github.com/stretchr/testify v1.8.4: assert.Eventually, assert.Never

Clean-room public code sample — generation instructions

Write a brand-new, minimal, self-contained code sample in this clean-room directory.
Do not copy, paraphrase, or reference any existing project source. Work only from this spec.

A csx.json manifest scaffold already exists. Do not recreate it from memory. Preserve its case.goal, packages and symbols; fill its empty case.contract with exact assertions and correct its environment, commands and verifierAdapter for the files you generate.

Goal: verify pkg:golang/github.com/stretchr/testify@v1.8.4
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/github.com/stretchr/testify@v1.8.4
Demonstrate these symbols/APIs:
  - assert.Eventually
  - assert.Never

Rules:
  - One focused purpose; the smallest project that proves the goal.
  - Include a contract test (test/contract.*) that runs OFFLINE and exits 0 exactly when the goal behavior works.
  - Pin every dependency with a lockfile so resolution is reproducible.
  - No secrets, credentials, or tokens. No real URLs (only example.com or localhost). No absolute paths.
  - No personal names, emails, company names, or project identifiers of any kind.
  - No binaries and no generated output (node_modules, dist, target, venv, .git, .env).
  - Keep it under 200 files and 256KB packed.

{"case":{"caseId":"case:sha256:14bbf2f96ae1788c9275b9696a5d28e1dd6acacccd82da263ad8220c4bd45c5d","contract":["assert.Eventually polls condition periodically and returns true when condition becomes true within waitFor timeout","assert.Eventually records failure and returns false when condition is not satisfied within waitFor timeout","assert.Never polls condition periodically and returns true when condition remains false throughout waitFor duration","assert.Never records failure and returns false when condition becomes true during waitFor duration","assert.EventuallyWithT collects assertion results via CollectT and passes when all assertions succeed within waitFor timeout"],"goal":"verify pkg:golang/github.com/stretchr/testify@v1.8.4","kind":"HOW","packages":["pkg:golang/github.com/stretchr/testify@v1.8.4"],"schemaVersion":1,"symbols":["assert.Eventually","assert.Never"]},"contractCommand":["go","run","./test"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"golang","libc":"glibc","libcVersion":"2.39","os":"linux","osVersionBucket":"24","packageManager":"go","schemaVersion":1},"license":"MIT-0","packages":["pkg:golang/github.com/stretchr/testify@v1.8.4"],"schemaVersion":1,"subject":"pkg:golang/github.com/stretchr/testify@v1.8.4","symbols":["assert.Eventually","assert.Never"],"verifierAdapter":"golang@1"}

module example.com/sample

go 1.20

require github.com/stretchr/testify v1.8.4

require (
	github.com/davecgh/go-spew v1.1.1 // indirect
	github.com/pmezard/go-difflib v1.0.0 // indirect
	gopkg.in/yaml.v3 v3.0.1 // indirect
)

github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
github.com/stretchr/testify v1.8.4 h1:CcVxjf3Q8PM0mHUKJCdn+eZZtm5yQwehR5yeSVQQcUk=
github.com/stretchr/testify v1.8.4/go.mod h1:sz/lmYIOXD/1dqDmKjjqLyZ2RngseejIcXlSw2iwfAo=
gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

package main

import (
	"fmt"
	"sync"
	"time"

	"github.com/stretchr/testify/assert"
)

type simpleTestingT struct {
	failed bool
}

func (t *simpleTestingT) Errorf(format string, args ...interface{}) {
	t.failed = true
	fmt.Printf("FAIL: "+format+"\n", args...)
}

func main() {
	t := &simpleTestingT{}

	// Scenario 1: State becomes ready asynchronously
	var (
		mu    sync.Mutex
		state = "initializing"
	)

	go func() {
		time.Sleep(20 * time.Millisecond)
		mu.Lock()
		state = "ready"
		mu.Unlock()
	}()

	// assert.Eventually polls until condition returns true
	ok := assert.Eventually(t, func() bool {
		mu.Lock()
		defer mu.Unlock()
		return state == "ready"
	}, 200*time.Millisecond, 10*time.Millisecond, "expected state to reach 'ready'")

	if ok && !t.failed {
		fmt.Println("assert.Eventually: state successfully reached 'ready'")
	}

	// Scenario 2: Stable invariant remains false
	var (
		errorCount int
	)

	// assert.Never verifies condition never becomes true during the observation window
	neverOk := assert.Never(t, func() bool {
		mu.Lock()
		defer mu.Unlock()
		return errorCount > 0
	}, 50*time.Millisecond, 10*time.Millisecond, "expected errorCount to remain zero")

	if neverOk && !t.failed {
		fmt.Println("assert.Never: errorCount safely remained zero")
	}

