android unit test getStartedActivityIntent always null

I am new at unit test so I am testing a working app that I have to train.

I want to test an Intent that starts an activity at the click of a button.

My method in the test class is :

public void testFindButtonStartsProductDetailActivity (){
        startActivity(mainIntent, null, null);
        final Button findButton = (Button) getActivity().findViewById(com.apps4better.recycle4better.R.id.findButton);

        findButton.performClick();

        final Intent launchIntent = getStartedActivityIntent();
        assertNotNull("launchIntent is null", launchIntent);
}

And the click method in my app looks like this :

public void onClick(View v) {
                // TODO Auto-generated method stub
                //check for network connection before anything
                if (NetworkInspector.haveNetworkConnection(MainActivity.this)){
                    Log.d("Main activity", "giving product id = "+productIdTextField.getText().toString());
                    String a = productIdTextField.getText().toString();
                    long id = Long.valueOf(a).longValue();
                    Intent intent = new Intent(context, ProductDetailActivity.class);
                    intent.putExtra(TAG_PRODUCT_ID, id);
                    intent.putExtra("load_info", true);
                    startActivity(intent);
                }
}

I think the problems comes from the network check that I perform before sending the Intent.

Is it possible that my test method never goes past the Network check? If yes, what it the appropriate solution and a good practice when unit testing ?