Read Enova credentials from configuration file

tests/SmartB2B.Enova.Tests/Program.cs

@@ -1,4 +1,5 @@
 using SmartB2B.Enova.Contracts;
+using SmartB2B.Enova.Service.Configuration;
 using SmartB2B.Enova.Service.Orders;
 using SmartB2B.Enova.Service.Rpc;
 using SmartB2B.Enova.Service.Runtime;
@@ -23,7 +24,8 @@ var tests = new (string Name, Func<Task> Run)[]
     ("Warstwa WAMP wysyła wynik jako kwargs", WampKeywordWireResult),
     ("Brak waluty zwraca stabilny błąd", MissingCurrency),
     ("Waluta inna niż PLN jest odrzucana", UnsupportedCurrency),
-    ("Brak katalogu Enovy jest wykrywany", MissingEnovaDirectory)
+    ("Brak katalogu Enovy jest wykrywany", MissingEnovaDirectory),
+    ("Sekrety są odczytywane z pliku konfiguracji", SecretsComeFromConfigurationFile)
 };
 
 var failures = 0;
@@ -179,6 +181,52 @@ static Task MissingEnovaDirectory()
     }
 }
 
+static Task SecretsComeFromConfigurationFile()
+{
+    var path = Path.Combine(Path.GetTempPath(), $"enova-settings-{Guid.NewGuid():N}.json");
+    try
+    {
+        File.WriteAllText(path, """
+            {
+              "portal": "demo",
+              "wamp": {
+                "serverUrl": "ws://localhost:8080/",
+                "reconnectDelaySeconds": 10
+              },
+              "enova": {
+                "installationPath": "C:/Enova",
+                "database": "Firma demo",
+                "operator": "Administrator",
+                "password": "haslo-z-pliku",
+                "documentDefinition": "ZO",
+                "saveMode": "Buffer"
+              },
+              "sql": {
+                "connectionString": "Server=db;Database=enova;User ID=user;Password=sql-z-pliku",
+                "commandTimeoutSeconds": 30
+              },
+              "diagnostics": {
+                "logDirectory": "C:/logs",
+                "logPrefix": "test"
+              }
+            }
+            """);
+
+        var runtime = ServiceSettings.Load(path).ResolveRuntimeSettings();
+
+        AssertEqual("haslo-z-pliku", runtime.EnovaConfiguration.Connection.Password, "hasło operatora");
+        AssertEqual(
+            "Server=db;Database=enova;User ID=user;Password=sql-z-pliku",
+            runtime.SqlConnectionString,
+            "connection string SQL");
+        return Task.CompletedTask;
+    }
+    finally
+    {
+        File.Delete(path);
+    }
+}
+
 static RpcInvocation CreateInvocation() => new(
     [],
     new Dictionary<string, object?>