class DriverSpecificSchemaTestBase

abstract class DriverSpecificSchemaTestBase extends DriverSpecificKernelTestBase {
    use SchemaIntrospectionTestTrait;
    
    /**
     * Database schema instance.
     */
    protected Schema $schema;
    
    /**
     * A global counter for table and field creation.
     */
    protected int $counter = 0;
    
    /**
     * Connection to the database.
     */
    protected Connection $connection;
    
    /**
     * {@inheritdoc}
     */
    protected function setUp() : void {
        parent::setUp();
        $this->schema = $this->connection
            ->schema();
    }
    
    /**
     * Checks that a table or column comment matches a given description.
     *
     * @param string $description
     *   The asserted description.
     * @param string $table
     *   The table to test.
     * @param string|null $column
     *   Optional column to test.
     */
    public abstract function checkSchemaComment(string $description, string $table, ?string $column = NULL) : void;
    
    /**
     * Tests inserting data into an existing table.
     *
     * @param string $table
     *   The database table to insert data into.
     *
     * @return bool
     *   TRUE if the insert succeeded, FALSE otherwise.
     */
    public function tryInsert(string $table = 'test_table') : bool {
        try {
            $this->connection
                ->insert($table)
                ->fields([
                'id' => mt_rand(10, 20),
            ])
                ->execute();
            return TRUE;
        } catch (\Exception) {
            return FALSE;
        }
    }
    
    /**
     * Tries to insert a negative value into columns defined as unsigned.
     *
     * @param string $table_name
     *   The table to insert.
     * @param string $column_name
     *   The column to insert.
     *
     * @return bool
     *   TRUE if the insert succeeded, FALSE otherwise.
     */
    public function tryUnsignedInsert(string $table_name, string $column_name) : bool {
        try {
            $this->connection
                ->insert($table_name)
                ->fields([
                $column_name => -1,
            ])
                ->execute();
            return TRUE;
        } catch (\Exception) {
            return FALSE;
        }
    }
    
    /**
     * Tries to insert a value that throws an IntegrityConstraintViolationException.
     *
     * @param string $tableName
     *   The table to insert.
     */
    protected function tryInsertExpectsIntegrityConstraintViolationException(string $tableName) : void {
        try {
            $this->connection
                ->insert($tableName)
                ->fields([
                'test_field_string' => 'test',
            ])
                ->execute();
            $this->fail('Expected IntegrityConstraintViolationException not thrown');
        } catch (IntegrityConstraintViolationException) {
            // Do nothing, it's the expected behavior.
        }
    }
    
    /**
     * Asserts that fields have the correct collation, if supported.
     */
    protected function assertCollation() : void {
        // Driver specific tests should implement this when appropriate.
    }
    
    /**
     * Check that the ID sequence gets renamed when the table is renamed.
     *
     * @param string $tableName
     *   The table to rename.
     */
    protected function checkSequenceRenaming(string $tableName) : void {
        // Driver specific tests should implement this when appropriate.
    }
    
