internal/task/tweet_test.go - build - Git at Google

 // Copyright 2021 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.

 package task

 import (
 	"bytes"
 	"context"
 	"encoding/json"
 	"flag"
 	"fmt"
 	"image"
 	"image/png"
 	"io"
 	"net/http"
 	"net/http/httptest"
 	"os"
 	"path/filepath"
 	"reflect"
 	"strings"
 	"testing"

 	"github.com/google/go-cmp/cmp"
 	"golang.org/x/build/buildenv"
 	"golang.org/x/build/internal/secret"
 	"golang.org/x/build/internal/workflow"
 )

 var postTests = [...]struct {
 	name         string
 	kind         ReleaseKind
 	published    []Published
 	security     string
 	announcement string
 	randomSeed   int64
 	wantLog      string
 }{
 	{
 		name: "minor",
 		kind: KindMinor,
 		published: []Published{
 			{Version: "go1.17.1", Files: []WebsiteFile{{
 				OS: "linux", Arch: "arm64",
 				Filename: "go1.17.1.linux-arm64.tar.gz", Size: 102606384, Kind: "archive"}},
 			},
 			{Version: "go1.16.8"},
 		},
 		security:     "Includes security fixes for A and B.",
 		announcement: "https://groups.google.com/g/golang-announce/c/dx9d7IOseHw/m/KNH37k37AAAJ",
 		randomSeed:   234,
 		wantLog: `tweet text:
 🎊 Go 1.17.1 and 1.16.8 are released!

 🔐 Security: Includes security fixes for A and B.

 📢 Announcement: https://groups.google.com/g/golang-announce/c/dx9d7IOseHw/m/KNH37k37AAAJ

 ⬇️ Download: https://go.dev/dl/#go1.17.1

 #golang
 tweet image:
 $ go install golang.org/dl/go1.17.1@latest
 $ go1.17.1 download
 Downloaded   0.0% (        0 / 102606384 bytes) ...
 Downloaded  50.0% ( 51303192 / 102606384 bytes) ...
 Downloaded 100.0% (102606384 / 102606384 bytes)
 Unpacking go1.17.1.linux-arm64.tar.gz ...
 Success. You may now run 'go1.17.1'
 $ go1.17.1 version
 go version go1.17.1 linux/arm64` + "\n",
 	},
 	{
 		name: "minor-solo",
 		kind: KindMinor,
 		published: []Published{{Version: "go1.11.1", Files: []WebsiteFile{{
 			OS: "darwin", Arch: "amd64",
 			Filename: "go1.11.1.darwin-amd64.tar.gz", Size: 124181190, Kind: "archive"}},
 		}},
 		announcement: "https://groups.google.com/g/golang-announce/c/pFXKAfoVJqw",
 		randomSeed:   23,
 		wantLog: `tweet text:
 🎆 Go 1.11.1 is released!

 📣 Announcement: https://groups.google.com/g/golang-announce/c/pFXKAfoVJqw

 📦 Download: https://go.dev/dl/#go1.11.1

 #golang
 tweet image:
 $ go install golang.org/dl/go1.11.1@latest
 $ go1.11.1 download
 Downloaded   0.0% (        0 / 124181190 bytes) ...
 Downloaded  50.0% ( 62090595 / 124181190 bytes) ...
 Downloaded 100.0% (124181190 / 124181190 bytes)
 Unpacking go1.11.1.darwin-amd64.tar.gz ...
 Success. You may now run 'go1.11.1'
 $ go1.11.1 version
 go version go1.11.1 darwin/amd64` + "\n",
 	},
 	{
 		name: "beta",
 		kind: KindBeta,
 		published: []Published{{Version: "go1.17beta1", Files: []WebsiteFile{{
 			OS: "darwin", Arch: "amd64",
 			Filename: "go1.17beta1.darwin-amd64.tar.gz", Size: 135610703, Kind: "archive"}},
 		}},
 		announcement: "https://groups.google.com/g/golang-announce/c/i4EliPDV9Ok/m/MxA-nj53AAAJ",
 		randomSeed:   678,
 		wantLog: `tweet text:
 ⚡️ Go 1.17 Beta 1 is released!

