Question

I have a service that uses Groovy SQL to make some sql calls to the database. My tests for this service are failing because dataSource is null. How do I get dataSource to be the appropriate connection inside a unit test?

ExampleService.groovy

class ExampleService { 
    def dataSource 

    def getSQL() { 
        def sql = new Sql(dataSource) 
        def query = "some query" 
        sql.call(query) 
        sql.close() 
    } 
} 

ExampleServiceTests.groovy

@TestFor(ExampleService) 
class ExampleServiceTests { 
    void testExample() { 
        def es = new ExampleService() 
        es.getSQL() 
    } 
} 

In the above example I get the following error:

java.lang.NullPointerException: Must specify a non-null Connection

Answer 1

There’s no database in unit tests, only in integration tests. Everything in unit tests uses mocking since there’s no active Spring, Hibernate, database, plugins, etc. Persistence should always be tested against a database, even if it’s just the in-memory HSQL or H2 database, or a dev version of a MySQL/Postgres/Oracle/etc. database.