public async Task ProcessAsync_ItemAlreadyHasTitleThrowsInvalidOperationException()
{
// Arrange
var panelContext = new PanelContext();
panelContext.TrySetTitle(content: new HtmlString("Existing title"));
var context = new TagHelperContext(
tagName: "govuk-panel-title",
allAttributes: new TagHelperAttributeList(),
items: new Dictionary <object, object>()
{
{ typeof(PanelContext), panelContext }
},
uniqueId: "test");
var output = new TagHelperOutput(
"govuk-panel-title",
attributes: new TagHelperAttributeList(),
getChildContentAsync: (useCachedResult, encoder) =>
{
var tagHelperContent = new DefaultTagHelperContent();
tagHelperContent.SetHtmlContent("Title");
return(Task.FromResult <TagHelperContent>(tagHelperContent));
});
var tagHelper = new PanelTitleTagHelper();
// Act & Assert
var ex = await Assert.ThrowsAsync <InvalidOperationException>(() => tagHelper.ProcessAsync(context, output));
Assert.Equal("Cannot render <govuk-panel-title> here.", ex.Message);
}
