diff --git a/osbase/logtree/unraw/unraw_test.go b/osbase/logtree/unraw/unraw_test.go
new file mode 100644
index 0000000..994e55e
--- /dev/null
+++ b/osbase/logtree/unraw/unraw_test.go
@@ -0,0 +1,138 @@
+package unraw
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"os"
+	"syscall"
+	"testing"
+
+	"source.monogon.dev/osbase/logbuffer"
+	"source.monogon.dev/osbase/logtree"
+	"source.monogon.dev/osbase/supervisor"
+)
+
+func testParser(l *logbuffer.Line, w LeveledWriter) {
+	w(&logtree.ExternalLeveledPayload{
+		Message: l.Data,
+	})
+}
+
+func TestNamedPipeReader(t *testing.T) {
+	dir, err := os.MkdirTemp("/tmp", "metropolis-test-named-pipe-reader")
+	if err != nil {
+		t.Fatalf("could not create tempdir: %v", err)
+	}
+	defer os.RemoveAll(dir)
+	fifoPath := dir + "/fifo"
+
+	// Start named pipe reader.
+	started := make(chan struct{})
+	stop, lt := supervisor.TestHarness(t, func(ctx context.Context) error {
+		converter := Converter{
+			Parser:        testParser,
+			LeveledLogger: supervisor.Logger(ctx),
+		}
+
+		r, err := converter.NamedPipeReader(fifoPath)
+		if err != nil {
+			return fmt.Errorf("could not create pipe reader: %w", err)
+		}
+		close(started)
+		return r(ctx)
+	})
+
+	<-started
+
+	// Open FIFO...
+	f, err := os.OpenFile(fifoPath, os.O_WRONLY, 0)
+	if err != nil {
+		t.Fatalf("could not open fifo: %v", err)
+	}
+
+	// Start reading all logs.
+	reader, err := lt.Read("root", logtree.WithChildren(), logtree.WithStream())
+	if err != nil {
+		t.Fatalf("could not get logtree reader: %v", err)
+	}
+	defer reader.Close()
+
+	// Write two lines to the fifo.
+	fmt.Fprintf(f, "foo\nbar\n")
+	f.Close()
+
+	// Expect lines to end up in logtree.
+	if got, want := (<-reader.Stream).Leveled.MessagesJoined(), "foo"; want != got {
+		t.Errorf("expected first message to be %q, got %q", want, got)
+	}
+	if got, want := (<-reader.Stream).Leveled.MessagesJoined(), "bar"; want != got {
+		t.Errorf("expected second message to be %q, got %q", want, got)
+	}
+
+	// Fully restart the entire supervisor and pipe reader, redo test, things
+	// should continue to work.
+	stop()
+
+	// Block until FIFO isn't being read anymore. This ensures that the
+	// NamedPipeReader actually stopped running, otherwise the following write to
+	// the fifo can race by writing to the old NamedPipeReader and making the test
+	// time out. This can also happen in production, but that will just cause us to
+	// lose piped data in the very small race window when this can happen
+	// (statistically in this test, <0.1%).
+	//
+	// The check is being done by opening the FIFO in 'non-blocking mode', which
+	// returns ENXIO immediately if the FIFO has no corresponding writer, and
+	// succeeds otherwise.
+	for {
+		ft, err := os.OpenFile(fifoPath, os.O_WRONLY|syscall.O_NONBLOCK, 0)
+		if err == nil {
+			// There's still a writer, keep trying.
+			ft.Close()
+		} else if errors.Is(err, syscall.ENXIO) {
+			// No writer, break.
+			break
+		} else {
+			// Something else?
+			t.Fatalf("OpenFile(%q): %v", fifoPath, err)
+		}
+	}
+
+	started = make(chan struct{})
+	stop, lt = supervisor.TestHarness(t, func(ctx context.Context) error {
+		converter := Converter{
+			Parser:        testParser,
+			LeveledLogger: supervisor.Logger(ctx),
+		}
+
+		r, err := converter.NamedPipeReader(fifoPath)
+		if err != nil {
+			return fmt.Errorf("could not create pipe reader: %w", err)
+		}
+		close(started)
+		return r(ctx)
+	})
+	defer stop()
+
+	<-started
+
+	// Start reading all logs.
+	reader, err = lt.Read("root", logtree.WithChildren(), logtree.WithStream())
+	if err != nil {
+		t.Fatalf("could not get logtree reader: %v", err)
+	}
+	defer reader.Close()
+
+	// Write line to the fifo.
+	f, err = os.OpenFile(fifoPath, os.O_WRONLY, 0)
+	if err != nil {
+		t.Fatalf("could not open fifo: %v", err)
+	}
+	fmt.Fprintf(f, "baz\n")
+	f.Close()
+
+	// Expect lines to end up in logtree.
+	if got, want := (<-reader.Stream).Leveled.MessagesJoined(), "baz"; want != got {
+		t.Errorf("expected first message to be %q, got %q", want, got)
+	}
+}