Unable to fetch Resource from AemContext : Mockito

Hi,

I am new to Mockito. I am trying to write test case for one of the model class.

Here I am using AemContext (io.wcm.testing.mock.aem.junit.AemContext) for initializing the resourceResolver finally fetching the resource.

I am able to get the resource resolver object from AemContext, but then unable to create a test resource using the below code.

private ResourceResolver resResolver;

@Rule

public final AemContext context = new AemContext(ResourceResolverType.RESOURCERESOLVER_MOCK);

resResolver = context.resourceResolver(); //output : org.apache.sling.testing.resourceresolver.MockResourceResolver@4923ab24

resResolver.create(resResolver.getResource("/tmp"), "testpage", Collections.<String, Object> emptyMap()); // throws null pointer exception.

Can someone please guide me how to create resource for unit test cases.