 ⚙️ Try it! File bugs! https://go.dev/issue/new

 🗣 Announcement: https://groups.google.com/g/golang-announce/c/i4EliPDV9Ok/m/MxA-nj53AAAJ

 📦 Download: https://go.dev/dl/#go1.17beta1

 #golang
 tweet image:
 $ go install golang.org/dl/go1.17beta1@latest
 $ go1.17beta1 download
 Downloaded   0.0% (        0 / 135610703 bytes) ...
 Downloaded  50.0% ( 67805351 / 135610703 bytes) ...
 Downloaded 100.0% (135610703 / 135610703 bytes)
 Unpacking go1.17beta1.darwin-amd64.tar.gz ...
 Success. You may now run 'go1.17beta1'
 $ go1.17beta1 version
 go version go1.17beta1 darwin/amd64` + "\n",
 	},
 	{
 		name: "rc",
 		kind: KindRC,
 		published: []Published{{Version: "go1.17rc2", Files: []WebsiteFile{{
 			OS: "windows", Arch: "arm64",
 			Filename: "go1.17rc2.windows-arm64.zip", Size: 116660997, Kind: "archive"}},
 		}},
 		announcement: "https://groups.google.com/g/golang-announce/c/yk30ovJGXWY/m/p9uUnKbbBQAJ",
 		randomSeed:   456,
 		wantLog: `tweet text:
 🎉 Go 1.17 Release Candidate 2 is released!

 🏖 Run it in dev! Run it in prod! File bugs! https://go.dev/issue/new

 🔈 Announcement: https://groups.google.com/g/golang-announce/c/yk30ovJGXWY/m/p9uUnKbbBQAJ

 📦 Download: https://go.dev/dl/#go1.17rc2

 #golang
 tweet image:
 $ go install golang.org/dl/go1.17rc2@latest
 $ go1.17rc2 download
 Downloaded   0.0% (        0 / 116660997 bytes) ...
 Downloaded  50.0% ( 58330498 / 116660997 bytes) ...
 Downloaded 100.0% (116660997 / 116660997 bytes)
 Unpacking go1.17rc2.windows-arm64.zip ...
 Success. You may now run 'go1.17rc2'
 $ go1.17rc2 version
 go version go1.17rc2 windows/arm64` + "\n",
 	},
 	{
 		name: "major",
 		kind: KindMajor,
 		published: []Published{{Version: "go1.21.0", Files: []WebsiteFile{{
 			OS: "freebsd", Arch: "amd64",
 			Filename: "go1.21.0.freebsd-amd64.tar.gz", Size: 133579378, Kind: "archive"}},
 		}},
 		security:   "Includes a super duper security fix (CVE-123).",
 		randomSeed: 123,
 		wantLog: `tweet text:
 🥳 Go 1.21.0 is released!

 🔐 Security: Includes a super duper security fix (CVE-123).

 📝 Release notes: https://go.dev/doc/go1.21

 📦 Download: https://go.dev/dl/#go1.21.0

 #golang
 tweet image:
 $ go install golang.org/dl/go1.21.0@latest
 $ go1.21.0 download
 Downloaded   0.0% (        0 / 133579378 bytes) ...
 Downloaded  50.0% ( 66789689 / 133579378 bytes) ...
 Downloaded 100.0% (133579378 / 133579378 bytes)
 Unpacking go1.21.0.freebsd-amd64.tar.gz ...
 Success. You may now run 'go1.21.0'
 $ go1.21.0 version
 go version go1.21.0 freebsd/amd64` + "\n",
 	},
 }

 func TestTweetRelease(t *testing.T) {
 	for _, tc := range postTests {
 		t.Run(tc.name, func(t *testing.T) {
 			// Call the tweet task function in dry-run mode so it
 			// doesn't actually try to tweet, but capture its log.
 			var buf bytes.Buffer
 			ctx := &workflow.TaskContext{Context: context.Background(), Logger: fmtWriter{&buf}}
 			tweetURL, err := (SocialMediaTasks{RandomSeed: tc.randomSeed}).TweetRelease(ctx, tc.kind, tc.published, tc.security, tc.announcement)
 			if err != nil {
 				t.Fatal("got a non-nil error:", err)
 			}
 			if got, want := tweetURL, "(dry-run)"; got != want {
 				t.Errorf("unexpected tweetURL: got = %q, want %q", got, want)
 			}
 			if diff := cmp.Diff(tc.wantLog, buf.String()); diff != "" {
 				t.Errorf("log mismatch (-want +got):\n%s", diff)
 			}
 		})
 	}
 }

 type fmtWriter struct{ w io.Writer }

 func (f fmtWriter) Printf(format string, v ...interface{}) {
 	fmt.Fprintf(f.w, format, v...)
 }

