Test class for Custom Metadata Types [duplicate]

Question

I have a custom metadata type with one field(text) which holds a single value. I am referring this field value in the Lightning Component to pass it as a URL. Apex controller:

@AuraEnabled
public static String getLogoutUrl() {
    List<Portal_Metadata__mdt> testUrl = 
        [Select Id, Portal_URL__c from Portal_Metadata__mdt LIMIT 1];   
    return testUrl[0].Portal_URL__c;  
}

In Component's JS, I have configured to get this value when I have:

window.location.href = myUrl;

How could I write a unit test for this Custom metadata type?

Answer 1

I've had success with mocking when testing interactions between configuration and code which are difficult to control. Consider a structure like the following:

public virtual class PortalMetadata
{
    static PortalMetadata service = new PortalMetadata();
    @TestVisible void setMock(PortalMetadata mock) { service = mock; }

    public static List<MyMetadata__mdt> getAll() { return service.getAll(); }

    protected virtual List<MyMetadata__mdt> getAll()
    {
        return [SELECT Portal_Url__c FROM MyMetadata__mdt];
    }
}

Okay, so now you can mock out which records get returned, but how can you specify your own metadata records? Well, serialization has been a useful trick for me lately and comes in handy again here:

Map<String, Object> data = new Map<String, Object>
{
    'Portal_Url__c' => 'someUrl'
};
MyMetadata__mdt metadataRecord = (MyMetadata__mdt)JSON.deserialize(
    JSON.serialize(data), MyMetadata__mdt.class
);

How does the above help you test? Well, now you can set up your own mock metadata and have complete control over what gets "queried":

@IsTest
class testMyClass
{
    static final String URL = 'some_url_here';

    class PortalMetadataMock extends PortalMetadata
    {
        protected override List<MyMetadata__mdt> getAll()
        {
            Map<String, Object> data = new Map<String, Object> { 'Portal_Url__c' => URL };
            return new List<MyMetadata__mdt>
            {
                (MyMetadata__mdt)JSON.deserialize(
                    JSON.serialize(data), MyMetadata__mdt.class
                )
            };
        }
    }

    static testmethod void testGetLogoutUrl()
    {
        Test.startTest();
            PortalMetadata.setMock(new PortalMetadataMock());
            String retrievedUrl = MyClass.getLogoutUrl();
        Test.stopTest();

        system.assertEquals(URL, retrievedUrl, 'Assertion message here');
    }
}