actionscript-3apache-flexflex4.5flexunit4

Writing a parameterized test fails with: There was an error retrieving the parameters for the testcase: cause invalid value for parameterized field


I have a few unit tests that require very large strings for the test data. I do not want to declare the HTML string in the test itself as this can obscure that actual test. Rather, I would like to load these strings from an external resource for each test.

Though I am not running the same test with different sets of data, parameterized tests looks to be a viable solution; however, I am having difficulty getting the following example to work.

Note: This code is based on the TestNG example.

package flexUnitTests
{
    import helpers.HTMLDataHelper;

    import org.flexunit.runners.Parameterized;
    import org.hamcrest.assertThat;
    import org.hamcrest.text.containsString;

    [RunWith("org.flexunit.runners.Parameterized")]
    public class SimpleTestCase
    {
        private var parameterized:Parameterized;

        public static var dataLoader:HTMLDataHelper = new HTMLDataHelper("data/layer.html");

        [DataPoint(loader="dataLoader")]
        public static var htmlContent:String;

        [Test(dataprovider="htmlContent", description="Tests something.")]
        public function mustPassThisSimpleTest(htmlContentParam:String):void
        {
            assertThat(htmlContentParam, containsString("head"));
        }
    }
}

When I run this test I receive the following error message:

Error: There was an error retrieving the parameters for the testcase: cause invalid value for parameterized field htmlContent: null

Any thoughts as to what might be the solution to this problem might be?


Solution

  • One solution I found was to run the tests in the class with the Theories runner as shown below.

    package flexUnitTests
    {
        import helpers.HTMLDataHelper;
    
        import org.flexunit.experimental.theories.Theories;
        import org.flexunit.runners.Parameterized;
        import org.hamcrest.assertThat;
        import org.hamcrest.object.equalTo;
        import org.hamcrest.text.containsString;
    
        [RunWith("org.flexunit.experimental.theories.Theories")]
        public class SimpleTestCase
        {
            public static var dataLoader:HTMLDataHelper = new HTMLDataHelper("data/layer.html");
    
            [DataPoint(loader="dataLoader")]
            public static var htmlContent:String;
    
            [Test(dataprovider="htmlContent", description="Tests something.")]
            public function mustPassThisSimpleTest(htmlContentParam:String):void
            {
                assertThat(htmlContentParam, containsString("head"));
            }
        }
    }
    

    However the side effect is that all of your tests within the test class will display cryptic error messages when the tests fail. For example,

    Error: mustWorkWithRegularTests

    instead of the much more useful

    Error: Expected: a string containing "head"
    but: was "this is some text"
    

    Though this does "solve" the problem I was having, IMHO the trade off in message clarity is not worth being able to load data from external sources.