Is there evidence to support the Dunning-Kruger effect?
Yes, there are research showing a relationship between skills and not only "sit down tests". A systematic review by Madmood (2016) found "self-reported and demonstrated information literacy skills" supported the Dunning-Kruger phenomena. Demonstrated information literacy was from derived sources such as "observations, field notes, participant reflexive journals, expert grading of searching tasks, analysis of students’ theses, quizzes, and information related assignments".

References: 

Mahmood, K. (2016). Do People Overestimate Their Information Literacy Skills? A Systematic Review of Empirical Evidence on the Dunning-Kruger Effect. Communications in Information Literacy, 10 (2), 199-213. https://doi.org/10.15760/comminfolit.2016.10.2.24