public void ContainsKeyFailsWithNullCollection()
{
var e = Assert.Throws <ArgumentNullException>(() =>
NameValueCollectionExtensions.ContainsKey(null, null));
Assert.Equal("collection", e.ParamName);
}
public void WhenSourceIsNull_ThenThrowException()
{
Assert.Throws <ArgumentNullException>(() => NameValueCollectionExtensions.ContainsKey(null, "key1"));
}