The 'Test Connection' button in upload image dialog is displayed only for DC level >= 4.2. However, we can display the 'Test Connection' button for any DC level, as we currently don't test connection to the daemon. I.e. test connection is done by invoking GET on '/info' resource to the proxy service (added in 4.2), which only returns the version of the proxy. (note: we currently require to update the proxy service when upgrading the engine, so we don't need the check if it supports '/info').
*** Bug 1573844 has been marked as a duplicate of this bug. ***
The "Test Connection" button is displayed in both 4.2 and 4.1 DC compatibility version.
Moving to VERIFIED.
This bugzilla is included in oVirt 4.2.4 release, published on June 26th 2018.
Since the problem described in this bug report should be
resolved in oVirt 4.2.4 release, it has been closed with a resolution of CURRENT RELEASE.
If the solution does not work for you, please open a new bug report.