Span in Product Title

Hello all,

I made a span in the Product Title in WooCommerce

Product Title:
<span class=“testclass”>Test</span> My Product

This is in the CSS of the theme:
span.testclass {
background: #FDAB9F;
color: #fff;
font-size: 85%;
letter-spacing: 0.06em;
text-transform: uppercase;
padding: 2px 4px 1px 4px;
margin: 0 3px 5px 0;
}

This span works for post titles but not for product titles in WooCommerce.
Anybody knows how to solve this problem.

Thank you!