 var mastodonAPI secret.MastodonCredentials
 var secretErr error
 var mastodonPMTarget = flag.String("mastodon", "", "Name of account to receive private message (e.g., @user@instance.suffix)")

 func init() {
 	secretErr = secret.InitFlagSupport(context.Background())
 	secret.JSONVarFlag(&mastodonAPI, "mastodon-api-secret", "Mastodon API secret to use for tests that post.")
 	flag.Set("mastodon-api-secret", fmt.Sprintf("secret:%s/%s", buildenv.Production.ProjectName, secret.NameMastodonAPISecret))
 }

 var updateFlag = flag.Bool("update", false, "Update golden files.")

 func TestDrawTerminal(t *testing.T) {
 	got, err := drawTerminal(`$ go install golang.org/dl/go1.18beta1@latest
 $ go1.18beta1 download
 Downloaded   0.0% (        0 / 111109966 bytes) ...
 Downloaded  50.0% ( 55554983 / 111109966 bytes) ...
 Downloaded 100.0% (111109966 / 111109966 bytes)
 Unpacking go1.18beta1.linux-s390x.tar.gz ...
 Success. You may now run 'go1.18beta1'
 $ go1.18beta1 version
 go version go1.18beta1 linux/s390x`)
 	if err != nil {
 		t.Fatalf("drawTerminal: got error=%v, want nil", err)
 	}
 	if *updateFlag {
 		encodePNG(t, filepath.Join("testdata", "terminal.png"), got)
 		return
 	}
 	want := decodePNG(t, filepath.Join("testdata", "terminal.png"))
 	if !got.Bounds().Eq(want.Bounds()) {
 		t.Fatalf("drawTerminal: got image bounds=%v, want %v", got.Bounds(), want.Bounds())
 	}
 	diff := func(a, b uint32) uint64 {
 		if a < b {
 			return uint64(b - a)
 		}
 		return uint64(a - b)
 	}
 	var total uint64
 	for y := 0; y < want.Bounds().Dy(); y++ {
 		for x := 0; x < want.Bounds().Dx(); x++ {
 			r0, g0, b0, a0 := got.At(x, y).RGBA()
 			r1, g1, b1, a1 := want.At(x, y).RGBA()
 			const D = 0xffff * 20 / 100 // Diff threshold of 20% for RGB color components.
 			if diff(r0, r1) > D || diff(g0, g1) > D || diff(b0, b1) > D || a0 != a1 {
 				t.Errorf("at (%d, %d):\n got RGBA %v\nwant RGBA %v", x, y, got.At(x, y), want.At(x, y))
 			}
 			total += diff(r0, r1) + diff(g0, g1) + diff(b0, b1)
 		}
 	}
 	if testing.Verbose() {
 		t.Logf("average pixel color diff: %v%%", 100*float64(total)/float64(0xffff*want.Bounds().Dx()*want.Bounds().Dy()))
 	}
 }

 func encodePNG(t *testing.T, name string, m image.Image) {
 	t.Helper()
 	var buf bytes.Buffer
 	err := (&png.Encoder{CompressionLevel: png.BestCompression}).Encode(&buf, m)
 	if err != nil {
 		t.Fatal(err)
 	}
 	err = os.WriteFile(name, buf.Bytes(), 0644)
 	if err != nil {
 		t.Fatal(err)
 	}
 }

 func decodePNG(t *testing.T, name string) image.Image {
 	t.Helper()
 	f, err := os.Open(name)
 	if err != nil {
 		t.Fatal(err)
 	}
 	defer f.Close()
 	m, err := png.Decode(f)
 	if err != nil {
 		t.Fatal(err)
 	}
 	return m
 }

 // TestPostToMastodonUsingCredentials always passes unless some invariant is badly wrong.
 // This is intended to allow as-close-to-real testing as possible.
 // It is capable of actual activity on Mastodon, this will be a DM
 // to a specified person, so don't get cute with your example recipient.
 // DO NOT AUTOMATE THIS TEST, IT SHOULD BE RUN BY A HUMAN.
 func TestPostToMastodonUsingCredentials(t *testing.T) {
 	pmTarget := strings.TrimSpace(*mastodonPMTarget)
 	t.Logf("private message target (-mastodon)=%v", pmTarget)
 	t.Logf("mastodonAPI=%v", mastodonAPI)
 	if pmTarget == "" {
 		t.Skipf("Nothing to do here without a '-mastodon' flag")
 	}
 	if secretErr != nil {
 		t.Skipf("Nothing to do here without access to secrets, err=%v", secretErr)
 	}
 	if mastodonAPI.Application == "" {
 		t.Skipf("Nothing to do here without a valid API key")
 	}

