Failing test PostTemplatesTestFunctions::test_insert_image_no_thumb

[benlk]

Sample error failed test: https://travis-ci.org/INN/Largo/jobs/204338888

Affecting all versions of Largo, after PR #1400 but, curiously, not #1400 itself.

This failing test is a known problem; it's not urgent, but it did need to be noted.

There was 1 failure:
1) PostTemplatesTestFunctions::test_insert_image_no_thumb
Failed asserting that two strings are equal.
--- Expected
+++ Actual
@@ @@
-'<h2>Headings</h2>
+'<p><img src="http://example.org/wp-content/uploads/2017/02/cat-771x510.jpg" alt="1559758083_cef4ef63d2_o" width="771" height="475" class="alignnone size-large wp-image-283" /></p>
+<h2>Headings</h2>
 <p>Integer posuere erat a ante venenatis dapibus posuere velit aliquet. Sed posuere consectetur est at lobortis. Nulla vitae elit libero, a pharetra augue. Fusce dapibus, tellus ac cursus commodo, tortor mauris condimentum nibh, ut fermentum massa justo sit amet risus. Donec sed odio dui.</p>'