Go cover tool for maximum productivity.

It is similar to go tool cover -html=cover.out but not leaving the terminal. It was inspired by gocovsh but I wanted it to work a bit different.

The aim is to help me in writing tests spending as little attention and key presses as possible.


Key features

  • You dont leave the terminal.
  • It’s non-interactive like ls, cd and most of cli commands. Life is too short to navigate menus.
  • It’s precise, it only output the code you asked.

How to use

Go to the project dir, it requires to be inside the project to work (go.mod needed).

Create coverage profile as usual: go test -coverprofile cover.out ./....

Render it cover (cover.out is the default profile name). By default it renders all files in the current directory recursive (./...).

But the best part is filters. You determine what coverage target you want, you may have simple rule (all files at least 80% covered) or as much flexible as you want (separate coverage target for each file, package or function, exclude experimental subpackages or unexported functions).

Then you may write your tests with very little distraction: no typing, no clicking, no switching to browser and back, very little of scrolling.

You may also use it as an automated checker as it can return exit code 1 if something is selected. You set the rules and eliminate what breaks them.

cover --exit-code <target_filters...> && echo "You are covered!" || echo "There is something to cover"


Select by path. Paths are relative to the current directory.

. # not recursive

Select by package name, type name, function name or combined


File filter is a glob, function filter is a regexp.



Filter by coverage.

tlog.go:b70  # filter by file name, then by coverage: *b* for below, 70 is percent
             # Select all functions in a file with coverage below 70%

# there are 'b' (below) or 'l' (less then) and 'a' (above) or 'g' (greater then) filters

Logger:b80:a10  # all methods of Logger with coverage from 10% to 80%
:b80            # every function in the current directory covered below 80% recursive

# function coverage is compared by default, but if `...` wildcard path filter suffix is used then file total coverage is compared.

wire:l80     # functions with less than 80% coverage
ext/...:l80  # files with less than 80% total coverage

Negative filter. Filter prefixed with ! unselects previously selected functions.



Filter chaining.

# quotes to prevent shell substitution

./ext/... '!tlgraylog'                 # extensions except tlgraylog
./wire/ '!Encoder' '!Decoder' '!:a80'  # functions in wire package except Encoder and Decoder methods and except well covered
...:b80                                # files to cover

Examples are from tlog.


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