 	cl, err := NewTestMastodonClient(mastodonAPI, pmTarget)
 	if err != nil {
 		t.Fatalf("NewTestMastodonClient(%v, %s) error %v", mastodonAPI, pmTarget, err)
 	}

 	tc := &postTests[0]

 	var buf bytes.Buffer
 	ctx := &workflow.TaskContext{Context: context.Background(), Logger: fmtWriter{&buf}}
 	tweetURL, err := (SocialMediaTasks{RandomSeed: tc.randomSeed, MastodonClient: cl}).TrumpetRelease(ctx, tc.kind, tc.published, tc.security, tc.announcement)
 	t.Logf("Mastodon post URL=%v, err=%v", tweetURL, err)
 	t.Log(buf.String())
 }

 func TestPostTweet(t *testing.T) {
 	mux := http.NewServeMux()
 	mux.HandleFunc("upload.twitter.com/1.1/media/upload.json", func(w http.ResponseWriter, req *http.Request) {
 		if got, want := req.Method, http.MethodPost; got != want {
 			t.Errorf("/1.1/media/upload.json: got method %s, want %s", got, want)
 			return
 		}
 		if got, want := req.FormValue("media_category"), "tweet_image"; got != want {
 			t.Errorf("/1.1/media/upload.json: got media_category=%q, want %q", got, want)
 		}
 		f, hdr, err := req.FormFile("media")
 		if err != nil {
 			t.Errorf("/1.1/media/upload.json: error getting image file: %v", err)
 			return
 		}
 		if got, want := hdr.Filename, "image.png"; got != want {
 			t.Errorf("/1.1/media/upload.json: got file name=%q, want %q", got, want)
 		}
 		if got, want := mustRead(f), "image-png-bytes"; got != want {
 			t.Errorf("/1.1/media/upload.json: got file content=%q, want %q", got, want)
 			return
 		}
 		mustWrite(w, `{"media_id_string": "media-123"}`)
 	})
 	mux.HandleFunc("api.twitter.com/2/tweets", func(w http.ResponseWriter, req *http.Request) {
 		if got, want := req.Method, http.MethodPost; got != want {
 			t.Errorf("/2/tweets: got method %s, want %s", got, want)
 			return
 		}
 		if got, want := req.Header.Get("Content-Type"), "application/json"; got != want {
 			t.Errorf("/2/tweets: got Content-Type=%q, want %q", got, want)
 			return
 		}
 		var v struct {
 			Text  string `json:"text"`
 			Media struct {
 				MediaIDs []string `json:"media_ids"`
 			} `json:"media"`
 		}
 		if err := json.NewDecoder(req.Body).Decode(&v); err != nil {
 			t.Errorf("/2/tweets: decode JSON error: %v", err)
 			return
 		}
 		if got, want := v.Text, "tweet-text"; got != want {
 			t.Errorf("/2/tweets: got status=%q, want %q", got, want)
 		}
 		if got, want := v.Media.MediaIDs, []string{"media-123"}; !reflect.DeepEqual(got, want) {
 			t.Errorf("/2/tweets: got media_ids=%q, want %q", got, want)
 		}
 		w.WriteHeader(http.StatusCreated)
 		mustWrite(w, `{"data": {"id": "tweet-123"}}`)
 	})
 	cl := realTwitterClient{twitterAPI: &http.Client{Transport: localRoundTripper{mux}}}

 	tweetURL, err := cl.PostTweet("tweet-text", []byte("image-png-bytes"), "alt text")
 	if err != nil {
 		t.Fatal("PostTweet:", err)
 	}
 	if got, want := tweetURL, "https://twitter.com/username/status/tweet-123"; got != want {
 		t.Errorf("got tweetURL=%q, want %q", got, want)
 	}
 }

 // localRoundTripper is an http.RoundTripper that executes HTTP transactions
 // by using handler directly, instead of going over an HTTP connection.
 type localRoundTripper struct {
 	handler http.Handler
 }

 func (l localRoundTripper) RoundTrip(req *http.Request) (*http.Response, error) {
 	w := httptest.NewRecorder()
 	l.handler.ServeHTTP(w, req)
 	return w.Result(), nil
 }

 func mustRead(r io.Reader) string {
 	b, err := io.ReadAll(r)
 	if err != nil {
 		panic(err)
 	}
 	return string(b)
 }

 func mustWrite(w io.Writer, s string) {
 	_, err := io.WriteString(w, s)
 	if err != nil {
 		panic(err)
 	}
 }
	// Copyright 2021 The Go Authors. All rights reserved.
	// Use of this source code is governed by a BSD-style
	// license that can be found in the LICENSE file.

