dcover is a very shameless copycat of golang's cover tool (in terms of its HTML output option).
Given a directory of D coverage files (.lst), this tool will create a HTML file that visually shows which lines have been covered, and which have not.
An example can be found here
dub test -b unittest-cov; dub run dcover -- .This should generate an index.html file, which is very similar to the output of golang's cover tool.