    /**
     * Tests database interactions.
     */
    public function testSchema() : void {
        // Try creating a table.
        $table_specification = [
            'description' => 'Schema table description may contain "quotes" and could be long—very long indeed.',
            'fields' => [
                'id' => [
                    'type' => 'int',
                    'default' => NULL,
                ],
                'test_field' => [
                    'type' => 'int',
                    'not null' => TRUE,
                    'description' => 'Schema table description may contain "quotes" and could be long—very long indeed. There could be "multiple quoted regions".',
                ],
                'test_field_string' => [
                    'type' => 'varchar',
                    'length' => 20,
                    'not null' => TRUE,
                    'default' => "'\"funky default'\"",
                    'description' => 'Schema column description for string.',
                ],
                'test_field_string_ascii' => [
                    'type' => 'varchar_ascii',
                    'length' => 255,
                    'description' => 'Schema column description for ASCII string.',
                ],
            ],
        ];
        $this->schema
            ->createTable('test_table', $table_specification);
        // Assert that the table exists.
        $this->assertTrue($this->schema
            ->tableExists('test_table'), 'The table exists.');
        // Assert that the table comment has been set.
        $this->checkSchemaComment($table_specification['description'], 'test_table');
        // Assert that the column comment has been set.
        $this->checkSchemaComment($table_specification['fields']['test_field']['description'], 'test_table', 'test_field');
        // Make sure that fields have the correct collation, if supported.
        $this->assertCollation();
        // An insert without a value for the column 'test_table' should fail.
        $this->assertFalse($this->tryInsert(), 'Insert without a default failed.');
        // Add a default value to the column.
        $this->schema
            ->changeField('test_table', 'test_field', 'test_field', [
            'type' => 'int',
            'not null' => TRUE,
            'default' => 0,
        ]);
        // The insert should now succeed.
        $this->assertTrue($this->tryInsert(), 'Insert with a default succeeded.');
        // Remove the default.
        $this->schema
            ->changeField('test_table', 'test_field', 'test_field', [
            'type' => 'int',
            'not null' => TRUE,
        ]);
        // The insert should fail again.
        $this->assertFalse($this->tryInsert(), 'Insert without a default failed.');
        // Test for fake index and test for the boolean result of indexExists().
        $index_exists = $this->schema
            ->indexExists('test_table', 'test_field');
        $this->assertFalse($index_exists, 'Fake index does not exist');
        // Add index.
        $this->schema
            ->addIndex('test_table', 'test_field', [
            'test_field',
        ], $table_specification);
        // Test for created index and test for the boolean result of indexExists().
        $index_exists = $this->schema
            ->indexExists('test_table', 'test_field');
        $this->assertTrue($index_exists, 'Index created.');
        // Rename the table.
        $this->assertNull($this->schema
            ->renameTable('test_table', 'test_table2'));
        // Index should be renamed.
        $index_exists = $this->schema
            ->indexExists('test_table2', 'test_field');
        $this->assertTrue($index_exists, 'Index was renamed.');
        // We need the default so that we can insert after the rename.
        $this->schema
            ->changeField('test_table2', 'test_field', 'test_field', [
            'type' => 'int',
            'not null' => TRUE,
            'default' => 0,
        ]);
        $this->assertFalse($this->tryInsert(), 'Insert into the old table failed.');
        $this->assertTrue($this->tryInsert('test_table2'), 'Insert into the new table succeeded.');
        // We should have successfully inserted exactly two rows.
        $count = $this->connection
            ->query('SELECT COUNT(*) FROM {test_table2}')
            ->fetchField();
        $this->assertEquals(2, $count, 'Two fields were successfully inserted.');
        // Try to drop the table.
        $this->schema
            ->dropTable('test_table2');
        $this->assertFalse($this->schema
            ->tableExists('test_table2'), 'The dropped table does not exist.');
        // Recreate the table.
        $this->schema
            ->createTable('test_table', $table_specification);
        $this->schema
            ->changeField('test_table', 'test_field', 'test_field', [
            'type' => 'int',
            'not null' => TRUE,
            'default' => 0,
        ]);
        $this->schema
            ->addField('test_table', 'test_serial', [
            'type' => 'int',
            'not null' => TRUE,
            'default' => 0,
            'description' => 'Added column description.',
        ]);
        // Assert that the column comment has been set.
        $this->checkSchemaComment('Added column description.', 'test_table', 'test_serial');
        // Change the new field to a serial column.
        $this->schema
            ->changeField('test_table', 'test_serial', 'test_serial', [
            'type' => 'serial',
            'not null' => TRUE,
            'description' => 'Changed column description.',
        ], [
            'primary key' => [
                'test_serial',
            ],
        ]);
        // Assert that the column comment has been set.
        $this->checkSchemaComment('Changed column description.', 'test_table', 'test_serial');
        $this->assertTrue($this->tryInsert(), 'Insert with a serial succeeded.');
        $max1 = $this->connection
            ->query('SELECT MAX([test_serial]) FROM {test_table}')
            ->fetchField();
        $this->assertTrue($this->tryInsert(), 'Insert with a serial succeeded.');
        $max2 = $this->connection
            ->query('SELECT MAX([test_serial]) FROM {test_table}')
            ->fetchField();
        $this->assertTrue($max2 > $max1, 'The serial is monotone.');
        $count = $this->connection
            ->query('SELECT COUNT(*) FROM {test_table}')
            ->fetchField();
        $this->assertEquals(2, $count, 'There were two rows.');
        // Test adding a serial field to an existing table.
        $this->schema
            ->dropTable('test_table');
        $this->schema
            ->createTable('test_table', $table_specification);
        $this->schema
            ->changeField('test_table', 'test_field', 'test_field', [
            'type' => 'int',
            'not null' => TRUE,
            'default' => 0,
        ]);
        $this->schema
            ->addField('test_table', 'test_serial', [
            'type' => 'serial',
            'not null' => TRUE,
        ], [
            'primary key' => [
                'test_serial',
            ],
        ]);
        // Test the primary key columns.
        $method = new \ReflectionMethod(get_class($this->schema), 'findPrimaryKeyColumns');
        $this->assertSame([
            'test_serial',
        ], $method->invoke($this->schema, 'test_table'));
        $this->assertTrue($this->tryInsert(), 'Insert with a serial succeeded.');
        $max1 = $this->connection
            ->query('SELECT MAX([test_serial]) FROM {test_table}')
            ->fetchField();
        $this->assertTrue($this->tryInsert(), 'Insert with a serial succeeded.');
        $max2 = $this->connection
            ->query('SELECT MAX([test_serial]) FROM {test_table}')
            ->fetchField();
        $this->assertTrue($max2 > $max1, 'The serial is monotone.');
        $count = $this->connection
            ->query('SELECT COUNT(*) FROM {test_table}')
            ->fetchField();
        $this->assertEquals(2, $count, 'There were two rows.');
        // Test adding a new column and form a composite primary key with it.
        $this->schema
            ->addField('test_table', 'test_composite_primary_key', [
            'type' => 'int',
            'not null' => TRUE,
            'default' => 0,
        ], [
            'primary key' => [
                'test_serial',
                'test_composite_primary_key',
            ],
        ]);
        // Test the primary key columns.
        $this->assertSame([
            'test_serial',
            'test_composite_primary_key',
        ], $method->invoke($this->schema, 'test_table'));
        // Test renaming of keys and constraints.
        $this->schema
            ->dropTable('test_table');
        $table_specification = [
            'fields' => [
                'id' => [
                    'type' => 'serial',
                    'not null' => TRUE,
                ],
                'test_field' => [
                    'type' => 'int',
                    'default' => 0,
                ],
            ],
            'primary key' => [
                'id',
            ],
            'unique keys' => [
                'test_field' => [
                    'test_field',
                ],
            ],
        ];
        // PostgreSQL has a max identifier length of 63 characters, MySQL has 64 and
        // SQLite does not have any limit. Use the lowest common value and create a
        // table name as long as possible in order to cover edge cases around
        // identifier names for the table's primary or unique key constraints.
        $table_name = strtolower($this->getRandomGenerator()
            ->name(63 - strlen($this->getDatabasePrefix())));
        $this->schema
            ->createTable($table_name, $table_specification);
        $this->assertIndexOnColumns($table_name, [
            'id',
        ], 'primary');
        $this->assertIndexOnColumns($table_name, [
            'test_field',
        ], 'unique');
        $new_table_name = strtolower($this->getRandomGenerator()
            ->name(63 - strlen($this->getDatabasePrefix())));
        $this->assertNull($this->schema
            ->renameTable($table_name, $new_table_name));
        // Test for renamed primary and unique keys.
        $this->assertIndexOnColumns($new_table_name, [
            'id',
        ], 'primary');
        $this->assertIndexOnColumns($new_table_name, [
            'test_field',
        ], 'unique');
        // Check that the ID sequence gets renamed when the table is renamed.
        $this->checkSequenceRenaming($new_table_name);
    }
    
    /**
     * Tests creating a table with database specific data type.
     */
    public abstract function testTableWithSpecificDataType() : void;
    
    /**
     * Tests creating unsigned columns and data integrity thereof.
     */
    public function testUnsignedColumns() : void {
        // First create the table with just a serial column.
        $table_name = 'unsigned_table';
        $table_spec = [
            'fields' => [
                'serial_column' => [
                    'type' => 'serial',
                    'unsigned' => TRUE,
                    'not null' => TRUE,
                ],
            ],
            'primary key' => [
                'serial_column',
            ],
        ];
        $this->schema
            ->createTable($table_name, $table_spec);
        // Now set up columns for the other types.
        $types = [
            'int',
            'float',
            'numeric',
        ];
        foreach ($types as $type) {
            $column_spec = [
                'type' => $type,
                'unsigned' => TRUE,
            ];
            if ($type == 'numeric') {
                $column_spec += [
                    'precision' => 10,
                    'scale' => 0,
                ];
            }
            $column_name = $type . '_column';
            $table_spec['fields'][$column_name] = $column_spec;
            $this->schema
                ->addField($table_name, $column_name, $column_spec);
        }
        // Finally, check each column and try to insert invalid values into them.
        foreach ($table_spec['fields'] as $column_name => $column_spec) {
            $this->assertTrue($this->schema
                ->fieldExists($table_name, $column_name), "Unsigned {$column_spec['type']} column was created.");
            $this->assertFalse($this->tryUnsignedInsert($table_name, $column_name), "Unsigned {$column_spec['type']} column rejected a negative value.");
        }
    }
    
