[#79] Windows: Fix errors unconvered by E2E tests

Elwig/Windows/MailWindow.xaml.cs

@@ -155,7 +155,7 @@ namespace Elwig.Windows {
         }
 
         protected override async Task OnRenewContext(AppDbContext ctx) {
-            var season = await ctx.Seasons.Include(s => s.PaymentVariants).Where(s => s.Year == Year).SingleAsync();
+            var season = await ctx.Seasons.Include(s => s.PaymentVariants).Where(s => s.Year == Year).SingleOrDefaultAsync();
             var l = new List<string> {
                 MemberDataSheet.Name
             };

Elwig/Windows/MemberAdminWindow.xaml.cs

@@ -388,10 +388,9 @@ namespace Elwig.Windows {
 
             int areaComs = 0, deliveries = 0, credits = 0;
             using (var ctx = new AppDbContext()) {
-                var l = await ctx.FetchMembers(m.MgNr).SingleAsync();
-                areaComs = l.AreaCommitments.Count;
-                deliveries = l.Deliveries.Count;
-                credits = l.Credits.Count;
+                areaComs = await ctx.AreaCommitments.Where(c => c.MgNr == m.MgNr).CountAsync();
+                deliveries = await ctx.Deliveries.Where(d => d.MgNr == m.MgNr).CountAsync();
+                credits = await ctx.Credits.Where(c => c.MgNr == m.MgNr).CountAsync();
             }
             var d = new DeleteMemberDialog(m.MgNr, m.AdministrativeName, areaComs, deliveries, credits);
             if (d.ShowDialog() == true) {

Tests/E2ETests/MemberAdminWindowTest.cs

@@ -80,6 +80,7 @@ namespace Tests.E2ETests {
 
             Window.FindElement(By.WpfId("SaveButton")).Click();
 
+            Thread.Sleep(500);
             Window.FindElement(By.WpfId("SearchInput")).SendKeys("9999");
             Thread.Sleep(500);
             var memberListRow = Window.FindElement(By.WpfId("MemberList")).FindElement(By.ClassName("DataGridRow"));