HandleCreateGroupSuccessfully creates an HTTP handler at `/groups` on the test handler mux that tests group creation.

HandleDeleteGroupSuccessfully creates an HTTP handler at `/groups` on the test handler mux that tests group deletion.

HandleGetGroupSuccessfully creates an HTTP handler at `/groups` on the test handler mux that responds with a single group.

HandleListGroupsSuccessfully creates an HTTP handler at `/groups` on the test handler mux that responds with a list of two groups.

HandleUpdateGroupSuccessfully creates an HTTP handler at `/groups` on the test handler mux that tests group update.

CreateRequest provides the input to a Create request.

GetOutput provides a Get result.

ListOutput provides a single page of Group results.

UpdateOutput provides an update result.

UpdateRequest provides the input to as Update request.

ExpectedGroupsSlice is the slice of groups expected to be returned from ListOutput.

FirstGroup is the first group in the List request.

SecondGroup is the second group in the List request.

SecondGroupUpdated is how SecondGroup should look after an Update.