CollectionTest.php

@@ -13,6 +13,8 @@
  * Tests Magento\CatalogSearch\Model\ResourceModel\Advanced\Collection
  *
  * @SuppressWarnings(PHPMD.CouplingBetweenObjects)
+ * @deprecated
+ * @see \Magento\ElasticSearch
  */
 class CollectionTest extends BaseCollection
 {

app/code/Magento/CatalogSearch/Test/Unit/Model/ResourceModel/BaseCollection.php

@@ -9,6 +9,9 @@
  * Base class for Collection tests.
  *
  * Contains helper methods to get commonly used mocks used for collection tests.
+ *
+ * @deprecated
+ * @see \Magento\ElasticSearch
  **/
 class BaseCollection extends \PHPUnit\Framework\TestCase
 {