$this->assertSession()->titleEquals() is not working in a FunctionalJavascript test.
The problem seems to be that $title_element->getText() returns an empty string, getHtml() however seems to be working.
Also, the error message is not helpful at all, as it doesn't show what it is actually comparing, you have to debug it to find that out:
Behat\Mink\Exception\ExpectationException: Title found
Not sure, might be a bug in Selection2Driver? We could work around it with driver specific code I guess..
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