    /**
     * Tests adding columns to an existing table with default and initial value.
     */
    public function testSchemaAddFieldDefaultInitial() : void {
        // Test varchar types.
        foreach ([
            1,
            32,
            128,
            256,
            512,
        ] as $length) {
            $base_field_spec = [
                'type' => 'varchar',
                'length' => $length,
            ];
            $variations = [
                [
                    'not null' => FALSE,
                ],
                [
                    'not null' => FALSE,
                    'default' => '7',
                ],
                [
                    'not null' => FALSE,
                    'default' => substr('"thing"', 0, $length),
                ],
                [
                    'not null' => FALSE,
                    'default' => substr("\"'hing", 0, $length),
                ],
                [
                    'not null' => TRUE,
                    'initial' => 'd',
                ],
                [
                    'not null' => FALSE,
                    'default' => NULL,
                ],
                [
                    'not null' => TRUE,
                    'initial' => 'd',
                    'default' => '7',
                ],
            ];
            foreach ($variations as $variation) {
                $field_spec = $variation + $base_field_spec;
                $this->assertFieldAdditionRemoval($field_spec);
            }
        }
        // Test int and float types.
        foreach ([
            'int',
            'float',
        ] as $type) {
            foreach ([
                'tiny',
                'small',
                'medium',
                'normal',
                'big',
            ] as $size) {
                $base_field_spec = [
                    'type' => $type,
                    'size' => $size,
                ];
                $variations = [
                    [
                        'not null' => FALSE,
                    ],
                    [
                        'not null' => FALSE,
                        'default' => 7,
                    ],
                    [
                        'not null' => TRUE,
                        'initial' => 1,
                    ],
                    [
                        'not null' => TRUE,
                        'initial' => 1,
                        'default' => 7,
                    ],
                    [
                        'not null' => TRUE,
                        'initial_from_field' => 'serial_column',
                    ],
                    [
                        'not null' => TRUE,
                        'initial_from_field' => 'test_nullable_field',
                        'initial' => 100,
                    ],
                ];
                foreach ($variations as $variation) {
                    $field_spec = $variation + $base_field_spec;
                    $this->assertFieldAdditionRemoval($field_spec);
                }
            }
        }
        // Test numeric types.
        foreach ([
            1,
            5,
            10,
            40,
            65,
        ] as $precision) {
            foreach ([
                0,
                2,
                10,
                30,
            ] as $scale) {
                // Skip combinations where precision is smaller than scale.
                if ($precision <= $scale) {
                    continue;
                }
                $base_field_spec = [
                    'type' => 'numeric',
                    'scale' => $scale,
                    'precision' => $precision,
                ];
                $variations = [
                    [
                        'not null' => FALSE,
                    ],
                    [
                        'not null' => FALSE,
                        'default' => 7,
                    ],
                    [
                        'not null' => TRUE,
                        'initial' => 1,
                    ],
                    [
                        'not null' => TRUE,
                        'initial' => 1,
                        'default' => 7,
                    ],
                    [
                        'not null' => TRUE,
                        'initial_from_field' => 'serial_column',
                    ],
                ];
                foreach ($variations as $variation) {
                    $field_spec = $variation + $base_field_spec;
                    $this->assertFieldAdditionRemoval($field_spec);
                }
            }
        }
    }
    
    /**
     * Asserts that a given field can be added and removed from a table.
     *
     * The addition test covers both defining a field of a given specification
     * when initially creating at table and extending an existing table.
     *
     * @param array $field_spec
     *   The schema specification of the field.
     *
     * @internal
     */
    protected function assertFieldAdditionRemoval(array $field_spec) : void {
        // Try creating the field on a new table.
        $table_name = 'test_table_' . $this->counter++;
        $table_spec = [
            'fields' => [
                'serial_column' => [
                    'type' => 'serial',
                    'unsigned' => TRUE,
                    'not null' => TRUE,
                ],
                'test_nullable_field' => [
                    'type' => 'int',
                    'not null' => FALSE,
                ],
                'test_field' => $field_spec,
            ],
            'primary key' => [
                'serial_column',
            ],
        ];
        $this->schema
            ->createTable($table_name, $table_spec);
        // Check the characteristics of the field.
        $this->assertFieldCharacteristics($table_name, 'test_field', $field_spec);
        // Clean-up.
        $this->schema
            ->dropTable($table_name);
        // Try adding a field to an existing table.
        $table_name = 'test_table_' . $this->counter++;
        $table_spec = [
            'fields' => [
                'serial_column' => [
                    'type' => 'serial',
                    'unsigned' => TRUE,
                    'not null' => TRUE,
                ],
                'test_nullable_field' => [
                    'type' => 'int',
                    'not null' => FALSE,
                ],
            ],
            'primary key' => [
                'serial_column',
            ],
        ];
        $this->schema
            ->createTable($table_name, $table_spec);
        // Insert some rows to the table to test the handling of initial values.
        for ($i = 0; $i < 3; $i++) {
            $this->connection
                ->insert($table_name)
                ->useDefaults([
                'serial_column',
            ])
                ->fields([
                'test_nullable_field' => 100,
            ])
                ->execute();
        }
        // Add another row with no value for the 'test_nullable_field' column.
        $this->connection
            ->insert($table_name)
            ->useDefaults([
            'serial_column',
        ])
            ->execute();
        $this->schema
            ->addField($table_name, 'test_field', $field_spec);
        // Check the characteristics of the field.
        $this->assertFieldCharacteristics($table_name, 'test_field', $field_spec);
        // Clean-up.
        $this->schema
            ->dropField($table_name, 'test_field');
        // Add back the field and then try to delete a field which is also a primary
        // key.
        $this->schema
            ->addField($table_name, 'test_field', $field_spec);
        $this->schema
            ->dropField($table_name, 'serial_column');
        $this->schema
            ->dropTable($table_name);
    }
    
