# When CouchDB view functions get complex, it's nice to be able to unit test them.<\/span>\n# When your development dataset is large, and views take some time to build, better<\/span>\n# to find bugs via unit tests over having to wait for a view build to see if things<\/span>\n# are working correctly.<\/span>\n\n# This implementation uses Johnson for executing Javascript -- see the evaluate_map method<\/span>\n# at the end of this file. Note that we can define the emit and log functions as Ruby Proc <\/span>\n# objects and have them work in the Javascript context. Pretty cool.<\/span>\n\n# I think it would be possible to test show and list functions as well, using a similar<\/span>\n# technique to mock out the getRow() and send() functions.<\/span>\nrequire<\/span> 'rubygems'<\/span>\nrequire<\/span> "johnson"<\/span>\nrequire<\/span> "json"<\/span>\nrequire<\/span> "test/unit"<\/span>\n\n# Johnson monkeypatch, so that assert_equal works as expected with array values<\/span>\nclass<\/span> Johnson<\/span>::<\/span>SpiderMonkey<\/span>::<\/span>RubyLandProxy<\/span>\n  def<\/span> ==<\/span>(<\/span>other<\/span>)<\/span>\n    case<\/span> other<\/span>\n    when<\/span> Array<\/span>\n      to_a<\/span> ==<\/span> other<\/span>\n    else<\/span>\n      super<\/span>\n    end<\/span>\n  end<\/span>\nend<\/span>\n\nclass<\/span> TestViews<\/span> <<\/span> Test<\/span>::<\/span>Unit<\/span>::<\/span>TestCase<\/span>\n\n  def<\/span> setup<\/span>\n    # Set the design doc in an instance variable. In practice, you'll want to get the <\/span>\n    # design doc from the server using your preferred HTTP client, ex:<\/span>\n    # <\/span>\n    #   @ddoc = JSON.parse RestClient.get('localhost:5984/mydb/_design/myapp')<\/span>\n    #<\/span>\n    # If you're getting the same ddoc again and again for each test, you can store it in a<\/span>\n    # class variable or constant on test suite startup, thus avoiding the overhead of <\/span>\n    # HTTP and JSON parsing of the ddoc for each test.<\/span>\n    @ddoc<\/span> =<\/span> JSON<\/span>.<\/span>parse<\/span>(<\/span><<-<\/span>EOV<\/span>)<\/span>\n      {<\/span>\n        "_id": "_design/myapp",<\/span>\n        "views": {<\/span>\n          "by_city": {<\/span>\n            "map": "function(doc) { emit([doc.city, doc.name], doc); }"<\/span>\n          }<\/span>\n        }<\/span>\n      }<\/span>\n    EOV<\/span>\n  end<\/span>\n\n  def<\/span> test_by_city<\/span>\n    mapfun<\/span> =<\/span> @ddoc<\/span>[<\/span>'views'<\/span>][<\/span>'by_city'<\/span>][<\/span>'map'<\/span>]<\/span>\n    doc<\/span> =<\/span> {<\/span>"name"<\/span> =><\/span> "Geoff"<\/span>,<\/span> "city"<\/span> =><\/span> "Chicago"<\/span>,<\/span> "state"<\/span> =><\/span> "IL"<\/span>}<\/span>\n    \n    rows<\/span> =<\/span> evaluate_map<\/span>(<\/span>mapfun<\/span>,<\/span> doc<\/span>)<\/span>[<\/span>'rows'<\/span>]<\/span>\n    \n    assert_equal<\/span> 1<\/span>,<\/span> rows<\/span>.<\/span>size<\/span>\n    assert_equal<\/span> [<\/span>"Chicago"<\/span>,<\/span> "Geoff"<\/span>]<\/span>,<\/span> rows<\/span>.<\/span>first<\/span>[<\/span>'key'<\/span>]<\/span>\n    assert_equal<\/span> doc<\/span>,<\/span> rows<\/span>.<\/span>first<\/span>[<\/span>'value'<\/span>]<\/span>\n  end<\/span>\n  \n\n  private<\/span>\n    def<\/span> evaluate_map<\/span>(<\/span>fun<\/span>,<\/span> doc<\/span>)<\/span>\n      rows<\/span>,<\/span> log<\/span> =<\/span> []<\/span>,<\/span> []<\/span>\n      emitfun<\/span> =<\/span> Proc<\/span>.<\/span>new<\/span> {<\/span>|<\/span>k<\/span>,<\/span> v<\/span>|<\/span> rows<\/span> <<<\/span> {<\/span>"key"<\/span> =><\/span> k<\/span>,<\/span> "value"<\/span> =><\/span> v<\/span>}}<\/span>\n      logfun<\/span> =<\/span> Proc<\/span>.<\/span>new<\/span> {<\/span>|<\/span>m<\/span>|<\/span> log<\/span> <<<\/span> m<\/span>}<\/span>\n      map<\/span> =<\/span> Johnson<\/span>.<\/span>evaluate<\/span>(<\/span>fun<\/span>,<\/span> :emit<\/span> =><\/span> emitfun<\/span>,<\/span> :log<\/span> =><\/span> logfun<\/span>)<\/span>\n      map<\/span>.<\/span>call<\/span>(<\/span>doc<\/span>)<\/span>\n      {<\/span>"rows"<\/span> =><\/span> rows<\/span>,<\/span> "log"<\/span> =><\/span> log<\/span>}<\/span>\n    end<\/span>\nend<\/span>\n<\/pre><\/div>\n