	package task

	import (
	"bytes"
	"context"
	"encoding/json"
	"flag"
	"fmt"
	"image"
	"image/png"
	"io"
	"net/http"
	"net/http/httptest"
	"os"
	"path/filepath"
	"reflect"
	"strings"
	"testing"

	"github.com/google/go-cmp/cmp"
	"golang.org/x/build/buildenv"
	"golang.org/x/build/internal/secret"
	"golang.org/x/build/internal/workflow"
	)

	var postTests = [...]struct {
	name string
	kind ReleaseKind
	published []Published
	security string
	announcement string
	randomSeed int64
	wantLog string
	}{
	{
	name: "minor",
	kind: KindMinor,
	published: []Published{
	{Version: "go1.17.1", Files: []WebsiteFile{{
	OS: "linux", Arch: "arm64",
	Filename: "go1.17.1.linux-arm64.tar.gz", Size: 102606384, Kind: "archive"}},
	},
	{Version: "go1.16.8"},
	},
	security: "Includes security fixes for A and B.",
	announcement: "https://groups.google.com/g/golang-announce/c/dx9d7IOseHw/m/KNH37k37AAAJ",
	randomSeed: 234,
	wantLog: `tweet text:
	🎊 Go 1.17.1 and 1.16.8 are released!

	🔐 Security: Includes security fixes for A and B.

	📢 Announcement: https://groups.google.com/g/golang-announce/c/dx9d7IOseHw/m/KNH37k37AAAJ

	⬇️ Download: https://go.dev/dl/#go1.17.1

	#golang
	tweet image:
	$ go install golang.org/dl/go1.17.1@latest
	$ go1.17.1 download
	Downloaded 0.0% ( 0 / 102606384 bytes) ...
	Downloaded 50.0% ( 51303192 / 102606384 bytes) ...
	Downloaded 100.0% (102606384 / 102606384 bytes)
	Unpacking go1.17.1.linux-arm64.tar.gz ...
	Success. You may now run 'go1.17.1'
	$ go1.17.1 version
	go version go1.17.1 linux/arm64` + "\n",
	},
	{
	name: "minor-solo",
	kind: KindMinor,
	published: []Published{{Version: "go1.11.1", Files: []WebsiteFile{{
	OS: "darwin", Arch: "amd64",
	Filename: "go1.11.1.darwin-amd64.tar.gz", Size: 124181190, Kind: "archive"}},
	}},
	announcement: "https://groups.google.com/g/golang-announce/c/pFXKAfoVJqw",
	randomSeed: 23,
	wantLog: `tweet text:
	🎆 Go 1.11.1 is released!

	📣 Announcement: https://groups.google.com/g/golang-announce/c/pFXKAfoVJqw

	📦 Download: https://go.dev/dl/#go1.11.1

	#golang
	tweet image:
	$ go install golang.org/dl/go1.11.1@latest
	$ go1.11.1 download
	Downloaded 0.0% ( 0 / 124181190 bytes) ...
	Downloaded 50.0% ( 62090595 / 124181190 bytes) ...
	Downloaded 100.0% (124181190 / 124181190 bytes)
	Unpacking go1.11.1.darwin-amd64.tar.gz ...
	Success. You may now run 'go1.11.1'
	$ go1.11.1 version
	go version go1.11.1 darwin/amd64` + "\n",
	},
	{
	name: "beta",
	kind: KindBeta,
	published: []Published{{Version: "go1.17beta1", Files: []WebsiteFile{{
	OS: "darwin", Arch: "amd64",
	Filename: "go1.17beta1.darwin-amd64.tar.gz", Size: 135610703, Kind: "archive"}},
	}},
	announcement: "https://groups.google.com/g/golang-announce/c/i4EliPDV9Ok/m/MxA-nj53AAAJ",
	randomSeed: 678,
	wantLog: `tweet text:
	⚡️ Go 1.17 Beta 1 is released!

