diff --git a/cmd/gogio/android_test.go b/cmd/gogio/android_test.go
index 3c5cc00d..59c09161 100644
--- a/cmd/gogio/android_test.go
+++ b/cmd/gogio/android_test.go
@@ -3,7 +3,6 @@
 package main_test
 
 import (
-	"bufio"
 	"bytes"
 	"context"
 	"fmt"
@@ -13,7 +12,6 @@ import (
 	"os/exec"
 	"path/filepath"
 	"regexp"
-	"strings"
 )
 
 type AndroidTestDriver struct {
@@ -80,24 +78,16 @@ func (d *AndroidTestDriver) Start(path string) {
 			"-T1",      // don't show prevoius log messages
 			appid+":*", // show all logs from our gio app ID
 		)
-		logcat, err := cmd.StdoutPipe()
+		output, err := cmd.StdoutPipe()
 		if err != nil {
 			d.Fatal(err)
 		}
-		cmd.Stderr = os.Stderr
+		cmd.Stderr = cmd.Stdout
+		d.output = output
 		if err := cmd.Start(); err != nil {
 			d.Fatal(err)
 		}
 		d.Cleanup(cancel)
-		go func() {
-			scanner := bufio.NewScanner(logcat)
-			for scanner.Scan() {
-				line := scanner.Text()
-				if strings.HasSuffix(line, ": frame ready") {
-					d.frameNotifs <- true
-				}
-			}
-		}()
 	}
 
 	// Start the app.
diff --git a/cmd/gogio/e2e_test.go b/cmd/gogio/e2e_test.go
index 33f33892..6bf6a626 100644
--- a/cmd/gogio/e2e_test.go
+++ b/cmd/gogio/e2e_test.go
@@ -3,11 +3,13 @@
 package main_test
 
 import (
+	"bufio"
 	"errors"
 	"flag"
 	"fmt"
 	"image"
 	"image/color"
+	"io"
 	"io/ioutil"
 	"os"
 	"os/exec"
@@ -50,17 +52,13 @@ type driverBase struct {
 
 	width, height int
 
-	// TODO(mvdan): Make this lower-level, so that each driver can simply
-	// send us each line of output from the app. That will let us
-	// deduplicate some code, and also show app output as test logs in a
-	// consistent way.
+	output      io.Reader
 	frameNotifs chan bool
 }
 
 func (d *driverBase) initBase(t *testing.T, width, height int) {
 	d.T = t
 	d.width, d.height = width, height
-	d.frameNotifs = make(chan bool, 1)
 }
 
 func TestEndToEnd(t *testing.T) {
@@ -251,6 +249,32 @@ func checkImageCorners(img image.Image, topLeft, topRight, botLeft, botRight col
 func (d *driverBase) waitForFrame() {
 	d.Helper()
 
+	if d.frameNotifs == nil {
+		// Start the goroutine that reads output lines and notifies of
+		// new frames via frameNotifs. The test doesn't wait for this
+		// goroutine to finish; it will naturally end when the output
+		// reader reaches an error like EOF.
+		d.frameNotifs = make(chan bool, 1)
+		if d.output == nil {
+			d.Fatal("need an output reader to be notified of frames")
+		}
+		go func() {
+			scanner := bufio.NewScanner(d.output)
+			for scanner.Scan() {
+				line := scanner.Text()
+				if strings.Contains(line, "gio frame ready") {
+					d.frameNotifs <- true
+				}
+			}
+			// Since we're only interested in the output while the
+			// app runs, and we don't know when it finishes here,
+			// ignore "already closed" pipe errors.
+			if err := scanner.Err(); err != nil && !errors.Is(err, os.ErrClosed) {
+				d.Errorf("reading app output: %v", err)
+			}
+		}()
+	}
+
 	// Unfortunately, there isn't a way to select on a test failing, since
 	// testing.T doesn't have anything like a context or a "done" channel.
 	//
diff --git a/cmd/gogio/js_test.go b/cmd/gogio/js_test.go
index 94767974..8cb567ea 100644
--- a/cmd/gogio/js_test.go
+++ b/cmd/gogio/js_test.go
@@ -8,10 +8,10 @@ import (
 	"errors"
 	"image"
 	"image/png"
+	"io"
 	"net/http"
 	"net/http/httptest"
 	"os/exec"
-	"strings"
 
