Added tests. Fixed underscore usage in new classes for methods and properties

src/Schema/UniqueConstraint.php

@@ -48,7 +48,7 @@ class UniqueConstraint extends AbstractAsset implements Constraint
         $this->options = $options;
 
         foreach ($columns as $column) {
-            $this->_addColumn($column);
+            $this->addColumn($column);
         }
 
         foreach ($flags as $flag) {
@@ -167,7 +167,7 @@ class UniqueConstraint extends AbstractAsset implements Constraint
     /**
      * @return void
      */
-    protected function _addColumn(string $column)
+    protected function addColumn(string $column) : void
     {
         $this->columns[$column] = new Identifier($column);
     }

tests/Platforms/AbstractPlatformTestCase.php

@@ -823,6 +823,16 @@ abstract class AbstractPlatformTestCase extends TestCase
         self::assertFalse($this->platform->usesSequenceEmulatedIdentityColumns());
     }
 
+    public function testGetSequencePrefixWithoutSchema() : void
+    {
+        self::assertEquals("foo", $this->platform->getSequencePrefix("foo"));
+    }
+
+    public function testGetSequencePrefixWithSchema() : void
+    {
+        self::assertEquals("bar.foo", $this->platform->getSequencePrefix("foo", "bar"));
+    }
+
     /**
      * @group DBAL-563
      */

tests/Platforms/SqlitePlatformTest.php

@@ -824,4 +824,9 @@ class SqlitePlatformTest extends AbstractPlatformTestCase
             'Column "no_collation" will use the default collation (BINARY) and "column_collation" overwrites the collation on this column'
         );
     }
+
+    public function testGetSequencePrefixWithSchema() : void
+    {
+        self::assertEquals("bar__foo", $this->platform->getSequencePrefix("foo", "bar"));
+    }
 }