	⚙️ Try it! File bugs! https://go.dev/issue/new

	🗣 Announcement: https://groups.google.com/g/golang-announce/c/i4EliPDV9Ok/m/MxA-nj53AAAJ

	📦 Download: https://go.dev/dl/#go1.17beta1

	#golang
	tweet image:
	$ go install golang.org/dl/go1.17beta1@latest
	$ go1.17beta1 download
	Downloaded 0.0% ( 0 / 135610703 bytes) ...
	Downloaded 50.0% ( 67805351 / 135610703 bytes) ...
	Downloaded 100.0% (135610703 / 135610703 bytes)
	Unpacking go1.17beta1.darwin-amd64.tar.gz ...
	Success. You may now run 'go1.17beta1'
	$ go1.17beta1 version
	go version go1.17beta1 darwin/amd64` + "\n",
	},
	{
	name: "rc",
	kind: KindRC,
	published: []Published{{Version: "go1.17rc2", Files: []WebsiteFile{{
	OS: "windows", Arch: "arm64",
	Filename: "go1.17rc2.windows-arm64.zip", Size: 116660997, Kind: "archive"}},
	}},
	announcement: "https://groups.google.com/g/golang-announce/c/yk30ovJGXWY/m/p9uUnKbbBQAJ",
	randomSeed: 456,
	wantLog: `tweet text:
	🎉 Go 1.17 Release Candidate 2 is released!

	🏖 Run it in dev! Run it in prod! File bugs! https://go.dev/issue/new

	🔈 Announcement: https://groups.google.com/g/golang-announce/c/yk30ovJGXWY/m/p9uUnKbbBQAJ

	📦 Download: https://go.dev/dl/#go1.17rc2

	#golang
	tweet image:
	$ go install golang.org/dl/go1.17rc2@latest
	$ go1.17rc2 download
	Downloaded 0.0% ( 0 / 116660997 bytes) ...
	Downloaded 50.0% ( 58330498 / 116660997 bytes) ...
	Downloaded 100.0% (116660997 / 116660997 bytes)
	Unpacking go1.17rc2.windows-arm64.zip ...
	Success. You may now run 'go1.17rc2'
	$ go1.17rc2 version
	go version go1.17rc2 windows/arm64` + "\n",
	},
	{
	name: "major",
	kind: KindMajor,
	published: []Published{{Version: "go1.21.0", Files: []WebsiteFile{{
	OS: "freebsd", Arch: "amd64",
	Filename: "go1.21.0.freebsd-amd64.tar.gz", Size: 133579378, Kind: "archive"}},
	}},
	security: "Includes a super duper security fix (CVE-123).",
	randomSeed: 123,
	wantLog: `tweet text:
	🥳 Go 1.21.0 is released!

	🔐 Security: Includes a super duper security fix (CVE-123).

	📝 Release notes: https://go.dev/doc/go1.21

	📦 Download: https://go.dev/dl/#go1.21.0

	#golang
	tweet image:
	$ go install golang.org/dl/go1.21.0@latest
	$ go1.21.0 download
	Downloaded 0.0% ( 0 / 133579378 bytes) ...
	Downloaded 50.0% ( 66789689 / 133579378 bytes) ...
	Downloaded 100.0% (133579378 / 133579378 bytes)
	Unpacking go1.21.0.freebsd-amd64.tar.gz ...
	Success. You may now run 'go1.21.0'
	$ go1.21.0 version
	go version go1.21.0 freebsd/amd64` + "\n",
	},
	}

	func TestTweetRelease(t *testing.T) {
	for _, tc := range postTests {
	t.Run(tc.name, func(t *testing.T) {
	// Call the tweet task function in dry-run mode so it
	// doesn't actually try to tweet, but capture its log.
	var buf bytes.Buffer
	ctx := &workflow.TaskContext{Context: context.Background(), Logger: fmtWriter{&buf}}
	tweetURL, err := (SocialMediaTasks{RandomSeed: tc.randomSeed}).TweetRelease(ctx, tc.kind, tc.published, tc.security, tc.announcement)
	if err != nil {
	t.Fatal("got a non-nil error:", err)
	}
	if got, want := tweetURL, "(dry-run)"; got != want {
	t.Errorf("unexpected tweetURL: got = %q, want %q", got, want)
	}
	if diff := cmp.Diff(tc.wantLog, buf.String()); diff != "" {
	t.Errorf("log mismatch (-want +got):\n%s", diff)
	}
	})
	}
	}

