WireMock.Net/test/WireMock.Net.Tests/TestUtils.cs

using System;
using System.Reflection;

namespace WireMock.Net.Tests;

public static class TestUtils
{
    public static T GetPrivateFieldValue<T>(this object obj, string fieldName)
    {
        var field = obj.GetType().GetTypeInfo().GetField(fieldName, BindingFlags.NonPublic | BindingFlags.Instance);

        return (T)field.GetValue(obj);
    }

    /// <summary>
    /// Set a _private_ Field Value on a given Object
    /// </summary>
    /// <typeparam name="T">Type of the Property</typeparam>
    /// <param name="obj">Object from where the Property Value is returned</param>
    /// <param name="propertyName">Property name as string.</param>
    /// <param name="value">the value to set</param>
    public static void SetPrivateFieldValue<T>(this object obj, string propertyName, T value)
    {
        if (obj == null)
        {
            throw new ArgumentNullException(nameof(obj));
        }

        Type t = obj.GetType();
        FieldInfo fi = null;
        while (fi == null && t != null)
        {
            fi = t.GetField(propertyName, BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance);
            t = t.BaseType;
        }

        if (fi == null)
        {
            throw new ArgumentOutOfRangeException(nameof(propertyName), $"Field {propertyName} was not found in Type {obj.GetType().FullName}");
        }

        fi.SetValue(obj, value);
    }

    /// <summary>
    /// Sets a _private_ Property Value from a given Object.
    /// </summary>
    /// <typeparam name="T">Type of the Property</typeparam>
    /// <param name="obj">Object from where the Property Value is set</param>
    /// <param name="propertyName">Property name as string.</param>
    /// <param name="value">Value to set.</param>
    public static void SetPrivatePropertyValue<T>(this object obj, string propertyName, T value)
    {
        Type? t = obj.GetType();
        PropertyInfo? propertyInfo = null;
        while (propertyInfo == null && t != null)
        {
            propertyInfo = t.GetProperty(propertyName, BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance);
            t = t.BaseType;
        }

        if (propertyInfo == null)
        {
            throw new ArgumentOutOfRangeException(nameof(propertyName), $"Private property {propertyName} was not found in Type {obj.GetType().FullName}");
        }

        propertyInfo.SetValue(obj, value);
    }
}