How to mock umbraco content and its properties so I could get the correct value of the property and HasProperty bool value?

I'm trying to test such method:

        var properties = [...] // properties collection
        UmbProperties(properties, content, model);

The method content:

    protected T UmbProperties(PropertyInfo[] properties, IPublishedContent content, T model)
    {
        foreach (PropertyInfo property in properties)
        {
            string umbracoPropertyName = Char.ToLowerInvariant(property.Name[0]) + property.Name.Substring(1);
            bool umbracoHasProperty = content.HasProperty(umbracoPropertyName); // this returns System.NullReferenceException when testing

            [...]
        }

        return model;
    }

Currently in my test method I have:

    public void For_GetPropertyValueOfType()
    {
        var contentStub = new Mock<IPublishedContent>();
        var propertyStub = new Mock<IPublishedProperty>();

        propertyStub.Setup(p => p.Value).Returns("property value");

        contentStub.Setup(c => c.GetProperty("test", false)).Returns(propertyStub.Object);

        var model = [...] // some model
        var content = contentStub.Object;

        var properties = [...] // properties collection
        obj.UmbProperties(properties, content, model);

        [...]
    }

content is set well and not null, but HasProperty returns an error:

System.NullReferenceException: 'Object reference not set to an instance of an object.'

How to get HasProperty working correctly when setting property in the test method?

I don't want to do this for example:

var propertyValue = content.GetPropertyValue<string>("test");
var hasProp = propertyValue != null;

because I'm checking for the property type later in UmbProperties.

And this doesn't work either:

        var propertyValue = content.GetPropertyValue("test");
        var hasProp1 = propertyValue != null; // this returns false as propertyValue comes null if I;m not using type conversion as above