Using Slim Scenario fixtures this can be implemented fairly easy. Scenarios are Slim tables that can be called form other Slim tables. For a step by step tutorial on how to apply Scenarios I recommend watching Bob Martin’s screencast.

With a few additions to Bob Martin’s video you can use that test for both API and UI.

Lets say we have the following BDD style test:

given a current maximum capacity of 2 and 1 items already planned
then I can lower the maximum capacity to 1
then I can not lower the maximum capacity to 0

Using scenarios this would end up in the following FitNesse markup:

!|scenario|given a current maximum capacity of |maxCapacity| and |itemsPlanned| items already planned|
|set maximum capacity to|@maxCapacity|
|plan|@itemsPlanned|items|

!|scenario|then I can lower the maximum capacity to|newMaxCapacity|
|ensure|set maximum capacity to|@newMaxCapacity|

!|scenario|then I can not lower the maximum capacity to|newMaxCapacity|
|reject|set maximum capacity to|@newMaxCapacity|

!|script|MaxCapacityApiDriver|

!|script|
|given a current maximum capacity of |2| and |1| items already planned|
|then I can lower the maximum capacity to |1|
|then I can not lower the maximum capacity to |0|

And the fixture would look like this:

public class MaxCapacityApiDriver {

	private Capacity capacity = new Capacity();

	public boolean setMaximumCapacityTo(int max) {
		try {
			capacity.setMax(max);
			return true;
		} catch(MoreItemsThanCapacityException e) {
			return false;
		}
	}

	public void planItems(int items) {
		for(int x=0; x<items; x++) {
			capacity.plan();
		}
	}
}

Now if we look at the example we could also apply this to our maintenance user interface where the admin can actually change the max capacity.

Using selenium-rc this can be implemented fairly easy. I choose to keep the FitNesse pages the same, the only thing I change is the driver that is used.

Step 1. Extract Scenario

we do not want to duplicate the scenarios so we extract the scenarios to a seperate page. We can then include this page using the !include directive in FitNesse.

Our test FitNesse markup now looks like this:

!include ScenarioPage

!|script|MaxCapacityApiDriver|

!|script|
|given a current maximum capacity of |2| and |1| items already planned|
|then I can lower the maximum capacity to |1|
|then I can not lower the maximum capacity to |0|

Step 2. Extract Test

Wait a minute. We also want to reuse our BDD style test. Let’s do the same trick as we did using the ScenarioPage.

After extracting the Test our FitNesse markup looks like this:

!include ScenarioPage

!|script|MaxCapacityApiDriver|

!include TestPage

Step 3. Implement Driver

Now all we have to do is implement the UI driver.

!include ScenarioPage

!|script|MaxCapacityUiDriver|

!include TestPage

This is how the fixture code could look like using selenium-rc, I left out some plumbing for readability

public class MaxCapacityUiDriver {

	private Selenium selenium;

	public boolean setMaximumCapacityTo(int max) {
		selenium.open("/capacity/change");
		selenium.type("maximum", String.valueOf(max));
		selenium.click("changeMaxButton");
		selenium.waitForPageToLoad(TIMEOUT);
		return selenium.isTextPresent("successfully changed capacity to: "
				+ max);
	}

	public void planItems(int items) {
		selenium.open("/items");
		for (int x = 0; x < items; x++) {
			selenium.click("planItem");
			selenium.waitForPageToLoad(TIMEOUT);
		}
	}
}

Using FitNesse scenarios and extracting pages to include them is very handy when you want to re-use some tests. Please keep in mind that it is not wise to test your application code through your UI, so apply this carefully. I tend to pick only a few scenarios to see if the UI and API communicate properly.