    /**
     * Asserts that a newly added field has the correct characteristics.
     *
     * @internal
     */
    protected function assertFieldCharacteristics(string $table_name, string $field_name, array $field_spec) : void {
        // Check that the initial value has been registered.
        if (isset($field_spec['initial'])) {
            // There should be no row with a value different then $field_spec['initial'].
            $count = $this->connection
                ->select($table_name)
                ->fields($table_name, [
                'serial_column',
            ])
                ->condition($field_name, $field_spec['initial'], '<>')
                ->countQuery()
                ->execute()
                ->fetchField();
            $this->assertEquals(0, $count, 'Initial values filled out.');
        }
        // Check that the initial value from another field has been registered.
        if (isset($field_spec['initial_from_field']) && !isset($field_spec['initial'])) {
            // There should be no row with a value different than
            // $field_spec['initial_from_field'].
            $count = $this->connection
                ->select($table_name)
                ->fields($table_name, [
                'serial_column',
            ])
                ->where("[{$table_name}].[{$field_spec['initial_from_field']}] <> [{$table_name}].[{$field_name}]")
                ->countQuery()
                ->execute()
                ->fetchField();
            $this->assertEquals(0, $count, 'Initial values from another field filled out.');
        }
        elseif (isset($field_spec['initial_from_field']) && isset($field_spec['initial'])) {
            // There should be no row with a value different than '100'.
            $count = $this->connection
                ->select($table_name)
                ->fields($table_name, [
                'serial_column',
            ])
                ->condition($field_name, 100, '<>')
                ->countQuery()
                ->execute()
                ->fetchField();
            $this->assertEquals(0, $count, 'Initial values from another field or a default value filled out.');
        }
        // Check that the default value has been registered.
        if (isset($field_spec['default'])) {
            // Try inserting a row, and check the resulting value of the new column.
            $id = $this->connection
                ->insert($table_name)
                ->useDefaults([
                'serial_column',
            ])
                ->execute();
            $field_value = $this->connection
                ->select($table_name)
                ->fields($table_name, [
                $field_name,
            ])
                ->condition('serial_column', $id)
                ->execute()
                ->fetchField();
            $this->assertEquals($field_spec['default'], $field_value, 'Default value registered.');
        }
    }
    
    /**
     * Tests various schema changes' effect on the table's primary key.
     *
     * @param array $initial_primary_key
     *   The initial primary key of the test table.
     * @param array $renamed_primary_key
     *   The primary key of the test table after renaming the test field.
     *
     * @dataProvider providerTestSchemaCreateTablePrimaryKey
     *
     * @covers ::addField
     * @covers ::changeField
     * @covers ::dropField
     * @covers ::findPrimaryKeyColumns
     */
    public function testSchemaChangePrimaryKey(array $initial_primary_key, array $renamed_primary_key) : void {
        $find_primary_key_columns = new \ReflectionMethod(get_class($this->schema), 'findPrimaryKeyColumns');
        // Test making the field the primary key of the table upon creation.
        $table_name = 'test_table';
        $table_spec = [
            'fields' => [
                'test_field' => [
                    'type' => 'int',
                    'not null' => TRUE,
                ],
                'other_test_field' => [
                    'type' => 'int',
                    'not null' => TRUE,
                ],
            ],
            'primary key' => $initial_primary_key,
        ];
        $this->schema
            ->createTable($table_name, $table_spec);
        $this->assertTrue($this->schema
            ->fieldExists($table_name, 'test_field'));
        $this->assertEquals($initial_primary_key, $find_primary_key_columns->invoke($this->schema, $table_name));
        // Change the field type and make sure the primary key stays in place.
        $this->schema
            ->changeField($table_name, 'test_field', 'test_field', [
            'type' => 'varchar',
            'length' => 32,
            'not null' => TRUE,
        ]);
        $this->assertTrue($this->schema
            ->fieldExists($table_name, 'test_field'));
        $this->assertEquals($initial_primary_key, $find_primary_key_columns->invoke($this->schema, $table_name));
        // Add some data and change the field type back, to make sure that changing
        // the type leaves the primary key in place even with existing data.
        $this->connection
            ->insert($table_name)
            ->fields([
            'test_field' => 1,
            'other_test_field' => 2,
        ])
            ->execute();
        $this->schema
            ->changeField($table_name, 'test_field', 'test_field', [
            'type' => 'int',
            'not null' => TRUE,
        ]);
        $this->assertTrue($this->schema
            ->fieldExists($table_name, 'test_field'));
        $this->assertEquals($initial_primary_key, $find_primary_key_columns->invoke($this->schema, $table_name));
        // Make sure that adding the primary key can be done as part of changing
        // a field, as well.
        $this->schema
            ->dropPrimaryKey($table_name);
        $this->assertEquals([], $find_primary_key_columns->invoke($this->schema, $table_name));
        $this->schema
            ->changeField($table_name, 'test_field', 'test_field', [
            'type' => 'int',
            'not null' => TRUE,
        ], [
            'primary key' => $initial_primary_key,
        ]);
        $this->assertTrue($this->schema
            ->fieldExists($table_name, 'test_field'));
        $this->assertEquals($initial_primary_key, $find_primary_key_columns->invoke($this->schema, $table_name));
        // Rename the field and make sure the primary key was updated.
        $this->schema
            ->changeField($table_name, 'test_field', 'test_field_renamed', [
            'type' => 'int',
            'not null' => TRUE,
        ]);
        $this->assertTrue($this->schema
            ->fieldExists($table_name, 'test_field_renamed'));
        $this->assertEquals($renamed_primary_key, $find_primary_key_columns->invoke($this->schema, $table_name));
        // Drop the field and make sure the primary key was dropped, as well.
        $this->schema
            ->dropField($table_name, 'test_field_renamed');
        $this->assertFalse($this->schema
            ->fieldExists($table_name, 'test_field_renamed'));
        $this->assertEquals([], $find_primary_key_columns->invoke($this->schema, $table_name));
        // Add the field again and make sure adding the primary key can be done at
        // the same time.
        $this->schema
            ->addField($table_name, 'test_field', [
            'type' => 'int',
            'default' => 0,
            'not null' => TRUE,
        ], [
            'primary key' => $initial_primary_key,
        ]);
        $this->assertTrue($this->schema
            ->fieldExists($table_name, 'test_field'));
        $this->assertEquals($initial_primary_key, $find_primary_key_columns->invoke($this->schema, $table_name));
        // Drop the field again and explicitly add a primary key.
        $this->schema
            ->dropField($table_name, 'test_field');
        $this->schema
            ->addPrimaryKey($table_name, [
            'other_test_field',
        ]);
        $this->assertFalse($this->schema
            ->fieldExists($table_name, 'test_field'));
        $this->assertEquals([
            'other_test_field',
        ], $find_primary_key_columns->invoke($this->schema, $table_name));
        // Test that adding a field with a primary key will work even with a
        // pre-existing primary key.
        $this->schema
            ->addField($table_name, 'test_field', [
            'type' => 'int',
            'default' => 0,
            'not null' => TRUE,
        ], [
            'primary key' => $initial_primary_key,
        ]);
        $this->assertTrue($this->schema
            ->fieldExists($table_name, 'test_field'));
        $this->assertEquals($initial_primary_key, $find_primary_key_columns->invoke($this->schema, $table_name));
    }
    
