test_unit_examples_test.rdoc

Path: doc/examples/test_unit_examples_test.rdoc
Last Update: Mon May 20 13:49:39 +0000 2013

FlexMock Examples

    require 'flexmock/test_unit'

    class TestSimple < Test::Unit::TestCase

      # Simple stubbing of some methods

      def test_simple_mock
        m = flexmock(:pi => 3.1416, :e => 2.71)
        assert_equal 3.1416, m.pi
        assert_equal 2.71, m.e
      end
    end

    class TestUndefined < Test::Unit::TestCase

      # Create a mock object that returns an undefined object for method calls

      def test_undefined_values
        m = flexmock("mock")
        m.should_receive(:divide_by).with(0).
          and_return_undefined
        assert_equal FlexMock.undefined, m.divide_by(0)
      end
    end

    class TestDb < Test::Unit::TestCase

      # Expect multiple queries and a single update

      # Multiple calls to the query method will be allows, and calls may
      # have any argument list. Each call to query will return the three
      # element array [1, 2, 3]. The call to update must have a specific
      # argument of 5.

      def test_db
        db = flexmock('db')
        db.should_receive(:query).and_return([1,2,3])
        db.should_receive(:update).with(5).and_return(nil).once

        # Test Code

        db.query
        db.update(5)
      end
    end

    class TestOrdered < Test::Unit::TestCase

      # Expect all queries before any updates

      # All the query message must occur before any of the update
      # messages.

      def test_query_and_update
        db = flexmock('db')
        db.should_receive(:query).and_return([1,2,3]).ordered
        db.should_receive(:update).and_return(nil).ordered

        # test code here

        db.query
        db.update
      end
    end

    class MoreOrdered < Test::Unit::TestCase

      # Expect several queries with different parameters

      # The queries should happen after startup but before finish. The
      # queries themselves may happen in any order (because they are in
      # the same order group). The first two queries should happen exactly
      # once, but the third query (which matches any query call with a
      # four character parameter) may be called multiple times (but at
      # least once). Startup and finish must also happen exactly once.

      # Also note that we use the <code>with</code> method to match
      # different argument values to figure out what value to return.

      def test_ordered_queries
        db = flexmock('db')
        db.should_receive(:startup).once.ordered
        db.should_receive(:query).with("CPWR").and_return(12.3).
          once.ordered(:queries)
        db.should_receive(:query).with("MSFT").and_return(10.0).
          once.ordered(:queries)
        db.should_receive(:query).with(/^....$/).and_return(3.3).
          at_least.once.ordered(:queries)
        db.should_receive(:finish).once.ordered

        # Test Code

        db.startup
        db.query("MSFT")
        db.query("XYZY")
        db.query("CPWR")
        db.finish
      end
    end

    class EvenMoreOrderedTest < Test::Unit::TestCase

      # Same as above, but using the Record Mode interface

      # The record mode interface offers much the same features as the
      # <code>should_receive</code> interface introduced so far, but it
      # allows the messages to be sent directly to a recording object
      # rather than be specified indirectly using a symbol.

      def test_ordered_queries_in_record_mode
        db = flexmock('db')
        db.should_expect do |rec|
          rec.startup.once.ordered
          rec.query("CPWR") { 12.3 }.once.ordered(:queries)
          rec.query("MSFT") { 10.0 }.once.ordered(:queries)
          rec.query(/^....$/) { 3.3 }.at_least.once.ordered(:queries)
          rec.finish.once.ordered
        end

        # Test Code

        db.startup
        db.query("MSFT")
        db.query("XYZY")
        db.query("CPWR")
        db.finish
      end
    end

    class RecordedTest < Test::Unit::TestCase

      # Using Record Mode to record a known, good algorithm for testing

      # Record mode is nice when you have a known, good algorithm that can
      # use a recording mock object to record the steps. Then you compare
      # the execution of a new algorithm to behavior of the old using the
      # recorded expectations in the mock. For this you probably want to
      # put the recorder in _strict_ mode so that the recorded
      # expectations use exact matching on argument lists, and strict
      # ordering of the method calls.

      # <b>Note:</b> This is most useful when there are no queries on the
      # mock objects, because the query responses cannot be programmed
      # into the recorder object.

      def test_build_xml
        builder = flexmock('builder')
        builder.should_expect do |rec|
          rec.should_be_strict
          known_good_way_to_build_xml(rec)  # record the messages
        end
        new_way_to_build_xml(builder)       # compare to new way
      end

      def known_good_way_to_build_xml(builder)
        builder.person
      end

      def new_way_to_build_xml(builder)
        builder.person
      end

    end

    class MultipleReturnValueTest < Test::Unit::TestCase

      # Expect multiple calls, returning a different value each time

      # Sometimes you need to return different values for each call to a
      # mocked method. This example shifts values out of a list for this
      # effect.

      def test_multiple_gets
        file = flexmock('file')
        file.should_receive(:gets).with_no_args.
          and_return("line 1\n", "line 2\n")

        # test code here

        file.gets                   # returns "line 1"
        file.gets                   # returns "line 2"
      end
    end

    class IgnoreUnimportantMessages < Test::Unit::TestCase

      # Ignore uninteresting messages

      # Generally you need to mock only those methods that return an
      # interesting value or wish to assert were sent in a particular
      # manner. Use the <code>should_ignore_missing</code> method to turn
      # on missing method ignoring.

      def test_an_important_message
        m = flexmock('m')
        m.should_receive(:an_important_message).and_return(1).once
        m.should_ignore_missing

        # Test Code

        m.an_important_message
        m.an_unimportant_message
      end

      # When <code>should_ignore_missing</code> is enabled, ignored
      # missing methods will return an undefined object. Any operation on
      # the undefined object will return the undefined object.

    end

    class PartialMockTest < Test::Unit::TestCase

      # Mock just one method on an existing object

      # The Portfolio class calculate the value of a set of stocks by
      # talking to a quote service via a web service. Since we don't want
      # to use a real web service in our unit tests, we will mock the
      # quote service.

      def test_portfolio_value
        flexmock(QuoteService).new_instances do |m|
          m.should_receive(:quote).and_return(100)
        end
        port = Portfolio.new
        value = port.value     # Portfolio calls QuoteService.quote
        assert_equal 100, value
      end

      class QuoteService
      end

      class Portfolio
        def value
          qs = QuoteService.new
          qs.quote
        end
      end
    end

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