diff --git a/tests/Client/InsertTest.php b/tests/Client/InsertTest.php
index e54fa43..f204509 100644
--- a/tests/Client/InsertTest.php
+++ b/tests/Client/InsertTest.php
@@ -33,11 +33,11 @@ public function testInsert(string $tableSql): void
             ['PageViews' => 6, 'UserID' => 4324182021466249494, 'Duration' => 185, 'Sign' => 1],
         ];
 
-        $this->client->executeQuery($tableSql);
+        self::$client->executeQuery($tableSql);
 
-        $this->client->insert('UserActivity', $data);
+        self::$client->insert('UserActivity', $data);
 
-        $output = $this->client->select(
+        $output = self::$client->select(
             <<<'CLICKHOUSE'
 SELECT * FROM UserActivity
 CLICKHOUSE,
@@ -57,9 +57,9 @@ public function testInsertUseColumns(string $tableSql): void
             ['PageViews' => 6, 'UserID' => '4324182021466249494', 'Duration' => 185, 'Sign' => 1],
         ];
 
-        $this->client->executeQuery($tableSql);
+        self::$client->executeQuery($tableSql);
 
-        $this->client->insert(
+        self::$client->insert(
             'UserActivity',
             [
                 [5, 4324182021466249494, 146, -1],
@@ -68,7 +68,7 @@ public function testInsertUseColumns(string $tableSql): void
             ['PageViews', 'UserID', 'Duration', 'Sign'],
         );
 
-        $output = $this->client->select(
+        $output = self::$client->select(
             <<<'CLICKHOUSE'
 SELECT * FROM UserActivity
 CLICKHOUSE,
@@ -80,7 +80,7 @@ public function testInsertUseColumns(string $tableSql): void
 
     public function testInsertEscaping(): void
     {
-        $this->client->executeQuery(
+        self::$client->executeQuery(
             <<<'CLICKHOUSE'
 CREATE TABLE a (
     b  Nullable(String)
@@ -94,9 +94,9 @@ public function testInsertEscaping(): void
             ["\t"],
         ];
 
-        $this->client->insert('a', $expectedData);
+        self::$client->insert('a', $expectedData);
 
-        $output = $this->client->select(
+        $output = self::$client->select(
             <<<'CLICKHOUSE'
 SELECT * FROM a
 CLICKHOUSE,
@@ -124,7 +124,7 @@ public static function providerInsert(): iterable
 
     public function testInsertWithFormat(): void
     {
-        $this->client->executeQuery(
+        self::$client->executeQuery(
             <<<'CLICKHOUSE'
 CREATE TABLE UserActivity (
     PageViews   UInt32,
@@ -136,7 +136,7 @@ public function testInsertWithFormat(): void
 CLICKHOUSE,
         );
 
-        $this->client->insertWithFormat(
+        self::$client->insertWithFormat(
             'UserActivity',
             new JsonEachRow(),
             <<<'JSONEACHROW'
@@ -145,7 +145,7 @@ public function testInsertWithFormat(): void
 JSONEACHROW,
         );
 
-        $output = $this->client->select(
+        $output = self::$client->select(
             <<<'CLICKHOUSE'
 SELECT * FROM UserActivity
 CLICKHOUSE
@@ -166,13 +166,13 @@ public function testInsertEmptyValuesThrowsException(): void
     {
         $this->expectException(CannotInsert::class);
 
-        $this->client->insert('table', []);
+        self::$client->insert('table', []);
     }
 
     public function testInsertToNonExistentTableExpectServerError(): void
     {
         $this->expectException(ServerError::class);
 
