Cucumber 步骤中传Data Table作为参数

引用链接：http://cukes.info/step-definitions.html

Data Tables

Data Tables are handy for specifying a larger piece of data:

Given the following users exist:
  | name  | email           | phone |
  | Aslak | aslak@email.com | 123   |
  | Matt  | matt@email.com  | 234   |
  | Joe   | joe@email.org   | 456   | 

Just like Doc Strings, they will be passed to the Step Definition as the last argument:

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@Given("^the following users exist$")
public void the_following_users_exist(DataTable users) {
    // Save them in the database
}

See the DataTable API docs for details about how to access data in the table.

Substitution in Scenario Outlines

If you use a DocString or DataTable argument in steps in Scenario Outlines, any < > delimited tokens will be substituted with values from the example tables. For example:

Scenario Outline: Email confirmation
  Given I have a user account with my name "Jojo Binks"
When an Admin grants me <Role> rights
Then I should receive an email with the body:
"""
    Dear Jojo Binks,
    You have been granted <Role> rights.  You are <details>. Please be responsible.
    -The Admins
"""
Examples:
    |  Role     | details                                         |
    |  Manager  | now able to manage your employee accounts       |
    |  Admin    | able to manage any user account on the system   |

Data Table diffing

One very powerful feature in Cucumber is comparison of tables. You can compare a table argument to another table that you provide within your step definition. This is something you would typically do in a Then step, and the other table would typically be constructed programmatically from your application’s data.

Beware that the diffing algorithm expects your data to be column-oriented, and that the first row of both tables represents column names. If your tables don’t have some similarity in the first row you will not get very useful results. The column names must be unique for each column – and they must match.

Here is an example of a Data Table that wi want to diff against actual results:

Then I should see the following cukes:
  | Latin           | English      |
  | Cucumis sativus | Cucumber     |
  | Cucumis anguria | Burr Gherkin |

A Step Definition can diff the DataTable with data pulled out of your application, for example from a Web page or a Database:

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@Then("^I should see the following cukes:$")
public void the_following_users_exist(DataTable expectedCukesTable) {
    // We'd typically pull this out of a database or a web page...
    List<Cuke> actualCukes = new ArrayList();
    actualCukes.add(new Cuke("Cucumis sativus", "Concombre"));
    actualCukes.add(new Cuke("Cucumis anguria", "Burr Gherkin")); 
    
    expectedCukesTable.diff(actualCukes)
}

The list passed to diff can be a DataTable, List<YourType>, List<Map> or a List<List<ScalarType>>.

If the tables are different, an exception is thrown, and the diff of the two tables are reported in the Report.

String Transformations

Cucumber provides an API that lets you take control over how strings are converted to other types. This is useful especially for dynamically typed languages, but also for statically typed languages when you need more control over the transformation.

Let’s consider a common example - turning a string into a date:

Given today's date is "10-03-1971"

First of all, this might mean the 10th of March in some countries, and the 3rd of October in others. It’s best to be explicit about how we want this converted. We’ll try to convert it to 10th of March 1971.

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Cucumber-JVM knows how to convert strings into various scalar types. A scalar type is a type that can be derived from a single string value. Cucumber-JVM's built-in scalar types are numbers, enums, java.util.Date, java.util.Calendar and arbitrary types that have a single-argument constructor that is either a String or an Object.

Transformation to java.util.Date and java.util.Calendar will work out-of-the-box as long as the string value matches one of the SHORT, MEDIUM, FULL or LONG formats defined by java.util.DateFormat.

It turns out that 10-03-1971 from our example doesn't match any of those formats, so we have to give Cucumber a hint:

@Given("today's date is "(.*)"")
public void todays_date_is(@Format("dd-MM-yyyy") Date today) {
}

Many Java programmers like to use Joda Time. Cucumber-JVM doesn't have any special support for Joda Time, but since Joda's LocalDate has a LocalDate(Object) constructor it is considered a scalar by default.

However, in this case it wouldn't also know how to pass the _format_ string, so you would get an exception when Cucumber instantiates it with new LocalDate("10-03-1971").

A custom formatter gives you full control:

@Given("today's date is "(.*)"")
public void todays_date_is(
  @Format("dd-MM-yyyy") 
  @Transform(JodaTransformer.class) 
  LocalDate today) {
}

The custom transformer looks like this:

public class JodaTransformer extends Transformer<LocalDate> {
    @Override
    public LocalDate transform(String value) {
        String format = getParameterInfo().getFormat();
        DateTimeFormatter dateTimeFormatter = DateTimeFormat.forStyle(format);
        dateTimeFormatter = dateTimeFormatter.withLocale(getLocale());
        return dateTimeFormatter.parseLocalDate(value);
    }
}

Of course, you can write transformers for anything, not just dates.

Data Table Transformations

This applies to Cucumber-JVM only

Data Tables can be transformed to a List of various types. We’ll see how the table in the following Scenario can be transformed to different kinds of lists.

Scenario: Some vegetables
  Given I have these vegetables:
    | name     | color |
    | Cucumber | Green |
    | Tomato   | Red   |

List of YourType

The table can be transformed into a list of vegetables:

public class Vegetable {
    public String name;
    public Color color; // Color is an enum
}

The Step Definition:

@Given("I have these vegetables:")
public void I_have_these_vegetables(List<Vegetable> vegetables) {
    // Do something with the vegetables
}

The header row is used to name fields in the generic List type.

IMPORTANT: If the generic List type (Vegetable in this case) is a scalar (i.e. it has a String or Object constructor), the header will not be used to name fields in the class. Instead you would get a List that has one Vegetable for each cell (6 in this case). See List of Scalar below.

List of Map

You can also transform a DataTable to a list of maps:

@Given("I have these vegetables:")
public void I_have_these_vegetables(List<Map<String, String>> vegetables) {
    // Do something with the vegetables
}

The Key and Value generic types of the Map can be any kind of scalar type.

List of List of scalar

You can also convert it to a list of list scalar:

@Given("I have these vegetables:")
public void I_have_these_vegetables(List<List<String>> vegetables) {
    // Do something with the vegetables
}

This will convert it to a flattened list like this:

[["name", "color"], ["Cucumber", "Green"], ["Tomato", "Red"]]

You can also convert it to a list of scalar:

List of scalar

@Given("I have these vegetables:")
public void I_have_these_vegetables(List<String> vegetables) {
    // Do something with the vegetables
}

This will convert it to a flattened list like this: ["name", "color", "Cucumber", "Green", "Tomato", "Red"]