Refactor Firebase E2E drift test helpers

Author: AdamEssenmacher

tests/E2E/Firebase.Foundation/FirebaseFoundationE2E/FirebaseRuntimeDriftCases.Helpers.cs

@@ -0,0 +1,89 @@
+using System.Reflection;
+using Foundation;
+using ObjCRuntime;
+
+namespace FirebaseFoundationE2E;
+
+static partial class FirebaseRuntimeDriftCases
+{
+    sealed class ObjCExceptionProbe : IDisposable
+    {
+        bool disposed;
+
+        ObjCExceptionProbe()
+        {
+            Runtime.MarshalObjectiveCException += OnMarshalObjectiveCException;
+        }
+
+        public static ObjCExceptionProbe Attach()
+        {
+            return new ObjCExceptionProbe();
+        }
+
+        public NSException? Exception { get; private set; }
+
+        public MarshalObjectiveCExceptionMode? ExceptionMode { get; private set; }
+
+        public bool HasException => Exception is not null;
+
+        public string Name => FormatDetail(Exception?.Name?.ToString());
+
+        public string Reason => FormatDetail(Exception?.Reason);
+
+        public string Mode => FormatDetail(ExceptionMode?.ToString());
+
+        public void Dispose()
+        {
+            if (disposed)
+            {
+                return;
+            }
+
+            Runtime.MarshalObjectiveCException -= OnMarshalObjectiveCException;
+            disposed = true;
+        }
+
+        void OnMarshalObjectiveCException(object? sender, MarshalObjectiveCExceptionEventArgs args)
+        {
+            Exception ??= args.Exception;
+            ExceptionMode ??= args.ExceptionMode;
+        }
+    }
+
+    static string FormatNSError(NSError error)
+    {
+        return $"{error.Domain} ({error.Code}): {error.LocalizedDescription}";
+    }
+
+    static void RequireConstructor(Type type, Type[] parameterTypes, string selector)
+    {
+        var constructor = type.GetConstructor(parameterTypes);
+        if (constructor is null)
+        {
+            throw new InvalidOperationException(
+                $"Expected managed constructor '{type.FullName}({string.Join(", ", parameterTypes.Select(parameterType => parameterType.FullName))})' " +
+                $"was not found for selector '{selector}'.");
+        }
+    }
+
+    static void RequireVoidMethod(Type type, string methodName, string selector)
+    {
+        RequireVoidMethod(type, methodName, Type.EmptyTypes, selector);
+    }
+
+    static void RequireVoidMethod(Type type, string methodName, Type[] parameterTypes, string selector)
+    {
+        var method = type.GetMethod(methodName, BindingFlags.Instance | BindingFlags.Public, binder: null, types: parameterTypes, modifiers: null);
+        if (method?.ReturnType != typeof(void))
+        {
+            throw new InvalidOperationException(
+                $"Expected managed API '{type.FullName}.{methodName}({string.Join(", ", parameterTypes.Select(parameterType => parameterType.FullName))})' " +
+                $"to return void for selector '{selector}', observed '{method?.ReturnType.FullName ?? "<missing>"}'.");
+        }
+    }
+
+    static string FormatDetail(string? value)
+    {
+        return string.IsNullOrWhiteSpace(value) ? "<empty>" : value;
+    }
+}