(val[, msg])</h3>

<p>Asserts that the given <em>val</em> is <em>null</em>.</p>

<pre><code>assert.isNull(null);
</code></pre>

<h3 id="assert-isNotNull-val-msg-">assert.isNotNull(val[, msg])</h3>

<p>Asserts that the given <em>val</em> is not <em>null</em>.</p>

<pre><code>assert.isNotNull(undefined);
assert.isNotNull(false);
</code></pre>

<h3 id="assert-isUndefined-val-msg-">assert.isUndefined(val[, msg])</h3>

<p>Asserts that the given <em>val</em> is <em>undefined</em>.</p>

<pre><code>assert.isUndefin