[3.x] Take fixture name into account for table key hash (#28)

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Co-authored-by: german.krutov <german.krutov@orca.ch>

src/TestSuite/Fixture/ChecksumTestFixture.php

@@ -114,10 +114,15 @@ protected function _hash(ConnectionInterface $connection): string
     /**
      * Get the key for table hashes
      *
-     * @return string key for specify connection and table
+     * The key contains:
+     * - The table name
+     * - The connection name to prevent collisions across connections
+     * - The fixture class name to prevent collisions when loading multiple fixtures for the same table throughout a test run
+     *
+     * @return string Key based on connection, table and fixture class names
      */
     protected function _getTableKey(): string
     {
-        return $this->connection() . '-' . $this->table;
+        return $this->connection() . '-' . $this->table . '-' . static::class;
     }
 }