diff --git a/internal/task/tweet_test.go b/internal/task/tweet_test.go
new file mode 100644
index 0000000..91d21fb
--- /dev/null
+++ b/internal/task/tweet_test.go
@@ -0,0 +1,175 @@
+// 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_test
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+	"io"
+	"testing"
+
+	"golang.org/x/build/internal/task"
+	"golang.org/x/build/internal/workflow"
+)
+
+func TestTweetRelease(t *testing.T) {
+	if testing.Short() {
+		// This test is useful when modifying the tweet text and image templates,
+		// but don't run it in -short mode since tweetImage involves making some
+		// HTTP GET requests to the internet.
+		t.Skip("skipping test that hits golang.org/dl/?mode=json read-only API in -short mode")
+	}
+
+	tests := [...]struct {
+		name    string
+		taskFn  func(workflow.TaskContext, task.ReleaseTweet, bool) (string, error)
+		in      task.ReleaseTweet
+		wantLog string
+	}{
+		{
+			name:   "minor",
+			taskFn: task.TweetMinorRelease,
+			in: task.ReleaseTweet{
+				Version:          "go1.17.1",
+				SecondaryVersion: "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://golang.org/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:   "beta",
+			taskFn: task.TweetBetaRelease,
+			in: task.ReleaseTweet{
+				Version:      "go1.17beta1",
+				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://golang.org/issue/new
+
+🗣 Announcement: https://groups.google.com/g/golang-announce/c/i4EliPDV9Ok/m/MxA-nj53AAAJ
+
+📦 Download: https://golang.org/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",
+			taskFn: task.TweetRCRelease,
+			in: task.ReleaseTweet{
+				Version:      "go1.17rc2",
+				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://golang.org/issue/new
+
+🔈 Announcement: https://groups.google.com/g/golang-announce/c/yk30ovJGXWY/m/p9uUnKbbBQAJ
+
+📦 Download: https://golang.org/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",
+			taskFn: task.TweetMajorRelease,
+			in: task.ReleaseTweet{
+				Version:    "go1.17",
+				Security:   "Includes a super duper security fix (CVE-123).",
+				RandomSeed: 123,
+			},
+			wantLog: `tweet text:
+🥳 Go go1.17 is released!
+
+🔐 Security: Includes a super duper security fix (CVE-123).
+
+📝 Release notes: https://golang.org/doc/go1.17
+
+📦 Download: https://golang.org/dl/#go1.17
+
+#golang
+tweet image:
+$ go install golang.org/dl/go1.17@latest
+$ go1.17 download
+Downloaded   0.0% (        0 / 133579378 bytes) ...
+Downloaded  50.0% ( 66789689 / 133579378 bytes) ...
+Downloaded 100.0% (133579378 / 133579378 bytes)
+Unpacking go1.17.freebsd-amd64.tar.gz ...
+Success. You may now run 'go1.17'
+$ go1.17 version
+go version go1.17 freebsd/amd64` + "\n",
+		},
+	}
+	for _, tc := range tests {
+		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 := tc.taskFn(ctx, tc.in, true)
+			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 got, want := buf.String(), tc.wantLog; got != want {
+				t.Errorf("unexpected log: got = %q, want %q", got, want)
+			}
+		})
+	}
+}
+
+type fmtWriter struct{ w io.Writer }
+
+func (f fmtWriter) Printf(format string, v ...interface{}) {
+	fmt.Fprintf(f.w, format, v...)
+}