 	"github.com/chromedp/cdproto/runtime"
 	"github.com/chromedp/chromedp"
@@ -73,27 +73,26 @@ func (d *JSTestDriver) Start(path string) {
 		}
 		d.Fatal(err)
 	}
+	pr, pw := io.Pipe()
+	d.Cleanup(func() { pw.Close() })
+	d.output = pr
 	chromedp.ListenTarget(ctx, func(ev interface{}) {
 		switch ev := ev.(type) {
 		case *runtime.EventConsoleAPICalled:
-			if ev.Type == "log" && len(ev.Args) == 1 &&
-				// Note that the argument values are JSON.
-				string(ev.Args[0].Value) == `"frame ready"` {
-
-				d.frameNotifs <- true
-				// These logs are expected. Don't show them.
-				break
-			}
 			switch ev.Type {
 			case "log", "info", "warning", "error":
-				var args strings.Builder
+				var b bytes.Buffer
+				b.WriteString("console.")
+				b.WriteString(string(ev.Type))
+				b.WriteString("(")
 				for i, arg := range ev.Args {
 					if i > 0 {
-						args.WriteString(", ")
+						b.WriteString(", ")
 					}
-					args.Write(arg.Value)
+					b.Write(arg.Value)
 				}
-				d.Logf("console %s: %s", ev.Type, args.String())
+				b.WriteString(")\n")
+				pw.Write(b.Bytes())
 			}
 		}
 	})
diff --git a/cmd/gogio/testdata/red.go b/cmd/gogio/testdata/red.go
index eda14907..e925558c 100644
--- a/cmd/gogio/testdata/red.go
+++ b/cmd/gogio/testdata/red.go
@@ -89,7 +89,7 @@ func loop(w *app.Window) error {
 				w.Invalidate()
 			case notifyPrint:
 				notify = notifyNone
-				fmt.Println("frame ready")
+				fmt.Println("gio frame ready")
 			}
 		}
 	}
diff --git a/cmd/gogio/wayland_test.go b/cmd/gogio/wayland_test.go
index e6525165..df10410a 100644
--- a/cmd/gogio/wayland_test.go
+++ b/cmd/gogio/wayland_test.go
@@ -9,7 +9,6 @@ import (
 	"fmt"
 	"image"
 	"image/png"
-	"io"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -137,12 +136,12 @@ func (d *WaylandTestDriver) Start(path string) {
 		ctx, cancel := context.WithCancel(context.Background())
 		cmd := exec.CommandContext(ctx, bin)
 		cmd.Env = []string{"XDG_RUNTIME_DIR=" + d.runtimeDir, "WAYLAND_DISPLAY=" + d.display}
-		stdout, err := cmd.StdoutPipe()
+		output, err := cmd.StdoutPipe()
 		if err != nil {
 			d.Fatal(err)
 		}
-		stderr := &bytes.Buffer{}
-		cmd.Stderr = stderr
+		cmd.Stderr = cmd.Stdout
+		d.output = output
 		if err := cmd.Start(); err != nil {
 			d.Fatal(err)
 		}
@@ -150,21 +149,10 @@ func (d *WaylandTestDriver) Start(path string) {
 		wg.Add(1)
 		go func() {
 			if err := cmd.Wait(); err != nil && ctx.Err() == nil {
-				// Print stderr and error.
-				io.Copy(os.Stdout, stderr)
 				d.Error(err)
 			}
 			wg.Done()
 		}()
-		go func() {
-			scanner := bufio.NewScanner(stdout)
-			for scanner.Scan() {
-				line := scanner.Text()
-				if line == "frame ready" {
-					d.frameNotifs <- true
-				}
-			}
-		}()
 	}
 
 	// Wait for the gio app to render.
diff --git a/cmd/gogio/windows_test.go b/cmd/gogio/windows_test.go
index 91d6a8f7..6c26ed50 100644
--- a/cmd/gogio/windows_test.go
+++ b/cmd/gogio/windows_test.go
@@ -3,11 +3,8 @@
 package main_test
 
 import (
-	"bufio"
-	"bytes"
 	"context"
 	"image"
-	"io"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -95,13 +92,12 @@ func (d *WineTestDriver) Start(path string) {
 			"WINEDEBUG=-all", // hide warnings and other noise
 			"WINEPREFIX=" + wineprefix,
 		}
-		stdout, err := cmd.StdoutPipe()
+		output, err := cmd.StdoutPipe()
 		if err != nil {
 			d.Fatal(err)
 		}
-		stderr := &bytes.Buffer{}
-		cmd.Stderr = stderr
-
+		cmd.Stderr = cmd.Stdout
+		d.output = output
 		if err := cmd.Start(); err != nil {
 			d.Fatal(err)
 		}
@@ -109,22 +105,10 @@ func (d *WineTestDriver) Start(path string) {
 		wg.Add(1)
 		go func() {
 			if err := cmd.Wait(); err != nil && ctx.Err() == nil {
-				// Print stderr and error.
-				io.Copy(os.Stdout, stderr)
 				d.Error(err)
 			}
 			wg.Done()
 		}()
-		go func() {
-			scanner := bufio.NewScanner(stdout)
-			for scanner.Scan() {
-				line := scanner.Text()
-				if line == "frame ready" {
-					d.frameNotifs <- true
-				}
-			}
-		}()
-
 	}
 	// Wait for the gio app to render.
 	d.waitForFrame()
diff --git a/cmd/gogio/x11_test.go b/cmd/gogio/x11_test.go
index f035c914..4549b419 100644
--- a/cmd/gogio/x11_test.go
+++ b/cmd/gogio/x11_test.go
@@ -3,7 +3,6 @@
 package main_test
 
 import (
-	"bufio"
 	"bytes"
 	"context"
 	"fmt"
@@ -47,13 +46,12 @@ func (d *X11TestDriver) Start(path string) {
 		ctx, cancel := context.WithCancel(context.Background())
 		cmd := exec.CommandContext(ctx, bin)
 		cmd.Env = []string{"DISPLAY=" + d.display}
-		stdout, err := cmd.StdoutPipe()
+		output, err := cmd.StdoutPipe()
 		if err != nil {
 			d.Fatal(err)
 		}
-		stderr := &bytes.Buffer{}
-		cmd.Stderr = stderr
-
+		cmd.Stderr = cmd.Stdout
+		d.output = output
 		if err := cmd.Start(); err != nil {
 			d.Fatal(err)
 		}
@@ -61,22 +59,10 @@ func (d *X11TestDriver) Start(path string) {
 		wg.Add(1)
 		go func() {
 			if err := cmd.Wait(); err != nil && ctx.Err() == nil {
-				// Print stderr and error.
-				io.Copy(os.Stdout, stderr)
 				d.Error(err)
 			}
 			wg.Done()
 		}()
-		go func() {
-			scanner := bufio.NewScanner(stdout)
-			for scanner.Scan() {
-				line := scanner.Text()
-				if line == "frame ready" {
-					d.frameNotifs <- true
-				}
-			}
-		}()
-
 	}
 
 	// Wait for the gio app to render.