diff --git a/metropolis/test/launch/log.go b/metropolis/test/launch/log.go
new file mode 100644
index 0000000..f251d5b
--- /dev/null
+++ b/metropolis/test/launch/log.go
@@ -0,0 +1,25 @@
+// Copyright The Monogon Project Authors.
+// SPDX-License-Identifier: Apache-2.0
+
+package launch
+
+import (
+	"fmt"
+	"strings"
+)
+
+// logf is compatible with the output of ConciseString as used in the Metropolis
+// console log, making the output more readable in unified test logs.
+func logf(f string, args ...any) {
+	formatted := fmt.Sprintf(f, args...)
+	for i, line := range strings.Split(formatted, "\n") {
+		if len(line) == 0 {
+			continue
+		}
+		if i == 0 {
+			fmt.Printf("TT| %20s ! %s\n", "test launch", line)
+		} else {
+			fmt.Printf("TT| %20s | %s\n", "", line)
+		}
+	}
+}