-        $this->client->insert('table', [[1]]);
+        self::$client->insert('table', [[1]]);
     }
 }
diff --git a/tests/Client/SelectTest.php b/tests/Client/SelectTest.php
index e0bea1e..7de844a 100644
--- a/tests/Client/SelectTest.php
+++ b/tests/Client/SelectTest.php
@@ -34,7 +34,7 @@ final class SelectTest extends TestCaseBase
 
     public function testSelectWithParams(): void
     {
-        $client = $this->client;
+        $client = self::$client;
         $output = $client->selectWithParams('SELECT {p1:UInt8} AS data', ['p1' => 3], new TabSeparated());
 
         self::assertSame("3\n", $output->contents);
@@ -43,7 +43,7 @@ public function testSelectWithParams(): void
     #[DataProvider('providerJson')]
     public function testJson(mixed $expectedData, string $sql): void
     {
-        $client = $this->client;
+        $client = self::$client;
         $output = $client->select($sql, new Json());
 
         self::assertSame($expectedData, $output->data);
@@ -82,7 +82,7 @@ public static function providerJson(): iterable
     #[DataProvider('providerJsonCompact')]
     public function testJsonCompact(mixed $expectedData, string $sql): void
     {
-        $client = $this->client;
+        $client = self::$client;
         $output = $client->select($sql, new JsonCompact());
 
         self::assertSame($expectedData, $output->data);
@@ -121,7 +121,7 @@ public static function providerJsonCompact(): iterable
     #[DataProvider('providerJsonEachRow')]
     public function testJsonEachRow(mixed $expectedData, string $sql): void
     {
-        $client = $this->client;
+        $client = self::$client;
         $output = $client->select($sql, new JsonEachRow());
 
         self::assertSame($expectedData, $output->data);
@@ -159,7 +159,7 @@ public static function providerJsonEachRow(): iterable
 
     public function testNull(): void
     {
-        $client = $this->client;
+        $client = self::$client;
         $client->select('SELECT 1', new Null_());
 
         self::assertTrue(true);
@@ -170,6 +170,6 @@ public function testSettingsArePassed(): void
         self::expectException(ServerError::class);
         $this->expectExceptionMessageMatches("~DB::Exception: Database `non-existent` (doesn't|does not) exist~");
 
-        $this->client->select('SELECT 1', new JsonCompact(), ['database' => 'non-existent']);
+        self::$client->select('SELECT 1', new JsonCompact(), ['database' => 'non-existent']);
     }
 }
diff --git a/tests/Snippet/CurrentDatabaseTest.php b/tests/Snippet/CurrentDatabaseTest.php
index 417959e..4a2f198 100644
--- a/tests/Snippet/CurrentDatabaseTest.php
+++ b/tests/Snippet/CurrentDatabaseTest.php
@@ -18,7 +18,7 @@ public function testRun(): void
     {
         self::assertSame(
             $this->currentDbName,
-            CurrentDatabase::run($this->client),
+            CurrentDatabase::run(self::$client),
         );
     }
 }
diff --git a/tests/Snippet/DatabaseSizeTest.php b/tests/Snippet/DatabaseSizeTest.php
index 1bc1e66..f779a22 100644
--- a/tests/Snippet/DatabaseSizeTest.php
+++ b/tests/Snippet/DatabaseSizeTest.php
@@ -18,7 +18,7 @@ final class DatabaseSizeTest extends TestCaseBase
 
     public function setUp(): void
     {
-        $this->client->executeQuery(
+        self::$client->executeQuery(
             <<<'CLICKHOUSE'
 CREATE TABLE test (
     a_date  DateTime,
@@ -33,9 +33,9 @@ public function setUp(): void
 
     public function testRun(): void
     {
-        self::assertSame(0, DatabaseSize::run($this->client));
+        self::assertSame(0, DatabaseSize::run(self::$client));
 
-        $this->client->insert('test', [[new DateTimeImmutable('2020-08-01 00:11:22'), 1]]);
+        self::$client->insert('test', [[new DateTimeImmutable('2020-08-01 00:11:22'), 1]]);
 
         if (ClickHouseVersion::get() >= 2307) {
             $expectedSize = 316;
@@ -45,11 +45,11 @@ public function testRun(): void
             $expectedSize = 150;
         }
 
