diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 540f5b0..9ff5789 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -20,8 +20,9 @@ jobs:
           git diff --exit-code
           go vet ./...
 
-      - name: Build project
+      - name: Build and test project
         run: |
+          go test ./...
           mkdir bin
           GOBIN="$PWD/bin" CGO_ENABLED=0 go install ./...
 
diff --git a/etcdconfigweb/config.go b/etcdconfigweb/config.go
index d974903..a2b91c4 100644
--- a/etcdconfigweb/config.go
+++ b/etcdconfigweb/config.go
@@ -34,6 +34,31 @@ var MISSING_V6MTU = errors.New("Missing v6mtu query parameter")
 var MISSING_PUBKEY = errors.New("Missing pubkey query parameter")
 var MISSING_NONCE = errors.New("Missing nonce query parameter")
 
+func generateNodeAddressesAndRanges(info *ffbs.NodeInfo) {
+	const V4_BASE uint32 = 10 << 24
+	const V4_RANGE_SIZE uint8 = 10
+	const V6_BASE_HIGH uint64 = 0x20010bf70381 << 16
+
+	num := *info.ID
+
+	var v4Addr [net.IPv4len]byte
+	binary.BigEndian.PutUint32(v4Addr[:], V4_BASE|(uint32(num)<<V4_RANGE_SIZE))
+	v4range := fmt.Sprintf("%s/%d", net.IP(v4Addr[:]), 8*net.IPv4len-V4_RANGE_SIZE)
+	v4Addr[net.IPv4len-1] = 1
+	v4addr := net.IP(v4Addr[:]).String()
+
+	var v6Addr [net.IPv6len]byte
+	binary.BigEndian.PutUint64(v6Addr[:8], V6_BASE_HIGH|uint64(num))
+	v6range := fmt.Sprintf("%s/64", net.IP(v6Addr[:]))
+	v6Addr[net.IPv6len-1] = 1
+	v6addr := net.IP(v6Addr[:]).String()
+
+	info.Address4 = &v4addr
+	info.Range4 = &v4range
+	info.Address6 = &v6addr
+	info.Range6 = &v6range
+}
+
 func (ch ConfigHandler) handleRequest(ctx context.Context, query url.Values, headers http.Header) (*ConfigResponse, error) {
 	var v6mtu uint64
 	var err error
@@ -80,30 +105,7 @@ func (ch ConfigHandler) handleRequest(ctx context.Context, query url.Values, hea
 		}
 
 		// insert new node
-		err := ch.etcdHandler.CreateNode(ctx, pubkey, func(info *ffbs.NodeInfo) {
-			const V4_BASE uint32 = 10 << 24
-			const V4_RANGE_SIZE uint8 = 10
-			const V6_BASE_HIGH uint64 = 0x20010bf70381 << 16
-
-			num := *info.ID
-
-			var v4Addr [net.IPv4len]byte
-			binary.BigEndian.PutUint32(v4Addr[:], V4_BASE|(uint32(num)<<V4_RANGE_SIZE))
-			v4range := fmt.Sprintf("%s/%d", net.IP(v4Addr[:]), 8*net.IPv4len-V4_RANGE_SIZE)
-			v4Addr[net.IPv4len-1] = 1
-			v4addr := net.IP(v4Addr[:]).String()
-
-			var v6Addr [net.IPv6len]byte
-			binary.BigEndian.PutUint64(v6Addr[:8], V6_BASE_HIGH|uint64(num))
-			v6range := fmt.Sprintf("%s/64", net.IP(v6Addr[:]))
-			v6Addr[net.IPv6len-1] = 1
-			v6addr := net.IP(v6Addr[:]).String()
-
-			info.Address4 = &v4addr
-			info.Range4 = &v4range
-			info.Address6 = &v6addr
-			info.Range6 = &v6range
-		})
+		err := ch.etcdHandler.CreateNode(ctx, pubkey, generateNodeAddressesAndRanges)
 		if err != nil {
 			return nil, err
 		}
diff --git a/etcdconfigweb/config_test.go b/etcdconfigweb/config_test.go
new file mode 100644
index 0000000..0581511
--- /dev/null
+++ b/etcdconfigweb/config_test.go
@@ -0,0 +1,31 @@
+package main
+
+import (
+	"testing"
+
+	"github.com/ffbs/etcd-tools/ffbs"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestGenerateAddressesAndRanges(t *testing.T) {
+	// Using https://freifunk-bs.de/map/#!/de/map/f4068dcf9fe1 as an example
+	id := uint64(30)
+	node := ffbs.NodeInfo{ID: &id}
+	generateNodeAddressesAndRanges(&node)
+	assert.Equal(t, "10.0.120.1", *node.Address4)
+	assert.Equal(t, "10.0.120.0/22", *node.Range4)
+	assert.Equal(t, "2001:bf7:381:1e::1", *node.Address6)
+	assert.Equal(t, "2001:bf7:381:1e::/64", *node.Range6)
+}
+
+func TestGenerateHighestAddressesAndRanges(t *testing.T) {
+	// IPv4 base range is /8. Range of every subnet is /22 => 22-8 = 14 bits of freedom
+	id := uint64(16383)
+	node := ffbs.NodeInfo{ID: &id}
+	generateNodeAddressesAndRanges(&node)
+	assert.Equal(t, "10.255.252.1", *node.Address4)
+	assert.Equal(t, "10.255.252.0/22", *node.Range4)
+	assert.Equal(t, "2001:bf7:381:3fff::1", *node.Address6)
+	assert.Equal(t, "2001:bf7:381:3fff::/64", *node.Range6)
+}
diff --git a/go.mod b/go.mod
index 57e1d66..b70dbf5 100644
--- a/go.mod
+++ b/go.mod
@@ -6,6 +6,7 @@ toolchain go1.22.9
 
