covdata

Overview ¶

Covdata is a program for manipulating and generating reports from 2nd-generation coverage testing output files, those produced from running applications or integration tests. E.g.

$ mkdir ./profiledir
$ go build -cover -o myapp.exe .
$ GOCOVERDIR=./profiledir ./myapp.exe <arguments>
$ ls ./profiledir
covcounters.cce1b350af34b6d0fb59cc1725f0ee27.821598.1663006712821344241
covmeta.cce1b350af34b6d0fb59cc1725f0ee27
$

Run covdata via "go tool covdata <mode>", where 'mode' is a subcommand selecting a specific reporting, merging, or data manipulation operation. Descriptions on the various modes (run "go tool cover <mode> -help" for specifics on usage of a given mode:

1. Report percent of statements covered in each profiled package

$ go tool covdata percent -i=profiledir
cov-example/p	coverage: 41.1% of statements
main	coverage: 87.5% of statements
$

2. Report import paths of packages profiled

$ go tool covdata pkglist -i=profiledir
cov-example/p
main
$

3. Report percent statements covered by function:

$ go tool covdata func -i=profiledir
cov-example/p/p.go:12:		emptyFn			0.0%
cov-example/p/p.go:32:		Small			100.0%
cov-example/p/p.go:47:		Medium			90.9%
...
$

4. Convert coverage data to legacy textual format:

$ go tool covdata textfmt -i=profiledir -o=cov.txt
$ head cov.txt
mode: set
cov-example/p/p.go:12.22,13.2 0 0
cov-example/p/p.go:15.31,16.2 1 0
cov-example/p/p.go:16.3,18.3 0 0
cov-example/p/p.go:19.3,21.3 0 0
...
$ go tool cover -html=cov.txt
$

5. Merge profiles together:

$ go tool covdata merge -i=indir1,indir2 -o=outdir -modpaths=github.com/go-delve/delve
$

6. Subtract one profile from another

$ go tool covdata subtract -i=indir1,indir2 -o=outdir
$

7. Intersect profiles

$ go tool covdata intersect -i=indir1,indir2 -o=outdir
$

8. Dump a profile for debugging purposes.

$ go tool covdata debugdump -i=indir
<human readable output>
$