 prefix is deprecated beginning with NUnit 2.5.1
   and will be removed in NUnit 3.0.

<h3>SubstringConstraint</h3>

<h4>Action</h4>
<p>Tests for a substring.

<h4>Constructor</h4>
<div class="code"><pre class="prettyprint">
SubstringConstraint(string expected)
</pre></div>

<h4>Syntax</h4>
<div class="code"><pre class="prettyprint">
Is.StringContaining(string expected)
ContainsSubstring(string expected)
Contains(string expected)
[Obsolete] Text.Contains(string expected)
[Obsolete] Text.DoesNotContain(strin