feat: dedupe geoip rules

internal/corecfg/manager_test.go

@@ -31,3 +31,30 @@ func TestDedupeMatchRuleNonList(t *testing.T) {
 		t.Fatalf("expected nil passthrough, got %#v", got)
 	}
 }
+
+func TestDedupeGeoIPRule(t *testing.T) {
+	rules := []interface{}{
+		"GEOIP,CN,DIRECT",
+		"DOMAIN,example.com,sub-a | Proxy",
+		"GEOIP,CN,sub-b | Proxy,no-resolve",
+		"GEOIP,JP,sub-b | Proxy",
+	}
+
+	got := dedupeGeoIPRule(rules)
+
+	want := []interface{}{
+		"DOMAIN,example.com,sub-a | Proxy",
+		"GEOIP,CN,sub-b | Proxy,no-resolve",
+		"GEOIP,JP,sub-b | Proxy",
+	}
+
+	if !reflect.DeepEqual(got, want) {
+		t.Fatalf("got %#v, want %#v", got, want)
+	}
+}
+
+func TestDedupeGeoIPRuleNonList(t *testing.T) {
+	if got := dedupeGeoIPRule(nil); got != nil {
+		t.Fatalf("expected nil passthrough, got %#v", got)
+	}
+}