# Author::    Vincent Cuissard  <cuissa_v@epita.fr>
# Copyright:: Copyright (c) 2004, 2005 Uttk team. All rights reserved.
# License::   LGPL
# $Id: /w/fey/uttk/trunk/lib/uttk/strategies/SqlQuery.rb 8789 2005-09-27T14:49:49.088376Z ertai  $


module Uttk

  module Strategies

    #
    # This strategy manage _SQL_ base tests.
    # It use unit testing (EXCEPT ALL query) for checking results.
    # To use it, you need to have _dbi_ installed on your test system
    # and have a database with these things:
    #   * a test schema (MY)
    #   * a reference schema (REF)
    #
    # After that you have just to write all queries that you want to test.
    # Queries will be called on each schema by applying a delta operation:
    #    (REF ` MY) U (MY ` REF).
    #
    # In queries, %s will be replaced by given schemas.
    #

    class SqlQuery < Strategy
      include Concrete

      @@db = nil

      #
      # Methods
      #

      def prologue
        super
        if @@db.nil?
          require 'dbi'
          # Check if driver is available
          if DBI.available_drivers.to_s !~ /#@driver/
            raise_error("Unknown driver: #@driver")
          else
            # Start DB connection
            @@db = DBI.connect("DBI:#@driver:host=#@host;database=#@database",
                               @user, @passwd)
          end
        end
      end
      protected :prologue


      def run_impl
        @delta = nil
        begin
          @delta = perform_delta
        rescue DBI::DatabaseError => ex
          fail(ex)
        end
      end
      protected :run_impl


      def assertion
        unless @delta.nil?
          @log.diff_output = @delta
          fail('Delta not empty')
        end
        super
      end
      protected :assertion


      def perform_delta
        output_a = []
        output_b = []

        # Make queries
        ref_query = @query.gsub(/%s/, @ref_schema)
        my_query = @query.gsub(/%s/, @my_schema)

        # Perform REF ` MY
        @@db.execute("#{ref_query} EXCEPT ALL #{my_query}").fetch do |row|
          output_a << row.join(' | ')
        end

        # Perform MY ` REF
        @@db.execute("#{my_query} EXCEPT ALL #{ref_query}").fetch do |row|
          output_b << row.join(' | ')
        end

        # REF DELTA MY    =>    (REF ` MY) U (MY ` REF) = {}
        # Check this
        return nil if output_a.empty? and output_b.empty?

        # Make report
        { :'REF ` MY' => output_a.join("\n"),
          :'MY ` REF' => output_b.join("\n") }
      end
      private :perform_delta

      #
      # Attributes
      #

      attribute :my_schema,     'Test schema',                   'my'
      attribute :ref_schema,    'Reference schema',              'ref'
      attribute :query,         'SQL query (%s for the schema)', :mandatory
      attribute :driver,        'SQL server driver',             :mandatory
      attribute :database,      'SQL database name',             :mandatory
      attribute :host,          'SQL server host',               :mandatory
      attribute :user,          'SQL user',                      :mandatory
      attribute :passwd,        'SQL pass',                      :mandatory

    end # class SqlQuery

  end # module Strategies

end # module Uttk