    /**
     * Provides test cases for SchemaTest::testSchemaCreateTablePrimaryKey().
     *
     * @return array
     *   An array of test cases for SchemaTest::testSchemaCreateTablePrimaryKey().
     */
    public static function providerTestSchemaCreateTablePrimaryKey() {
        $tests = [];
        $tests['simple_primary_key'] = [
            'initial_primary_key' => [
                'test_field',
            ],
            'renamed_primary_key' => [
                'test_field_renamed',
            ],
        ];
        $tests['composite_primary_key'] = [
            'initial_primary_key' => [
                'test_field',
                'other_test_field',
            ],
            'renamed_primary_key' => [
                'test_field_renamed',
                'other_test_field',
            ],
        ];
        $tests['composite_primary_key_different_order'] = [
            'initial_primary_key' => [
                'other_test_field',
                'test_field',
            ],
            'renamed_primary_key' => [
                'other_test_field',
                'test_field_renamed',
            ],
        ];
        return $tests;
    }
    
    /**
     * Tests an invalid field specification as a primary key on table creation.
     */
    public function testInvalidPrimaryKeyOnTableCreation() : void {
        // Test making an invalid field the primary key of the table upon creation.
        $table_name = 'test_table';
        $table_spec = [
            'fields' => [
                'test_field' => [
                    'type' => 'int',
                ],
            ],
            'primary key' => [
                'test_field',
            ],
        ];
        $this->expectException(SchemaException::class);
        $this->expectExceptionMessage("The 'test_field' field specification does not define 'not null' as TRUE.");
        $this->schema
            ->createTable($table_name, $table_spec);
    }
    
    /**
     * Tests converting an int to a serial when the int column has data.
     */
    public function testChangePrimaryKeyToSerial() : void {
        // Test making an invalid field the primary key of the table upon creation.
        $table_name = 'test_table';
        $table_spec = [
            'fields' => [
                'test_field' => [
                    'type' => 'int',
                    'not null' => TRUE,
                ],
                'test_field_string' => [
                    'type' => 'varchar',
                    'length' => 20,
                ],
            ],
            'primary key' => [
                'test_field',
            ],
        ];
        $this->schema
            ->createTable($table_name, $table_spec);
        $this->tryInsertExpectsIntegrityConstraintViolationException($table_name);
        // @todo https://www.drupal.org/project/drupal/issues/3222127 Change the
        //   first item to 0 to test changing a field with 0 to a serial.
        // Create 8 rows in the table. Note that the 5 value is deliberately
        // omitted.
        foreach ([
            1,
            2,
            3,
            4,
            6,
            7,
            8,
            9,
        ] as $value) {
            $this->connection
                ->insert($table_name)
                ->fields([
                'test_field' => $value,
            ])
                ->execute();
        }
        $this->schema
            ->changeField($table_name, 'test_field', 'test_field', [
            'type' => 'serial',
            'not null' => TRUE,
        ]);
        $data = $this->connection
            ->select($table_name)
            ->fields($table_name, [
            'test_field',
        ])
            ->execute()
            ->fetchCol();
        $this->assertEquals([
            1,
            2,
            3,
            4,
            6,
            7,
            8,
            9,
        ], array_values($data));
        try {
            $this->connection
                ->insert($table_name)
                ->fields([
                'test_field' => 1,
            ])
                ->execute();
            $this->fail('Expected IntegrityConstraintViolationException not thrown');
        } catch (IntegrityConstraintViolationException) {
        }
        // Ensure auto numbering now works.
        // We use a >= assertion to allow non-core drivers, that may have specific
        // strategies on automatic incrementing, to run core tests. For example,
        // Oracle will allocate a 10 id with the previous insert that was meant to
        // fail; that id will be discarded, and the insert here will get a new 11
        // id instead.
        $id = $this->connection
            ->insert($table_name)
            ->fields([
            'test_field_string' => 'test',
        ])
            ->execute();
        $this->assertGreaterThanOrEqual(10, $id);
    }
    
    /**
     * Tests adding an invalid field specification as a primary key.
     */
    public function testInvalidPrimaryKeyAddition() : void {
        // Test adding a new invalid field to the primary key.
        $table_name = 'test_table';
        $table_spec = [
            'fields' => [
                'test_field' => [
                    'type' => 'int',
                    'not null' => TRUE,
                ],
            ],
            'primary key' => [
                'test_field',
            ],
        ];
        $this->schema
            ->createTable($table_name, $table_spec);
        $this->expectException(SchemaException::class);
        $this->expectExceptionMessage("The 'new_test_field' field specification does not define 'not null' as TRUE.");
        $this->schema
            ->addField($table_name, 'new_test_field', [
            'type' => 'int',
        ], [
            'primary key' => [
                'test_field',
                'new_test_field',
            ],
        ]);
    }
    
    /**
     * Tests changing the primary key with an invalid field specification.
     */
    public function testInvalidPrimaryKeyChange() : void {
        // Test adding a new invalid field to the primary key.
        $table_name = 'test_table';
        $table_spec = [
            'fields' => [
                'test_field' => [
                    'type' => 'int',
                    'not null' => TRUE,
                ],
            ],
            'primary key' => [
                'test_field',
            ],
        ];
        $this->schema
            ->createTable($table_name, $table_spec);
        $this->expectException(SchemaException::class);
        $this->expectExceptionMessage("The 'changed_test_field' field specification does not define 'not null' as TRUE.");
        $this->schema
            ->dropPrimaryKey($table_name);
        $this->schema
            ->changeField($table_name, 'test_field', 'changed_test_field', [
            'type' => 'int',
        ], [
            'primary key' => [
                'changed_test_field',
            ],
        ]);
    }
    