	type fmtWriter struct{ w io.Writer }

	func (f fmtWriter) Printf(format string, v ...interface{}) {
	fmt.Fprintf(f.w, format, v...)
	}

	var mastodonAPI secret.MastodonCredentials
	var secretErr error
	var mastodonPMTarget = flag.String("mastodon", "", "Name of account to receive private message (e.g., @user@instance.suffix)")

	func init() {
	secretErr = secret.InitFlagSupport(context.Background())
	secret.JSONVarFlag(&mastodonAPI, "mastodon-api-secret", "Mastodon API secret to use for tests that post.")
	flag.Set("mastodon-api-secret", fmt.Sprintf("secret:%s/%s", buildenv.Production.ProjectName, secret.NameMastodonAPISecret))
	}

	var updateFlag = flag.Bool("update", false, "Update golden files.")

	func TestDrawTerminal(t *testing.T) {
	got, err := drawTerminal(`$ go install golang.org/dl/go1.18beta1@latest
	$ go1.18beta1 download
	Downloaded 0.0% ( 0 / 111109966 bytes) ...
	Downloaded 50.0% ( 55554983 / 111109966 bytes) ...
	Downloaded 100.0% (111109966 / 111109966 bytes)
	Unpacking go1.18beta1.linux-s390x.tar.gz ...
	Success. You may now run 'go1.18beta1'
	$ go1.18beta1 version
	go version go1.18beta1 linux/s390x`)
	if err != nil {
	t.Fatalf("drawTerminal: got error=%v, want nil", err)
	}
	if *updateFlag {
	encodePNG(t, filepath.Join("testdata", "terminal.png"), got)
	return
	}
	want := decodePNG(t, filepath.Join("testdata", "terminal.png"))
	if !got.Bounds().Eq(want.Bounds()) {
	t.Fatalf("drawTerminal: got image bounds=%v, want %v", got.Bounds(), want.Bounds())
	}
	diff := func(a, b uint32) uint64 {
	if a < b {
	return uint64(b - a)
	}
	return uint64(a - b)
	}
	var total uint64
	for y := 0; y < want.Bounds().Dy(); y++ {
	for x := 0; x < want.Bounds().Dx(); x++ {
	r0, g0, b0, a0 := got.At(x, y).RGBA()
	r1, g1, b1, a1 := want.At(x, y).RGBA()
	const D = 0xffff * 20 / 100 // Diff threshold of 20% for RGB color components.
	if diff(r0, r1) > D \|\| diff(g0, g1) > D \|\| diff(b0, b1) > D \|\| a0 != a1 {
	t.Errorf("at (%d, %d):\n got RGBA %v\nwant RGBA %v", x, y, got.At(x, y), want.At(x, y))
	}
	total += diff(r0, r1) + diff(g0, g1) + diff(b0, b1)
	}
	}
	if testing.Verbose() {
	t.Logf("average pixel color diff: %v%%", 100float64(total)/float64(0xffffwant.Bounds().Dx()*want.Bounds().Dy()))
	}
	}

	func encodePNG(t *testing.T, name string, m image.Image) {
	t.Helper()
	var buf bytes.Buffer
	err := (&png.Encoder{CompressionLevel: png.BestCompression}).Encode(&buf, m)
	if err != nil {
	t.Fatal(err)
	}
	err = os.WriteFile(name, buf.Bytes(), 0644)
	if err != nil {
	t.Fatal(err)
	}
	}

	func decodePNG(t *testing.T, name string) image.Image {
	t.Helper()
	f, err := os.Open(name)
	if err != nil {
	t.Fatal(err)
	}
	defer f.Close()
	m, err := png.Decode(f)
	if err != nil {
	t.Fatal(err)
	}
	return m
	}

	// TestPostToMastodonUsingCredentials always passes unless some invariant is badly wrong.
	// This is intended to allow as-close-to-real testing as possible.
	// It is capable of actual activity on Mastodon, this will be a DM
	// to a specified person, so don't get cute with your example recipient.
	// DO NOT AUTOMATE THIS TEST, IT SHOULD BE RUN BY A HUMAN.
	func TestPostToMastodonUsingCredentials(t *testing.T) {
	pmTarget := strings.TrimSpace(*mastodonPMTarget)
	t.Logf("private message target (-mastodon)=%v", pmTarget)
	t.Logf("mastodonAPI=%v", mastodonAPI)
	if pmTarget == "" {
	t.Skipf("Nothing to do here without a '-mastodon' flag")
	}
	if secretErr != nil {
	t.Skipf("Nothing to do here without access to secrets, err=%v", secretErr)
	}
	if mastodonAPI.Application == "" {
	t.Skipf("Nothing to do here without a valid API key")
	}

