added test to change decimal precision in pgsql

tests/Doctrine/Tests/DBAL/Platforms/PostgreSqlPlatformTest.php

@@ -314,5 +314,52 @@ class PostgreSqlPlatformTest extends AbstractPlatformTestCase
         $this->assertEquals('1', $platform->convertBooleans(true));
         $this->assertEquals('0', $platform->convertBooleans(false));
     }
+
+    public function testAlterDecimalPrecisionScale()
+    {
+        $table = new Table('mytable');
+        $table->addColumn('dfoo1', 'decimal');
+        $table->addColumn('dfoo2', 'decimal', array('precision' => 10, 'scale' => 6));
+        $table->addColumn('dfoo3', 'decimal', array('precision' => 10, 'scale' => 6));
+        $table->addColumn('dfoo4', 'decimal', array('precision' => 10, 'scale' => 6));
+
+        $tableDiff = new TableDiff('mytable');
+        $tableDiff->fromTable = $table;
+
+        $tableDiff->changedColumns['dloo1'] = new \Doctrine\DBAL\Schema\ColumnDiff(
+            'dloo1', new \Doctrine\DBAL\Schema\Column(
+                'dloo1', \Doctrine\DBAL\Types\Type::getType('decimal'), array('precision' => 16, 'scale' => 6)
+            ),
+            array('type', 'notnull', 'default')
+        );
+        $tableDiff->changedColumns['dloo2'] = new \Doctrine\DBAL\Schema\ColumnDiff(
+            'dloo2', new \Doctrine\DBAL\Schema\Column(
+                'dloo2', \Doctrine\DBAL\Types\Type::getType('decimal'), array('precision' => 10, 'scale' => 4)
+            ),
+            array('type', 'notnull', 'default')
+        );
+        $tableDiff->changedColumns['dloo3'] = new \Doctrine\DBAL\Schema\ColumnDiff(
+            'dloo3', new \Doctrine\DBAL\Schema\Column(
+                'dloo3', \Doctrine\DBAL\Types\Type::getType('decimal'), array('precision' => 10, 'scale' => 6)
+            ),
+            array('type', 'notnull', 'default')
+        );
+        $tableDiff->changedColumns['dloo4'] = new \Doctrine\DBAL\Schema\ColumnDiff(
+            'dloo4', new \Doctrine\DBAL\Schema\Column(
+                'dloo4', \Doctrine\DBAL\Types\Type::getType('decimal'), array('precision' => 16, 'scale' => 8)
+            ),
+            array('type', 'notnull', 'default')
+        );
+
+        $sql = $this->_platform->getAlterTableSQL($tableDiff);
+
+        $expectedSql = array(
+            'ALTER TABLE mytable ALTER dloo1 TYPE NUMERIC(16, 6)',
+            'ALTER TABLE mytable ALTER dloo2 TYPE NUMERIC(10, 4)',
+            'ALTER TABLE mytable ALTER dloo4 TYPE NUMERIC(16, 8)',
+        );
+
+        $this->assertEquals($expectedSql, $sql);
+    }
 }