https://github.com/rillig/gobco

Measure branch coverage of golang tests
https://github.com/rillig/gobco

coverage coverage-testing go golang

Last synced: 19 days ago
JSON representation

Measure branch coverage of golang tests

• Host: GitHub
• URL: https://github.com/rillig/gobco
• Owner: rillig
• Created: 2018-11-22T06:46:06.000Z (over 5 years ago)
• Default Branch: master
• Last Pushed: 2024-05-07T17:16:41.000Z (about 2 months ago)
• Last Synced: 2024-05-07T18:48:46.937Z (about 2 months ago)
• Topics: coverage, coverage-testing, go, golang
• Language: Go
• Homepage:
• Size: 563 KB
• Stars: 60
• Watchers: 3
• Forks: 12
• Open Issues: 5
• Metadata Files:
  • Readme: README.md

Lists

• awesome-code-coverage - gobco

README

        
[![Build Status](https://app.travis-ci.com/rillig/gobco.svg?branch=master)](https://app.travis-ci.com/github/rillig/gobco)

[![codecov](https://codecov.io/gh/rillig/gobco/branch/master/graph/badge.svg)](https://codecov.io/gh/rillig/gobco)

# GOBCO - Golang Branch Coverage

Gobco measures condition coverage of Go code.

Gobco is intended to be used in addition to `go test -cover`.

For example, gobco does not detect functions or methods that are completely

unused, it only notices them if they contain any conditions or branches.

Gobco also doesn't cover `select` statements.

## Installation

With go1.17 or later:

```text

$ go install github.com/rillig/gobco@latest

```

With go1.16:

```text

$ go get github.com/rillig/gobco

```

Older go releases are not supported.

## Usage

To run gobco on a single package, run it in the package directory:

~~~text

$ gobco

~~~

The output typically looks like the following example, taken from package

[github.com/rillig/pkglint](https://github.com/rillig/pkglint):

```text

ok  	github.com/rillig/pkglint/v23	29.648s

Condition coverage: 8720/8840

...

changes.go:171:61: condition "n == 6" was 12 times true but never false

distinfo.go:268:8: condition "alg == \"SHA1\"" was 16 times false but never true

distinfo.go:322:13: condition "remainingHashes[0].algorithm == alg" was 8 times true but never false

...

mkcondsimplifier.go:141:31: condition "p[2] == p[1]-'A'+'a'" was 26 times true but never false

...

vartypecheck.go:1027:11: condition "len(invalid) > 1" was once false but never true

vartypecheck.go:1628:42: condition "cv.MkLines.pkg != nil" was 8 times true but never false

vartypecheck.go:1630:6: condition "distname.IsConstant()" was 8 times true but never false

```

## Adding custom test conditions

If you want to ensure that the tests cover a certain condition in your code,

you can insert the desired condition into the code

and assign it to the underscore:

~~~go

func square(x int) int {

    _ = x > 50

    _ = x == 0

    _ = x < 0

    return x * x

}

~~~

The compiler will see that these conditions are side-effect-free and will thus

optimize them away, so there is no runtime overhead.

Since the above conditions are syntactically recognizable as boolean

expressions, gobco inserts its coverage code around them.

Note that for boolean expressions that don't clearly look like boolean

expressions, you have to write `cond == true` instead of a simple `cond` since

as of March 2021, gobco only analyzes the code at the syntactical level,

without resolving any types.