fix(notification): enable web smtp test with saved password

Allow Web SMTP egress on TCP 587 and reuse the saved channel password only when connection settings match.

Ref: IT-1601

HrynCo.NotificationService.Web.IntegrationTests/AdminSmtpTestControllerTests.cs

@@ -0,0 +1,112 @@
+using System.Reflection;
+using System.Text.Json;
+using HrynCo.NotificationService.DAL.Abstract.Providers;
+using HrynCo.NotificationService.Web.Controllers.Admin;
+using MediatR;
+using Microsoft.AspNetCore.Mvc;
+
+namespace HrynCo.NotificationService.Web.IntegrationTests;
+
+public sealed class AdminSmtpTestControllerTests
+{
+    private static readonly Guid ChannelId = Guid.NewGuid();
+
+    [Fact]
+    public async Task BlankPasswordUsesSavedSecretAndCurrentUnsavedSender()
+    {
+        var (controller, recorder) = CreateController();
+        var response = await controller.TestSmtp(Request(), CancellationToken.None);
+
+        Assert.True(Succeeded(response));
+        Assert.Equal("saved-test-secret", recorder.SentCommand?.Password);
+        Assert.Equal("changed@example.invalid", recorder.SentCommand?.FromEmail);
+        Assert.Equal("Changed sender", recorder.SentCommand?.FromName);
+        Assert.Equal(1, recorder.LookupCount);
+        Assert.DoesNotContain("saved-test-secret", JsonSerializer.Serialize(((OkObjectResult)response).Value));
+    }
+
+    [Fact]
+    public async Task ExplicitPasswordOverridesSavedWithoutLookup()
+    {
+        var (controller, recorder) = CreateController();
+        var response = await controller.TestSmtp(Request() with { Password = "typed-test-secret" }, CancellationToken.None);
+
+        Assert.True(Succeeded(response));
+        Assert.Equal("typed-test-secret", recorder.SentCommand?.Password);
+        Assert.Equal(0, recorder.LookupCount);
+    }
+
+    [Theory]
+    [InlineData("host")]
+    [InlineData("port")]
+    [InlineData("username")]
+    [InlineData("ssl")]
+    public async Task ChangedConnectionRequiresExplicitPassword(string field)
+    {
+        var (controller, recorder) = CreateController();
+        var request = field switch
+        {
+            "host" => Request() with { Host = "other.example.invalid" },
+            "port" => Request() with { Port = 2525 },
+            "username" => Request() with { Username = "other-user" },
+            _ => Request() with { UseSsl = false }
+        };
+
+        var response = await controller.TestSmtp(request, CancellationToken.None);
+
+        Assert.False(Succeeded(response));
+        Assert.Null(recorder.SentCommand);
+    }
+
+    [Fact]
+    public async Task UnknownChannelDoesNotSend()
+    {
+        var (controller, recorder) = CreateController();
+        recorder.Channel = null;
+
+        var response = await controller.TestSmtp(Request(), CancellationToken.None);
+
+        Assert.False(Succeeded(response));
+        Assert.Null(recorder.SentCommand);
+    }
+
+    [Fact]
+    public async Task NewChannelKeepsAdHocTestBehavior()
+    {
+        var (controller, recorder) = CreateController();
+
+        var response = await controller.TestSmtp(Request() with { ChannelId = null }, CancellationToken.None);
+
+        Assert.True(Succeeded(response));
+        Assert.Equal(string.Empty, recorder.SentCommand?.Password);
+        Assert.Equal(0, recorder.LookupCount);
+    }
+
+    private static (AdminChannelsController Controller, RecordingAdminSmtpMediator Recorder) CreateController()
+    {
+        var mediator = DispatchProxy.Create<IMediator, RecordingAdminSmtpMediator>();
+        var recorder = (RecordingAdminSmtpMediator)mediator;
+        recorder.Channel = new EmailChannel
+        {
+            Id = ChannelId,
+            ServiceName = "TestService",
+            EmailChannelType = EmailChannelType.Smtp,
+            Settings = new SmtpChannelSettings
+            {
+                Host = "smtp.example.invalid", Port = 587,
+                Username = "test-user", Password = "saved-test-secret", UseSsl = true
+            }
+        };
+        return (new AdminChannelsController(mediator), recorder);
+    }
+
+    private static TestSmtpRequest Request() => new(
+        "smtp.example.invalid", 587, "test-user", "", true,
+        "changed@example.invalid", "Changed sender", "recipient@example.invalid", ChannelId);
+
+    private static bool Succeeded(IActionResult response)
+    {
+        var body = JsonSerializer.Serialize(((OkObjectResult)response).Value);
+        return JsonDocument.Parse(body).RootElement.GetProperty("success").GetBoolean();
+    }
+}