datatable-argument.md

DataTable Argument Support

Besides primitive types, your scenario step handing method can have an argument of type DataTable. This allows to handle Data Tables defined in the Gherkin feature file.

DataTable is defined under Gherkin.Ast namespace, so make sure to add the using directive for it. Respective Nuget package is already in your project because Xunit.Gherkin.Quick brings it as a dependency.

Example

Gherkin feature file ("./Addition/AddTwoNumbers.feature"):

Feature: AddTwoNumbers
	In order to learn Math
	As a regular human
	I want to add two numbers using Calculator

Scenario: Add various pairs of numbers
	Given following table of 4 inputs and outputs:
		| Number 1 | Number 2 | Result |
		| 1        | 1        | 2      |
		| 10       | 20       | 30     |
		| 10       | 11       | 21     |
		| 111      | 222      | 333    |

Feature class:

[FeatureFile("./Addition/AddTwoNumbers.feature")]
public sealed class AddTwoNumbers : Feature
{
    [Given(@"following table of (\d+) inputs and outputs:")]
    public void Following_table_of_inputs_and_outputs(int inputCount, DataTable dataTable)
    {
        Assert.Equal(inputCount, dataTable.Rows.Count() - 1);

        foreach (var row in dataTable.Rows.Skip(1))
        {
            //arrange.
            var calculator = new Calculator();
            calculator.SetFirstNumber(int.Parse(row.Cells.ElementAt(0).Value));
            calculator.SetSecondNumber(int.Parse(row.Cells.ElementAt(1).Value));

            //act.
            calculator.AddNumbers();

            //assert.
            Assert.Equal(int.Parse(row.Cells.ElementAt(2).Value), calculator.Result);
        }
    }
}

Notes:

• DataTable is a simple class which has rows and cells. Each cell has a value of type String. You will need to convert the values into your desired destination types.
• First row of the received DataTable instance is a header row (at least in this example). Unless you are interested in the column names (or unless you don't put column names into the first row), you will be skipping this row most of the time (dataTable.Rows.Skip(1)).
• DataTable argument needs to be placed after those arguments which receive values from regex groups (matching parentherses) in the method attribute. That's why DataTable is placed after int inputCount argument in the above example - inputCount has a matching regex group expression in the Given attribute - "(\d+)".