    /**
     * Tests changing columns between types with default and initial values.
     */
    public function testSchemaChangeFieldDefaultInitial() : void {
        $field_specs = [
            [
                'type' => 'int',
                'size' => 'normal',
                'not null' => FALSE,
            ],
            [
                'type' => 'int',
                'size' => 'normal',
                'not null' => TRUE,
                'initial' => 1,
                'default' => 17,
            ],
            [
                'type' => 'float',
                'size' => 'normal',
                'not null' => FALSE,
            ],
            [
                'type' => 'float',
                'size' => 'normal',
                'not null' => TRUE,
                'initial' => 1,
                'default' => 7.3,
            ],
            [
                'type' => 'numeric',
                'scale' => 2,
                'precision' => 10,
                'not null' => FALSE,
            ],
            [
                'type' => 'numeric',
                'scale' => 2,
                'precision' => 10,
                'not null' => TRUE,
                'initial' => 1,
                'default' => 7,
            ],
        ];
        foreach ($field_specs as $i => $old_spec) {
            foreach ($field_specs as $j => $new_spec) {
                if ($i === $j) {
                    // Do not change a field into itself.
                    continue;
                }
                $this->assertFieldChange($old_spec, $new_spec);
            }
        }
        $field_specs = [
            [
                'type' => 'varchar_ascii',
                'length' => '255',
            ],
            [
                'type' => 'varchar',
                'length' => '255',
            ],
            [
                'type' => 'text',
            ],
            [
                'type' => 'blob',
                'size' => 'big',
            ],
        ];
        foreach ($field_specs as $i => $old_spec) {
            foreach ($field_specs as $j => $new_spec) {
                if ($i === $j) {
                    // Do not change a field into itself.
                    continue;
                }
                // Note if the serialized data contained an object this would fail on
                // Postgres.
                // @see https://www.drupal.org/node/1031122
                $this->assertFieldChange($old_spec, $new_spec, serialize([
                    'string' => "This \n has \\\\ some backslash \"*string action.\\n",
                ]));
            }
        }
    }
    
    /**
     * Asserts that a field can be changed from one spec to another.
     *
     * @param array $old_spec
     *   The beginning field specification.
     * @param array $new_spec
     *   The ending field specification.
     * @param mixed $test_data
     *   (optional) A test value to insert and test, if specified.
     *
     * @internal
     */
    protected function assertFieldChange(array $old_spec, array $new_spec, $test_data = NULL) : void {
        $table_name = 'test_table_' . $this->counter++;
        $table_spec = [
            'fields' => [
                'serial_column' => [
                    'type' => 'serial',
                    'unsigned' => TRUE,
                    'not null' => TRUE,
                ],
                'test_field' => $old_spec,
            ],
            'primary key' => [
                'serial_column',
            ],
        ];
        $this->schema
            ->createTable($table_name, $table_spec);
        // Check the characteristics of the field.
        $this->assertFieldCharacteristics($table_name, 'test_field', $old_spec);
        // Remove inserted rows.
        $this->connection
            ->truncate($table_name)
            ->execute();
        if ($test_data) {
            $id = $this->connection
                ->insert($table_name)
                ->fields([
                'test_field',
            ], [
                $test_data,
            ])
                ->execute();
        }
        // Change the field.
        $this->schema
            ->changeField($table_name, 'test_field', 'test_field', $new_spec);
        if ($test_data) {
            $field_value = $this->connection
                ->select($table_name)
                ->fields($table_name, [
                'test_field',
            ])
                ->condition('serial_column', $id)
                ->execute()
                ->fetchField();
            $this->assertSame($test_data, $field_value);
        }
        // Check the field was changed.
        $this->assertFieldCharacteristics($table_name, 'test_field', $new_spec);
        // Clean-up.
        $this->schema
            ->dropTable($table_name);
    }
    
    /**
     * @covers ::findPrimaryKeyColumns
     */
    public function testFindPrimaryKeyColumns() : void {
        $method = new \ReflectionMethod(get_class($this->schema), 'findPrimaryKeyColumns');
        // Test with single column primary key.
        $this->schema
            ->createTable('table_with_pk_0', [
            'description' => 'Table with primary key.',
            'fields' => [
                'id' => [
                    'type' => 'int',
                    'not null' => TRUE,
                ],
                'test_field' => [
                    'type' => 'int',
                    'not null' => TRUE,
                ],
            ],
            'primary key' => [
                'id',
            ],
        ]);
        $this->assertSame([
            'id',
        ], $method->invoke($this->schema, 'table_with_pk_0'));
        // Test with multiple column primary key.
        $this->schema
            ->createTable('table_with_pk_1', [
            'description' => 'Table with primary key with multiple columns.',
            'fields' => [
                'id0' => [
                    'type' => 'int',
                    'not null' => TRUE,
                ],
                'id1' => [
                    'type' => 'int',
                    'not null' => TRUE,
                ],
                'test_field' => [
                    'type' => 'int',
                    'not null' => TRUE,
                ],
            ],
            'primary key' => [
                'id0',
                'id1',
            ],
        ]);
        $this->assertSame([
            'id0',
            'id1',
        ], $method->invoke($this->schema, 'table_with_pk_1'));
        // Test with multiple column primary key and not being the first column of
        // the table definition.
        $this->schema
            ->createTable('table_with_pk_2', [
            'description' => 'Table with primary key with multiple columns at the end and in reverted sequence.',
            'fields' => [
                'test_field_1' => [
                    'type' => 'int',
                    'not null' => TRUE,
                ],
                'test_field_2' => [
                    'type' => 'int',
                    'not null' => TRUE,
                ],
                'id3' => [
                    'type' => 'int',
                    'not null' => TRUE,
                ],
                'id4' => [
                    'type' => 'int',
                    'not null' => TRUE,
                ],
            ],
            'primary key' => [
                'id4',
                'id3',
            ],
        ]);
        $this->assertSame([
            'id4',
            'id3',
        ], $method->invoke($this->schema, 'table_with_pk_2'));
        // Test with multiple column primary key in a different order. For the
        // PostgreSQL and the SQLite drivers is sorting used to get the primary key
        // columns in the right order.
        $this->schema
            ->createTable('table_with_pk_3', [
            'description' => 'Table with primary key with multiple columns at the end and in reverted sequence.',
            'fields' => [
                'test_field_1' => [
                    'type' => 'int',
                    'not null' => TRUE,
                ],
                'test_field_2' => [
                    'type' => 'int',
                    'not null' => TRUE,
                ],
                'id3' => [
                    'type' => 'int',
                    'not null' => TRUE,
                ],
                'id4' => [
                    'type' => 'int',
                    'not null' => TRUE,
                ],
            ],
            'primary key' => [
                'id3',
                'test_field_2',
                'id4',
            ],
        ]);
        $this->assertSame([
            'id3',
            'test_field_2',
            'id4',
        ], $method->invoke($this->schema, 'table_with_pk_3'));
        // Test with table without a primary key.
        $this->schema
            ->createTable('table_without_pk_1', [
            'description' => 'Table without primary key.',
            'fields' => [
                'id' => [
                    'type' => 'int',
                    'not null' => TRUE,
                ],
                'test_field' => [
                    'type' => 'int',
                    'not null' => TRUE,
                ],
            ],
        ]);
        $this->assertSame([], $method->invoke($this->schema, 'table_without_pk_1'));
        // Test with table with an empty primary key.
        $this->schema
            ->createTable('table_without_pk_2', [
            'description' => 'Table without primary key.',
            'fields' => [
                'id' => [
                    'type' => 'int',
                    'not null' => TRUE,
                ],
                'test_field' => [
                    'type' => 'int',
                    'not null' => TRUE,
                ],
            ],
            'primary key' => [],
        ]);
        $this->assertSame([], $method->invoke($this->schema, 'table_without_pk_2'));
        // Test with non existing table.
        $this->assertFalse($method->invoke($this->schema, 'non_existing_table'));
    }
    