-        self::assertSame($expectedSize, DatabaseSize::run($this->client));
+        self::assertSame($expectedSize, DatabaseSize::run(self::$client));
     }
 
     public function tearDown(): void
     {
-        $this->client->executeQuery('DROP TABLE test');
+        self::$client->executeQuery('DROP TABLE test');
     }
 }
diff --git a/tests/Snippet/PartsTest.php b/tests/Snippet/PartsTest.php
index 24bbb0b..0232430 100644
--- a/tests/Snippet/PartsTest.php
+++ b/tests/Snippet/PartsTest.php
@@ -16,6 +16,6 @@ final class PartsTest extends TestCaseBase
 
     public function testRun(): void
     {
-        self::assertSame([], Parts::run($this->client, 'system.query_log'));
+        self::assertSame([], Parts::run(self::$client, 'system.query_log'));
     }
 }
diff --git a/tests/Snippet/ShowCreateTableTest.php b/tests/Snippet/ShowCreateTableTest.php
index fa1f3ca..70c7680 100644
--- a/tests/Snippet/ShowCreateTableTest.php
+++ b/tests/Snippet/ShowCreateTableTest.php
@@ -24,9 +24,9 @@ public function testRun(): void
 CREATE TABLE $dbName.test (`date` Date) ENGINE = Memory
 CLICKHOUSE;
 
-        $this->client->executeQuery($sql);
+        self::$client->executeQuery($sql);
 
-        $createTableSql = ShowCreateTable::run($this->client, 'test');
+        $createTableSql = ShowCreateTable::run(self::$client, 'test');
 
         // BC
         $createTableSql = str_replace(
diff --git a/tests/Snippet/ShowDatabasesTest.php b/tests/Snippet/ShowDatabasesTest.php
index 9456245..d486a2f 100644
--- a/tests/Snippet/ShowDatabasesTest.php
+++ b/tests/Snippet/ShowDatabasesTest.php
@@ -23,7 +23,7 @@ final class ShowDatabasesTest extends TestCaseBase
 
     public function testRun(): void
     {
-        $databases = ShowDatabases::run($this->client);
+        $databases = ShowDatabases::run(self::$client);
         self::assertGreaterThan(2, count($databases)); // Default, system, at least one test database
 
         $databases = array_filter(
diff --git a/tests/Snippet/TableSizesTest.php b/tests/Snippet/TableSizesTest.php
index 6e7e92b..16214c4 100644
--- a/tests/Snippet/TableSizesTest.php
+++ b/tests/Snippet/TableSizesTest.php
@@ -17,7 +17,7 @@ final class TableSizesTest extends TestCaseBase
 
     public function setUp(): void
     {
-        $this->client->executeQuery(
+        self::$client->executeQuery(
             <<<'CLICKHOUSE'
 CREATE TABLE test (
     a_date  DateTime,
@@ -32,18 +32,18 @@ public function setUp(): void
 
     public function testRun(): void
     {
-        $this->client->insert('test', [[new DateTimeImmutable(), 1]]);
+        self::$client->insert('test', [[new DateTimeImmutable(), 1]]);
 
-        self::assertCount(1, TableSizes::run($this->client));
+        self::assertCount(1, TableSizes::run(self::$client));
     }
 
     public function testRunOnNonexistentDatabase(): void
     {
-        self::assertSame([], TableSizes::run($this->client, 'does not exist'));
+        self::assertSame([], TableSizes::run(self::$client, 'does not exist'));
     }
 
     public function tearDown(): void
     {
-        $this->client->executeQuery('DROP TABLE test');
+        self::$client->executeQuery('DROP TABLE test');
     }
 }
diff --git a/tests/Snippet/VersionTest.php b/tests/Snippet/VersionTest.php
index 205f870..f661c4a 100644
--- a/tests/Snippet/VersionTest.php
+++ b/tests/Snippet/VersionTest.php
@@ -16,6 +16,6 @@ final class VersionTest extends TestCaseBase
 
     public function testRun(): void
     {
-        self::assertMatchesRegularExpression('~(\d+\.)+\d+~', Version::run($this->client));
+        self::assertMatchesRegularExpression('~(\d+\.)+\d+~', Version::run(self::$client));
     }
 }