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    <p><strong>There's a useful LINQ operator called <a href="http://msdn.microsoft.com/en-us/library/bb495305.aspx" rel="nofollow"><code>SequenceEqual()</code></a> which compares two sequences for equality.</strong> <code>SequenceEqual()</code> walks through any two <code>IEnumerable&lt;&gt;</code> sequences and verifies that they have the same number of elements and that elements at the same index are equal (using the default equality comparer). However, since you have nested collections, you need to extend the concept of equality to apply to them as well. Fortunately, there's an overload that allows you supply your own <code>IEqualityComparer&lt;&gt;</code> object. </p> <p>Since it's awkward to constantly have to define a class to provide equality semantics, I've written a generic extension that allows you to use a delegate instead. Let's look at the code:</p> <pre><code>public static class ComparerExt { private class GenericComparer&lt;T&gt; : IEqualityComparer&lt;T&gt; { private readonly Func&lt;T, T, bool&gt; m_EqualityFunc; public GenericComparer( Func&lt;T,T,bool&gt; compareFunc ) { m_EqualityFunc = compareFunc; } public bool Equals(T x, T y) { return m_EqualityFunc(x, y); } } // converts a delegate into an IComparer public static IEqualityComparer&lt;T&gt; AreEqual&lt;T&gt;( Func&lt;T,T,bool&gt; compareFunc ) { compareFunc.ThrowIfNull("compareFunc"); return new GenericComparer&lt;T&gt;(compareFunc); } } </code></pre> <p><strong>Now, we can compare two sequences easily enough:</strong></p> <pre><code>Assert.IsTrue( // check that outer sequences are equivalent... a1.SequenceEqual( a2, // define equality as inner sequences being equal... ComparerExt.AreEqual( (a,b) =&gt; a.SequenceEqual(b) ) ); </code></pre>
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    1. POrecursive assert on collection
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    1. COThis seems to solve the problem, but it still works only for 1-level nested collections, so not really a generic solution :) And in my real case I have KeyValuePair<string,string[]>[] and your way in solving the issue seems too complicated
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    2. CO@wysek: So when you say you're looking for a *generic solution*, do you mean for any level of nesting? That wasn't clear in you question. Let us know if that's the case.
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    3. COI have rather been looking for a tool already existing... But seems there is none. I have implemented my own non-generic comparer for this, however thanks for the effort!
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