    /**
     * Tests the findTables() method.
     */
    public function testFindTables() : void {
        // We will be testing with three tables.
        $test_schema = Database::getConnection()->schema();
        // Create the tables.
        $table_specification = [
            'description' => 'Test table.',
            'fields' => [
                'id' => [
                    'type' => 'int',
                    'default' => NULL,
                ],
            ],
        ];
        $test_schema->createTable('test_1_table', $table_specification);
        $test_schema->createTable('test_2_table', $table_specification);
        $test_schema->createTable('the_third_table', $table_specification);
        // Check the "all tables" syntax.
        $tables = $test_schema->findTables('%');
        sort($tables);
        $expected = [
            // The 'config' table is added by
            // \Drupal\KernelTests\KernelTestBase::containerBuild().
'config',
            'test_1_table',
            // This table uses a per-table prefix, yet it is returned as un-prefixed.
'test_2_table',
            'the_third_table',
        ];
        $this->assertEquals($expected, $tables, 'All tables were found.');
        // Check the restrictive syntax.
        $tables = $test_schema->findTables('test_%');
        sort($tables);
        $expected = [
            'test_1_table',
            'test_2_table',
        ];
        $this->assertEquals($expected, $tables, 'Two tables were found.');
        // Check '_' and '%' wildcards.
        $test_schema->createTable('test3table', $table_specification);
        $test_schema->createTable('test4', $table_specification);
        $test_schema->createTable('testTable', $table_specification);
        $test_schema->createTable('test', $table_specification);
        $tables = $test_schema->findTables('test%');
        sort($tables);
        $expected = [
            'test',
            'test3table',
            'test4',
            'testTable',
            'test_1_table',
            'test_2_table',
        ];
        $this->assertEquals($expected, $tables, 'All "test" prefixed tables were found.');
        $tables = $test_schema->findTables('test_%');
        sort($tables);
        $expected = [
            'test3table',
            'test4',
            'testTable',
            'test_1_table',
            'test_2_table',
        ];
        $this->assertEquals($expected, $tables, 'All "/^test..*?/" tables were found.');
        $tables = $test_schema->findTables('test%table');
        sort($tables);
        $expected = [
            'test3table',
            'testTable',
            'test_1_table',
            'test_2_table',
        ];
        $this->assertEquals($expected, $tables, 'All "/^test.*?table/" tables were found.');
        $tables = $test_schema->findTables('test_%table');
        sort($tables);
        $expected = [
            'test3table',
            'test_1_table',
            'test_2_table',
        ];
        $this->assertEquals($expected, $tables, 'All "/^test..*?table/" tables were found.');
        $tables = $test_schema->findTables('test_');
        sort($tables);
        $expected = [
            'test4',
        ];
        $this->assertEquals($expected, $tables, 'All "/^test./" tables were found.');
    }
    
    /**
     * Tests handling of uppercase table names.
     */
    public function testUpperCaseTableName() : void {
        $table_name = 'A_UPPER_CASE_TABLE_NAME';
        // Create the tables.
        $table_specification = [
            'description' => 'Test table.',
            'fields' => [
                'id' => [
                    'type' => 'int',
                    'default' => NULL,
                ],
            ],
        ];
        $this->schema
            ->createTable($table_name, $table_specification);
        $this->assertTrue($this->schema
            ->tableExists($table_name), 'Table with uppercase table name exists');
        $this->assertContains($table_name, $this->schema
            ->findTables('%'));
        $this->assertTrue($this->schema
            ->dropTable($table_name), 'Table with uppercase table name dropped');
    }
    
    /**
     * Tests default values after altering table.
     */
    public function testDefaultAfterAlter() : void {
        $table_name = 'test_table';
        // Create the table.
        $table_specification = [
            'description' => 'Test table.',
            'fields' => [
                'column1' => [
                    'type' => 'int',
                    'default' => NULL,
                ],
                'column2' => [
                    'type' => 'varchar',
                    'length' => 20,
                    'default' => NULL,
                ],
                'column3' => [
                    'type' => 'int',
                    'default' => 200,
                ],
                'column4' => [
                    'type' => 'float',
                    'default' => 1.23,
                ],
                'column5' => [
                    'type' => 'varchar',
                    'length' => 20,
                    'default' => "'s o'clock'",
                ],
                'column6' => [
                    'type' => 'varchar',
                    'length' => 20,
                    'default' => "o'clock",
                ],
                'column7' => [
                    'type' => 'varchar',
                    'length' => 20,
                    'default' => 'default value',
                ],
            ],
        ];
        $this->schema
            ->createTable($table_name, $table_specification);
        // Insert a row and check that columns have the expected default values.
        $this->connection
            ->insert($table_name)
            ->fields([
            'column1' => 1,
        ])
            ->execute();
        $result = $this->connection
            ->select($table_name, 't')
            ->fields('t', [
            'column2',
            'column3',
            'column4',
            'column5',
            'column6',
            'column7',
        ])
            ->condition('column1', 1)
            ->execute()
            ->fetchObject();
        $this->assertNull($result->column2);
        $this->assertSame('200', $result->column3);
        $this->assertSame('1.23', $result->column4);
        $this->assertSame("'s o'clock'", $result->column5);
        $this->assertSame("o'clock", $result->column6);
        $this->assertSame('default value', $result->column7);
        // Force SQLite schema to create a new table and copy data by adding a not
        // field with an initial value.
        $this->schema
            ->addField('test_table', 'new_column', [
            'type' => 'varchar',
            'length' => 20,
            'not null' => TRUE,
            'description' => 'Added new column',
            'initial' => 'test',
        ]);
        // Test that the columns default values are still correct.
        $this->connection
            ->insert($table_name)
            ->fields([
            'column1' => 2,
            'new_column' => 'value',
        ])
            ->execute();
        $result = $this->connection
            ->select($table_name, 't')
            ->fields('t', [
            'column2',
            'column3',
            'column4',
            'column5',
            'column6',
            'column7',
        ])
            ->condition('column1', 2)
            ->execute()
            ->fetchObject();
        $this->assertNull($result->column2);
        $this->assertSame('200', $result->column3);
        $this->assertSame('1.23', $result->column4);
        $this->assertSame("'s o'clock'", $result->column5);
        $this->assertSame("o'clock", $result->column6);
        $this->assertSame('default value', $result->column7);
    }
    
