public void TestSymbolsArgument() { Assert.ThrowsAsync <ArgumentException>(async() => await YahooHistory.GetPricesAsync("")); Assert.ThrowsAsync <ArgumentException>(async() => await YahooHistory.GetPricesAsync(new string[] { })); Assert.ThrowsAsync <ArgumentException>(async() => await YahooHistory.GetPricesAsync(new string[] { "" })); Assert.ThrowsAsync <ArgumentException>(async() => await YahooHistory.GetPricesAsync(new string[] { "C", "" })); }