 require (
 	github.com/spf13/cobra v1.8.1
+	github.com/stretchr/testify v1.9.0
 	go.etcd.io/etcd/client/v3 v3.5.17
 	go.seankhliao.com/signify v0.0.0-20200507101447-944db0e32d56
 	golang.zx2c4.com/wireguard/wgctrl v0.0.0-20230429144221-925a1e7659e6
@@ -14,6 +15,7 @@ require (
 require (
 	github.com/coreos/go-semver v0.3.0 // indirect
 	github.com/coreos/go-systemd/v22 v22.3.2 // indirect
+	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/ebfe/bcrypt_pbkdf v0.0.0-20140212075826-3c8d2dcb253a // indirect
 	github.com/gogo/protobuf v1.3.2 // indirect
 	github.com/golang/protobuf v1.5.4 // indirect
@@ -23,6 +25,7 @@ require (
 	github.com/mdlayher/genetlink v1.3.2 // indirect
 	github.com/mdlayher/netlink v1.7.2 // indirect
 	github.com/mdlayher/socket v0.4.1 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
 	github.com/spf13/pflag v1.0.5 // indirect
 	go.etcd.io/etcd/api/v3 v3.5.17 // indirect
 	go.etcd.io/etcd/client/pkg/v3 v3.5.17 // indirect
@@ -40,4 +43,5 @@ require (
 	google.golang.org/genproto/googleapis/rpc v0.0.0-20230822172742-b8732ec3820d // indirect
 	google.golang.org/grpc v1.59.0 // indirect
 	google.golang.org/protobuf v1.33.0 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
 )
diff --git a/go.sum b/go.sum
index c2042db..2596a95 100644
--- a/go.sum
+++ b/go.sum
@@ -108,6 +108,7 @@ google.golang.org/grpc v1.59.0 h1:Z5Iec2pjwb+LEOqzpB2MR12/eKFhDPhuqW91O+4bwUk=
 google.golang.org/grpc v1.59.0/go.mod h1:aUPDwccQo6OTjy7Hct4AfBPD1GptF4fyUjIkQ9YtF98=
 google.golang.org/protobuf v1.33.0 h1:uNO2rsAINq/JlFpSdYEKIZ0uKD/R9cpdv0T+yoGwGmI=
 google.golang.org/protobuf v1.33.0/go.mod h1:c6P6GXX6sHbq/GpV6MGZEdwhWPcYBgnhAHhKbcUYpos=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/yaml.v2 v2.2.8/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 gopkg.in/yaml.v2 v2.4.0 h1:D8xgwECY7CYvx+Y2n4sBz93Jn9JRvxdiyyo8CTfuKaY=