If you’re a frequent siesta user, you are probably familiar
with the “callback” parameter – you can find it in almost all common methods
like “click”, “type”, “drag” etc.
Here is the official documentation:
·
callback : Function (optional)
A
function to call after click.
In other words, the callback is a method to be called after
the current operation is complete.
To better understand that let’s stop for a moment and
explain how these common methods behave. When you call the “type” method in
your test code some ‘magic’ happens: the browser will start the operation of typing
as you requested and running the code that should run as a result of this. At
the same time, your test code will continue to run and the next line in
your code will be executed. This is best described as an asynchronous method because
it is running “in the background” while your next line of code is already being
executed.
Now suppose you want a click to be performed after a type
operation. That means that you want the test to “wait” and execute the click
only after the typing operation is complete. In order to do that you need to
provide a function as a callback to the type operation, so when the typing
operation is complete it will call this function which in our examples will
perform the click.
Let’s take a look at some examples:
if you want to run click after type you can provide the
“next” function as a callback in the type method:
t.chain(
function
(next) {
t.type(typeField,'text
to type',next);
},
function
(next) {
t.click(button,
next);
}
);
You can also call the “next” function yourself after a
method that does not have a callback option, like the diag method:
t.chain(
function
(next) {
t.diag('Im
going to click a button!');
next();
},
function
(next) {
t.click(button,
next);
}
);
if you want to write a function of your own which uses the
callback option – for example, a function that clicks on a certain button, you
can write this in your preload file (if you don’t know what a preload file is
or why do you need it – go back to the previous posts):
function clickOnFooButton (t, callback) {
var
fooBtn = Ext.ComponentQuery.query(‘button[itemId=Foo]’);
t.chain(
function (next) {
t.click(fooBtn[0],next)
},
function
(next) {
callback();
}
);
};
And on your test file you can simply call the
“clickOnFooButton” function the same way as you would click on a button:
StartTest(function(t) {
t.chain(
function
(next) {
clickOnFooButton
(t, next);
},
function (next) {
t.type(typeArea,‘hello’);
}
},
function (next) {
t.type(typeArea,‘hello’);
}
);
};
This will make the test to click on the button which has the
itemId of “Foo” and only after that, will type ‘hello’ to the
typeArea.
