diff --git a/cmd/tapir/uploads_converter_test.go b/cmd/tapir/uploads_converter_test.go
new file mode 100644
index 0000000..a8bde82
--- /dev/null
+++ b/cmd/tapir/uploads_converter_test.go
@@ -0,0 +1,26 @@
+package main
+
+import (
+	"testing"
+	"time"
+
+	"git.d-ma.be/mathias/tapir/internal/config"
+)
+
+// The converter is told the configured maximum, so a file whose header lies about its
+// length cannot become hours of WAV (adversarial review F2).
+
+func TestNewConverter_IsCappedAtTheConfiguredMaximumDuration(t *testing.T) {
+	var cfg config.Config
+	cfg.FFmpegBin = "/usr/local/bin/ffmpeg"
+	cfg.UploadMaxDuration = 90 * time.Minute
+
+	c := newConverter(cfg)
+
+	if c.Bin != "/usr/local/bin/ffmpeg" {
+		t.Errorf("Bin = %q", c.Bin)
+	}
+	if c.MaxSeconds != 5400 {
+		t.Errorf("MaxSeconds = %v, want 5400", c.MaxSeconds)
+	}
+}