Fix NullReferenceException comparing markup with style attributes#110
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Fix NullReferenceException comparing markup with style attributes BunitMarkupComparer parsed markup with a CSS-unaware HtmlParser, so an element's inline style parsed to a null ICssStyleDeclaration. AngleSharp .Diffing's StyleAttributeComparer compares style attributes semantically, so it dereferenced that null and threw the moment two style attributes differed — surfacing as an NRE instead of a diff on any HTML snapshot whose elements carry differing styles. Parse through a CSS-enabled configuration (Configuration.Default.WithCss()) so every element gets a real CSS object model and the style comparison works. AngleSharp.Css is already present transitively via bunit. Add a regression test covering two markup strings that differ only in style-attribute whitespace, which forces the comparer through the CSS parse that previously crashed.
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Fix NullReferenceException comparing markup with style attributes
BunitMarkupComparer parsed markup with a CSS-unaware HtmlParser, so an element's inline style parsed to a null ICssStyleDeclaration. AngleSharp .Diffing's StyleAttributeComparer compares style attributes semantically, so it dereferenced that null and threw the moment two style attributes differed — surfacing as an NRE instead of a diff on any HTML snapshot whose elements carry differing styles.
Parse through a CSS-enabled configuration (Configuration.Default.WithCss()) so every element gets a real CSS object model and the style comparison works. AngleSharp.Css is already present transitively via bunit.
Add a regression test covering two markup strings that differ only in style-attribute whitespace, which forces the comparer through the CSS parse that previously crashed.