diff --git a/core/commands2/diag_test.go b/core/commands2/diag_test.go
new file mode 100644
index 000000000..5e6c383e2
--- /dev/null
+++ b/core/commands2/diag_test.go
@@ -0,0 +1,29 @@
+package commands
+
+import (
+	"bytes"
+	"testing"
+)
+
+func TestPrintDiagnostics(t *testing.T) {
+	output := DiagnosticOutput{
+		Peers: []DiagnosticPeer{
+			DiagnosticPeer{ID: "QmNrjRuUtBNZAigzLRdZGN1YCNUxdF2WY2HnKyEFJqoTeg",
+				UptimeSeconds: 14,
+				Connections: []DiagnosticConnection{
+					DiagnosticConnection{ID: "QmNrjRuUtBNZAigzLRdZGN1YCNUxdF2WY2HnKyEFJqoTeg",
+						NanosecondsLatency: 1347899,
+					},
+				},
+			},
+			DiagnosticPeer{ID: "QmUaUZDp6QWJabBYSKfiNmXLAXD8HNKnWZh9Zoz6Zri9Ti",
+				UptimeSeconds: 14,
+			},
+		},
+	}
+	var buf bytes.Buffer
+	if err := printDiagnostics(&buf, &output); err != nil {
+		t.Fatal(err)
+	}
+	t.Log(buf.String())
+}