	cl, err := NewTestMastodonClient(mastodonAPI, pmTarget)
	if err != nil {
	t.Fatalf("NewTestMastodonClient(%v, %s) error %v", mastodonAPI, pmTarget, err)
	}

	tc := &postTests[0]

	var buf bytes.Buffer
	ctx := &workflow.TaskContext{Context: context.Background(), Logger: fmtWriter{&buf}}
	tweetURL, err := (SocialMediaTasks{RandomSeed: tc.randomSeed, MastodonClient: cl}).TrumpetRelease(ctx, tc.kind, tc.published, tc.security, tc.announcement)
	t.Logf("Mastodon post URL=%v, err=%v", tweetURL, err)
	t.Log(buf.String())
	}

	func TestPostTweet(t *testing.T) {
	mux := http.NewServeMux()
	mux.HandleFunc("upload.twitter.com/1.1/media/upload.json", func(w http.ResponseWriter, req *http.Request) {
	if got, want := req.Method, http.MethodPost; got != want {
	t.Errorf("/1.1/media/upload.json: got method %s, want %s", got, want)
	return
	}
	if got, want := req.FormValue("media_category"), "tweet_image"; got != want {
	t.Errorf("/1.1/media/upload.json: got media_category=%q, want %q", got, want)
	}
	f, hdr, err := req.FormFile("media")
	if err != nil {
	t.Errorf("/1.1/media/upload.json: error getting image file: %v", err)
	return
	}
	if got, want := hdr.Filename, "image.png"; got != want {
	t.Errorf("/1.1/media/upload.json: got file name=%q, want %q", got, want)
	}
	if got, want := mustRead(f), "image-png-bytes"; got != want {
	t.Errorf("/1.1/media/upload.json: got file content=%q, want %q", got, want)
	return
	}
	mustWrite(w, `{"media_id_string": "media-123"}`)
	})
	mux.HandleFunc("api.twitter.com/2/tweets", func(w http.ResponseWriter, req *http.Request) {
	if got, want := req.Method, http.MethodPost; got != want {
	t.Errorf("/2/tweets: got method %s, want %s", got, want)
	return
	}
	if got, want := req.Header.Get("Content-Type"), "application/json"; got != want {
	t.Errorf("/2/tweets: got Content-Type=%q, want %q", got, want)
	return
	}
	var v struct {
	Text string `json:"text"`
	Media struct {
	MediaIDs []string `json:"media_ids"`
	} `json:"media"`
	}
	if err := json.NewDecoder(req.Body).Decode(&v); err != nil {
	t.Errorf("/2/tweets: decode JSON error: %v", err)
	return
	}
	if got, want := v.Text, "tweet-text"; got != want {
	t.Errorf("/2/tweets: got status=%q, want %q", got, want)
	}
	if got, want := v.Media.MediaIDs, []string{"media-123"}; !reflect.DeepEqual(got, want) {
	t.Errorf("/2/tweets: got media_ids=%q, want %q", got, want)
	}
	w.WriteHeader(http.StatusCreated)
	mustWrite(w, `{"data": {"id": "tweet-123"}}`)
	})
	cl := realTwitterClient{twitterAPI: &http.Client{Transport: localRoundTripper{mux}}}

	tweetURL, err := cl.PostTweet("tweet-text", []byte("image-png-bytes"), "alt text")
	if err != nil {
	t.Fatal("PostTweet:", err)
	}
	if got, want := tweetURL, "https://twitter.com/username/status/tweet-123"; got != want {
	t.Errorf("got tweetURL=%q, want %q", got, want)
	}
	}

	// localRoundTripper is an http.RoundTripper that executes HTTP transactions
	// by using handler directly, instead of going over an HTTP connection.
	type localRoundTripper struct {
	handler http.Handler
	}

	func (l localRoundTripper) RoundTrip(req http.Request) (http.Response, error) {
	w := httptest.NewRecorder()
	l.handler.ServeHTTP(w, req)
	return w.Result(), nil
	}

	func mustRead(r io.Reader) string {
	b, err := io.ReadAll(r)
	if err != nil {
	panic(err)
	}
	return string(b)
	}

	func mustWrite(w io.Writer, s string) {
	_, err := io.WriteString(w, s)
	if err != nil {
	panic(err)
	}
	}