Unit Test for Salesforce Rest API

• Any test class should be annotated with @isTest annotation.
• Test method will have an identifier as testmethod as part of the method declaration.
• To test Rest api RestRequest and RestResponse object to be instantiated and added in RestContext instance
• Invoke Rest Api class to get back the response.

Example shown below:

@isTest

private class RestApiSample_Test {

    static testMethod void testGetMethod() {

        RestRequest req = new RestRequest(); 

        RestResponse res = new RestResponse(); 

        

        req.requestURI = '/services/apexrest/RestApiSample'; 

        req.addParameter('userName', 'Raghav');

        req.httpMethod = 'GET';

        RestContext.request = req;

        RestContext.response = res;

        String msg = RestApiSample.getWelcomeMessage();

        system.assertEquals(msg, 'Welcome Raghav');

    }

}