Expecta Matchers for FBSnapshotTestCase

Expecta matchers for ios-snapshot-test-case.

Usage

Add Expecta+Snapshots to your Podfile, the latest FBSnapshotTestCase will come in as a dependency.

pod 'Expecta+Snapshots'

App setup

Use expect(view).to.recordSnapshotNamed(@"unique snapshot name") to record a snapshot and expect(view).to.haveValidSnapshotNamed(@"unique snapshot name") to check it.

If you project was compiled with Specta included, you have two extra methods that use the spec hierarchy to generate the snapshot name for you: recordSnapshot() and haveValidSnapshot(). You should only call these once per it() block.

If you need the usesDrawViewHierarchyInRect property in order to correctly render UIVisualEffect, UIAppearance and Size Classes, call [Expecta setUsesDrawViewHierarchyInRect:NO]; inside beforeAll.

#define EXP_SHORTHAND
#include <Specta/Specta.h>
#include <Expecta/Expecta.h>
#include <Expecta+Snapshots/EXPMatchers+FBSnapshotTest.h>
#include "FBExampleView.h"

SpecBegin(FBExampleView)

describe(@"manual matching", ^{

    it(@"matches view", ^{
        FBExampleView *view = [[FBExampleView alloc] initWithFrame:CGRectMake(0, 0, 64, 64)];
        expect(view).to.recordSnapshotNamed(@"FBExampleView");
        expect(view).to.haveValidSnapshotNamed(@"FBExampleView");
    });

    it(@"doesn't match a view", ^{
        FBExampleView *view = [[FBExampleView alloc] initWithFrame:CGRectMake(0, 0, 64, 64)];
        expect(view).toNot.haveValidSnapshotNamed(@"FBExampleViewDoesNotExist");
    });

});

describe(@"test name derived matching", ^{

    it(@"matches view", ^{
        FBExampleView *view = [[FBExampleView alloc] initWithFrame:CGRectMake(0, 0, 64, 64)];
        expect(view).to.recordSnapshot();
        expect(view).to.haveValidSnapshot();
    });

    it(@"doesn't match a view", ^{
        FBExampleView *view = [[FBExampleView alloc] initWithFrame:CGRectMake(0, 0, 64, 64)];
        expect(view).toNot.haveValidSnapshot();
    });

});

SpecEnd

Approximation support

If for some reason you want to specify a tolerance for your test, you can use either named or unnamed matchers, where the tolerance parameter is a CGFloat in the interval [0, 1] and it represents the minimum ratio of unmatched points by the total number of points in your snapshot. In the example below, a tolerance of 0.01 means our view could be up to 1% different from the reference image.

expect(view).to.haveValidSnapshotWithTolerance(0.01);
expect(view).to.haveValidSnapshotNamedWithTolerance(@"unique snapshot name", 0.01);

Sane defaults

EXPMatchers+FBSnapshotTest will automatically figure out the tests folder, and add a reference image directory, if you'd like to override this, you should include a beforeAll block setting the setGlobalReferenceImageDir in each file containing tests.

beforeAll(^{
    setGlobalReferenceImageDir(FB_REFERENCE_IMAGE_DIR);
});

Example

A complete project can be found in FBSnapshotTestCaseDemo.

Notably, take a look at FBSnapshotTestCaseDemoSpecs.m for a complete example, which is an expanded Specta version version of FBSnapshotTestCaseDemoTests.m.

Finally you can consult the tests for ARTiledImageView or NAMapKit.

License

MIT, see LICENSE