    /**
     * Tests handling with reserved keywords for naming tables, fields and more.
     */
    public function testReservedKeywordsForNaming() : void {
        $table_specification = [
            'description' => 'A test table with an ANSI reserved keywords for naming.',
            'fields' => [
                'primary' => [
                    'description' => 'Simple unique ID.',
                    'type' => 'int',
                    'not null' => TRUE,
                ],
                'update' => [
                    'description' => 'A column with reserved name.',
                    'type' => 'varchar',
                    'length' => 255,
                ],
            ],
            'primary key' => [
                'primary',
            ],
            'unique keys' => [
                'having' => [
                    'update',
                ],
            ],
            'indexes' => [
                'in' => [
                    'primary',
                    'update',
                ],
            ],
        ];
        // Creating a table.
        $table_name = 'select';
        $this->schema
            ->createTable($table_name, $table_specification);
        $this->assertTrue($this->schema
            ->tableExists($table_name));
        // Finding all tables.
        $tables = $this->schema
            ->findTables('%');
        sort($tables);
        $this->assertEquals([
            'config',
            'select',
        ], $tables);
        // Renaming a table.
        $table_name_new = 'from';
        $this->schema
            ->renameTable($table_name, $table_name_new);
        $this->assertFalse($this->schema
            ->tableExists($table_name));
        $this->assertTrue($this->schema
            ->tableExists($table_name_new));
        // Adding a field.
        $field_name = 'delete';
        $this->schema
            ->addField($table_name_new, $field_name, [
            'type' => 'int',
            'not null' => TRUE,
        ]);
        $this->assertTrue($this->schema
            ->fieldExists($table_name_new, $field_name));
        // Dropping a primary key.
        $this->schema
            ->dropPrimaryKey($table_name_new);
        // Adding a primary key.
        $this->schema
            ->addPrimaryKey($table_name_new, [
            $field_name,
        ]);
        // Check the primary key columns.
        $find_primary_key_columns = new \ReflectionMethod(get_class($this->schema), 'findPrimaryKeyColumns');
        $this->assertEquals([
            $field_name,
        ], $find_primary_key_columns->invoke($this->schema, $table_name_new));
        // Dropping a primary key.
        $this->schema
            ->dropPrimaryKey($table_name_new);
        // Changing a field.
        $field_name_new = 'where';
        $this->schema
            ->changeField($table_name_new, $field_name, $field_name_new, [
            'type' => 'int',
            'not null' => FALSE,
        ]);
        $this->assertFalse($this->schema
            ->fieldExists($table_name_new, $field_name));
        $this->assertTrue($this->schema
            ->fieldExists($table_name_new, $field_name_new));
        // Adding an unique key
        $unique_key_name = $unique_key_introspect_name = 'unique';
        $this->schema
            ->addUniqueKey($table_name_new, $unique_key_name, [
            $field_name_new,
        ]);
        // Check the unique key columns.
        $introspect_index_schema = new \ReflectionMethod(get_class($this->schema), 'introspectIndexSchema');
        $this->assertEquals([
            $field_name_new,
        ], $introspect_index_schema->invoke($this->schema, $table_name_new)['unique keys'][$unique_key_introspect_name]);
        // Dropping an unique key
        $this->schema
            ->dropUniqueKey($table_name_new, $unique_key_name);
        // Dropping a field.
        $this->schema
            ->dropField($table_name_new, $field_name_new);
        $this->assertFalse($this->schema
            ->fieldExists($table_name_new, $field_name_new));
        // Adding an index.
        $index_name = $index_introspect_name = 'index';
        $this->schema
            ->addIndex($table_name_new, $index_name, [
            'update',
        ], $table_specification);
        $this->assertTrue($this->schema
            ->indexExists($table_name_new, $index_name));
        // Check the index columns.
        $this->assertEquals([
            'update',
        ], $introspect_index_schema->invoke($this->schema, $table_name_new)['indexes'][$index_introspect_name]);
        // Dropping an index.
        $this->schema
            ->dropIndex($table_name_new, $index_name);
        $this->assertFalse($this->schema
            ->indexExists($table_name_new, $index_name));
        // Dropping a table.
        $this->schema
            ->dropTable($table_name_new);
        $this->assertFalse($this->schema
            ->tableExists($table_name_new));
    }
    
    /**
     * Tests changing a field length.
     */
    public function testChangeSerialFieldLength() : void {
        $specification = [
            'fields' => [
                'id' => [
                    'type' => 'serial',
                    'not null' => TRUE,
                    'description' => 'Primary Key: Unique ID.',
                ],
                'text' => [
                    'type' => 'text',
                    'description' => 'A text field',
                ],
            ],
            'primary key' => [
                'id',
            ],
        ];
        $this->schema
            ->createTable('change_serial_to_big', $specification);
        // Increase the size of the field.
        $new_specification = [
            'size' => 'big',
            'type' => 'serial',
            'not null' => TRUE,
            'description' => 'Primary Key: Unique ID.',
        ];
        $this->schema
            ->changeField('change_serial_to_big', 'id', 'id', $new_specification);
        $this->assertTrue($this->schema
            ->fieldExists('change_serial_to_big', 'id'));
        // Test if we can actually add a big int.
        $id = $this->connection
            ->insert('change_serial_to_big')
            ->fields([
            'id' => 21474836470,
        ])
            ->execute();
        $id_two = $this->connection
            ->insert('change_serial_to_big')
            ->fields([
            'text' => 'Testing for ID generation',
        ])
            ->execute();
        $this->assertEquals($id + 1, $id_two);
    }

}