Golang testing

Go ships with a test suite.

Documentation

testing

https://pkg.go.dev/testing@go1.18.3

Usage

go test -run      # run all tests
go test -run Foo  # run top-level tests containing 'Foo'

Example

The builtin go test framework is fairly minimalist.
Tests are just functions, you can loop them if useful.

Tests are typically kept alongside code.

// myproject/mypackage/mylib.go

package mypackage

func Hello(name string) string {
    return "Hello, " + name
}

// myproject/mypackage/mylib_test.go

package mypackage

import "testing"

func TestHello(t *testing.T) {
    res := Hello("Adam")
    if res != "Hello, Adam" {
        t.Errorf("Hello() result did not match")
    }
}

Assertions

There are no assertions, you are responsible for tests and messages.

func TestHello(t *testing.T) {
    // log message and fail (but continue executing)
    t.Errorf("An expectation was not satisfied")
    t.Fail()         // mark test as failed, but continue
    t.FailNow()      // mark test as failed and stop executing

    t.Skip("Reason") // log, and stop executing

    t.TempDir()      // provides a tempdir that is deleted once test finishes running
}

Subtests

Evaluate subtests under one function using t.Run("TESTNAME", ...).

func TestHello(t *testing.T) {
    cases := []struct {                          // <-- slice of structs containing testdata
        test       string
        name       string
        expects    string
    }{ { test: "ValidName", name: "Adam", },
       { test: "NilName", name: nil, } }

    for _, case := range cases {
        t.Run(case.test, func(t, *testing.T) {   // <-- t.Run() evaluates each case
            res := Hello(case.name)
            if res != case.expects {
                t.Errorf("Failed because...")
            }
        }
    }
}

You can also implement setup/teardown this way using defer functions.

Benchmarking

There are tools for benchmarking. See docs

Fuzzing

There are tools for fuzzing tests. See docs