config: add test for balance configs (#1048)

Author: djshow832

lib/config/balance_test.go

@@ -0,0 +1,51 @@
+// Copyright 2025 PingCAP, Inc.
+// SPDX-License-Identifier: Apache-2.0
+
+package config
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestCheckBalance(t *testing.T) {
+	balances := []Balance{
+		{
+			Policy: "test",
+		},
+		{
+			RoutingPolicy: "test",
+		},
+		{
+			Status: Factor{MigrationsPerSecond: -1},
+		},
+		{
+			Health: Factor{MigrationsPerSecond: -1},
+		},
+		{
+			Memory: Factor{MigrationsPerSecond: -1},
+		},
+		{
+			CPU: Factor{MigrationsPerSecond: -1},
+		},
+		{
+			Location: Factor{MigrationsPerSecond: -1},
+		},
+		{
+			ConnCount: ConnCountFactor{Factor: Factor{MigrationsPerSecond: -1}},
+		},
+		{
+			ConnCount: ConnCountFactor{CountRatioThreshold: -1},
+		},
+	}
+
+	for i, balance := range balances {
+		require.Error(t, balance.Check(), "%d", i)
+	}
+
+	balance := Balance{}
+	require.NoError(t, (&balance).Check())
+	balance = DefaultBalance()
+	require.NoError(t, (&balance).Check())
+}