Incorrect fetch demand result when internet connection is not available

[linean]

Describe the bug
I have noticed unexpected SDK behavior when I disconnect the device from the network when Prebid ad is auto-refreshing. MediationBannerAdUnit.fetchDemand returns FetchDemandResult.SERVER_ERROR and I think the correct one should be either NETWORK_ERROR or TIMEOUT.

I've checked implementation details and FetchDemandResult is parsed from the error message which in my case is:

SDK internal error: Invalid bid response: Initialization failed: No internet connection detected

I propose we change FetchDemandResult.parseErrorMessage to check if the message contains No internet connection detected and return NETWORK_ERROR.

To Reproduce
Steps to reproduce the behavior:

1. Show Prebid banner with auto refresh enabled
2. Disable network connection
3. Observe FetchDemandResult from `MediationBannerAdUnit.fetchDemand
4. You get FetchDemandResult.SERVER_ERROR suggesting there is some issue with the server

Expected behavior
SDK should return NETWORK_ERROR because the network is not available.

Smartphone

• SDK Version: 2.1.0

[jsligh]

@linean is this still an issue?

[linean]

I don't use Prebid anymore and unfortunately I can't tell. Repro steps are pretty simple, you should be able to reproduce it on your end.