How to have Go coverage HTML with light background?

Question

Consider the following command:

go tool cover -html=coverage.out

Is there a way to make the resulting HTML dark on light (rather than the default light characters on dark background)?

I did not find anything about this neither in the documentation nor in the help pages referenced therein (go tool cover --help and go help testflag)

Keffiyeh

@downvoter: It would be really nice if you could explain what is wrong with the question. I think the need is genuine and I also did a reasonable effort to find the answer myself before asking here. – Keffiyeh

Also, do I understand correctly that asking about any Golang tool (e.g. go fmt, go imports, etc...) is not OK here, because it is not strictly related to programming? – Keffiyeh

If you have some programing related question about go vet you can ask here. But how to change the color of a GUI tool is totally not related to programming. IMHO such stuff does not belong on an stackexchange forum. You should ask on reddit or golang-nuts. – Padang

@Volker: if your question generally covers...software tools commonly used by programmers; and is a practical, answerable problem that is unique to software development...then you’re in the right place to ask your question! I would say that description fits this question: it is about a practical, answerable problem with a development-specific tool. Questions about Git, IDEs, and other developer tools have long been accepted on SO. – Guido

@Guido I think the question is not practical and not answerable (except "you cannot"). This seems about taste. – Padang

@Volker: for me "you cannot" is also an answer (I generally write it explicitly in my questions, this time I forgot). Because if I know that "you cannot", I know that I did not miss anything and do not keep looking. – Keffiyeh

Also, before asking the question, how would I know in advance that the answer is "you cannot"? – Keffiyeh

Answer 1

Not with the built-in tool. There's nothing preventing you from piping the output through some script to change CSS colors, though, or to reference an external CSS file that sets the colors you prefer.

Predominant

Answer 2

As mentioned by @Flimzy, this is not supported with the built-in tool.

Though, looking at the coverage.html file output by the cover tool.

You can do something like this:

go tool cover -o coverage.html -html=coverage.out; sed -i 's/black/whitesmoke/g' coverage.html; sensible-browser coverage.html

which will write the output to coverage.html using the -o flag and then use sed to change occurrences of black to whitesmoke. It will then use your default browser to open the file.

Note #1: Obviously, this will not work once the tool is updated not to output black color background. Though, if this changes, there is probably a lot better support for different color schemes.

Note #2: If you use heat maps -covermode=count, the light green might look awkward on the smokewhite color. Feel free to try different color accents though.

Huberty