	// Scenario 3: EventuallyWithT for complex assertions inside the polling loop
	type WorkerResult struct {
		Processed int
		Status    string
	}
	res := &WorkerResult{Processed: 0, Status: "running"}

	go func() {
		time.Sleep(20 * time.Millisecond)
		mu.Lock()
		res.Processed = 10
		res.Status = "completed"
		mu.Unlock()
	}()

	withTOk := assert.EventuallyWithT(t, func(c *assert.CollectT) {
		mu.Lock()
		defer mu.Unlock()
		assert.Equal(c, "completed", res.Status)
		assert.Equal(c, 10, res.Processed)
	}, 200*time.Millisecond, 10*time.Millisecond, "worker did not complete as expected")

	if withTOk && !t.failed {
		fmt.Println("assert.EventuallyWithT: worker result validated successfully")
	}
}

{
  "schemaVersion": 1,
  "goal": "verify pkg:golang/github.com/stretchr/testify@v1.8.4",
  "kind": "HOW",
  "packages": [
    "pkg:golang/github.com/stretchr/testify@v1.8.4"
  ],
  "symbols": [
    "assert.Eventually",
    "assert.Never"
  ]
}

package main

import (
	"fmt"
	"os"
	"sync"
	"time"

	"github.com/stretchr/testify/assert"
)

type dummyTestingT struct {
	errors []string
	failed bool
}

func (t *dummyTestingT) Errorf(format string, args ...interface{}) {
	t.errors = append(t.errors, fmt.Sprintf(format, args...))
	t.failed = true
}

func main() {
	// Assertion 1: assert.Eventually polls condition periodically and returns true when condition becomes true within waitFor timeout
	{
		t := &dummyTestingT{}
		var mu sync.Mutex
		flag := false

		go func() {
			time.Sleep(20 * time.Millisecond)
			mu.Lock()
			flag = true
			mu.Unlock()
		}()

		ok := assert.Eventually(t, func() bool {
			mu.Lock()
			defer mu.Unlock()
			return flag
		}, 200*time.Millisecond, 10*time.Millisecond)

		if !ok || t.failed || len(t.errors) != 0 {
			fmt.Fprintf(os.Stderr, "assertion 1 failed: Eventually did not return true for satisfied condition\n")
			os.Exit(1)
		}
	}

	// Assertion 2: assert.Eventually records failure and returns false when condition is not satisfied within waitFor timeout
	{
		t := &dummyTestingT{}
		ok := assert.Eventually(t, func() bool {
			return false
		}, 50*time.Millisecond, 10*time.Millisecond)

		if ok || !t.failed || len(t.errors) == 0 {
			fmt.Fprintf(os.Stderr, "assertion 2 failed: Eventually should return false and record error for unsatisfied condition\n")
			os.Exit(1)
		}
	}

	// Assertion 3: assert.Never polls condition periodically and returns true when condition remains false throughout waitFor duration
	{
		t := &dummyTestingT{}
		ok := assert.Never(t, func() bool {
			return false
		}, 50*time.Millisecond, 10*time.Millisecond)

		if !ok || t.failed || len(t.errors) != 0 {
			fmt.Fprintf(os.Stderr, "assertion 3 failed: Never should return true when condition remains false\n")
			os.Exit(1)
		}
	}

	// Assertion 4: assert.Never records failure and returns false when condition becomes true during waitFor duration
	{
		t := &dummyTestingT{}
		var mu sync.Mutex
		flag := false

		go func() {
			time.Sleep(20 * time.Millisecond)
			mu.Lock()
			flag = true
			mu.Unlock()
		}()

		ok := assert.Never(t, func() bool {
			mu.Lock()
			defer mu.Unlock()
			return flag
		}, 100*time.Millisecond, 10*time.Millisecond)

		if ok || !t.failed || len(t.errors) == 0 {
			fmt.Fprintf(os.Stderr, "assertion 4 failed: Never should return false and record error when condition becomes true\n")
			os.Exit(1)
		}
	}

	// Assertion 5: assert.EventuallyWithT collects assertion results via CollectT and passes when all assertions succeed within waitFor timeout
	{
		t := &dummyTestingT{}
		var mu sync.Mutex
		val := 0

		go func() {
			time.Sleep(20 * time.Millisecond)
			mu.Lock()
			val = 42
			mu.Unlock()
		}()

		ok := assert.EventuallyWithT(t, func(c *assert.CollectT) {
			mu.Lock()
			current := val
			mu.Unlock()
			assert.Equal(c, 42, current)
		}, 200*time.Millisecond, 10*time.Millisecond)

		if !ok || t.failed || len(t.errors) != 0 {
			fmt.Fprintf(os.Stderr, "assertion 5 failed: EventuallyWithT did not pass satisfied assertion\n")
			os.Exit(1)
		}
	}

	fmt.Println("All contract assertions passed.")
}