How to simulate table view or collection view scrolling using Subliminal?

Question

I'm currently trying both KIF and Subliminal for iOS integration testing. But I still cannot figure out how to simulate scrolling on table view or collection view using both frameworks. Like how to scroll to the bottom of table view or collection view.

EDIT 1:

I made simple single collection view app here https://github.com/nicnocquee/TestSubliminal

Basically I want to test the last cell's label. I cannot do

SLElement *lastLabel = [SLElement elementWithAccessibilityLabel:@"Label of the last cell"];
[lastLabel scrollToVisible];

because the label doesn't exist yet until the collection view is scrolled to the bottom.

EDIT 2:

I marked Aaron's answer as the answer. But Jeffrey's also works :)

Answer 1

You could also simulate the user scrolling through the collection looking for the cell, by dragging the collection view until the cell becomes visible:

while (!SLWaitUntilTrue([UIAElement(lastLabel) isValidAndVisible], 1.0)) {
    [[SLWindow mainWindow] dragWithStartOffset:CGPointMake(0.5, 0.75) endOffset:CGPointMake(0.5, 0.25)];
}

Those offsets translate to dragging straight up along the middle of the collection view, from 75% down the view to 25% down the view. -isValidAndVisible lets you check for the cell's visibility without worrying about whether it exists yet (whereas -isVisible would throw an exception if the cell didn't exist). And I wrap -isValidAndVisible in SLWaitUntilTrue so that we let the collection view finish scrolling before dragging again.

In contrast to @AaronGolden's app hook solution, this approach requires you be able to identify a particular cell to scroll to. So I'd frame this approach as "scroll to a cell", whereas the app hook lets you "scroll to a position".

Answer 2

This is probably more invasive but so simple too - Go to SLUIAElement.m and add the following methods:

- (void)scrollDown {
[self waitUntilTappable:NO thenSendMessage:@"scrollDown()"];
}


- (void)scrollUp {
[self waitUntilTappable:NO thenSendMessage:@"scrollUp()"];
}

You will also have to declare those method signature in the SLUIAElement.h file to make those new methods visible to the test suite.

Then what you can do is add an accessibility identifier to a collection view, call that identifier and scroll on it. EXAMPLE:

SLElement *scrollView = [SLElement elementWithAccessibilityIdentifier:@"scrollView"];

[scrollView scrollDown];

Answer 3

The issue is that the cell you're trying to find in your test case, the one with label "This is cell 19", does not exist until the collection view has already been scrolled. So we need to make the view scroll first and then look for the cell. The easiest way to make the collection view scroll with Subliminal is through an application hook. In (for example) your view controller's viewDidLoad method, you could register the view controller to respond to a particular message from any Subliminal test case, like so:

[[SLTestController sharedTestController] registerTarget:self forAction:@selector(scrollToBottom)];

and the view controller could implement that method as:

- (void)scrollToBottom {
    [self.collectionView setContentOffset:CGPointMake(0.0, 1774.0)];
}

That 1774 is just the offset that happens to scroll the collection view in your test app all the way to the bottom. In a real application the app hook would probably be more sophisticated. (And in a real application you would want to make sure to call [[SLTestController sharedTestController] deregisterTarget:self] in your view controller's dealloc method.)

To trigger the scrollToBottom method from a Subliminal test case you can use:

[[SLTestController sharedTestController] sendAction:@selector(scrollToBottom)];

or the convenience macro:

SLAskApp(scrollToBottom);

The shared SLTestController will send the scrollToBottom message to the object that registered to receive it (your view controller).

When the sendAction or SLAskApp macro returns your cell 19 will already be visible, so you don't need to bother with the [lastLabel scrollToVisible] call anymore. Your complete test case could look like this:

- (void)testScrollingCase {
    SLElement *label1 = [SLElement elementWithAccessibilityLabel:@"This is cell 0"];
    SLAssertTrue([UIAElement(label1) isVisible], @"Cell 0 should be visible at this point");

    SLElement *label5 = [SLElement elementWithAccessibilityLabel:@"This is cell 5"];
    SLAssertFalse([UIAElement(label5) isValid], @"Cell 5 should not be visible at this point");

    // Cause the collection view to scroll to the bottom.
    SLAskApp(scrollToBottom);

    SLElement *lastLabel = [SLElement elementWithAccessibilityLabel:@"This is cell 19"];
    SLAssertTrue([UIAElement(lastLabel) isVisible], @"Last cell should be visible at this point");
}