add AnonymizeIP() tests; move goldmark dependency to the optional template subpackage

Author: aine-etke

format/go.mod

@@ -0,0 +1,5 @@
+module github.com/etkecc/go-kit/format
+
+go 1.22
+
+require github.com/yuin/goldmark v1.7.4

format/go.sum

@@ -0,0 +1,2 @@
+github.com/yuin/goldmark v1.7.4 h1:BDXOHExt+A7gwPCJgPIIq7ENvceR7we7rOS9TNoLZeg=
+github.com/yuin/goldmark v1.7.4/go.mod h1:uzxRWxtg69N339t3louHJ7+O03ezfj6PlliRlaOzY1E=

go.mod

@@ -1,5 +1,3 @@
 module github.com/etkecc/go-kit
 
 go 1.22
-
-require github.com/yuin/goldmark v1.7.4

go.sum

@@ -1,2 +0,0 @@
-github.com/yuin/goldmark v1.7.4 h1:BDXOHExt+A7gwPCJgPIIq7ENvceR7we7rOS9TNoLZeg=
-github.com/yuin/goldmark v1.7.4/go.mod h1:uzxRWxtg69N339t3louHJ7+O03ezfj6PlliRlaOzY1E=

ip.go

@@ -26,9 +26,6 @@ func AnonymizeIP(ip string) string {
 
 	// IPv6
 	ipParts := strings.Split(parsedIP.String(), ":")
-	if len(ipParts) > 0 {
-		ipParts[len(ipParts)-1] = "0"
-		return strings.Join(ipParts, ":")
-	}
-	return ip // not an ip
+	ipParts[len(ipParts)-1] = "0"
+	return strings.Join(ipParts, ":")
 }

ip_test.go

@@ -0,0 +1,35 @@
+package kit
+
+import (
+	"testing"
+)
+
+func TestAnonymizeIP(t *testing.T) {
+	tests := []struct {
+		input    string
+		expected string
+	}{
+		{"", ""},
+		{"hello", "hello"},
+		{"192.168.1.42", "192.168.1.0"},
+		{"8.8.8.8", "8.8.8.0"},
+		{"255.255.255.255", "255.255.255.0"},
+		{"0.0.0.0", "0.0.0.0"},
+		{"192.168.1", "192.168.1"},
+		{"::1", "::0"},
+		{"2001:db8::1234", "2001:db8::0"},
+		{"fe80::a6db:30ff:fe98:e946", "fe80::a6db:30ff:fe98:0"},
+		{"2001:db8:abcd:0012:0000:0000:0000:0001", "2001:db8:abcd:12::0"},
+		{"::", "::0"},
+		{"2001:db8:85a3::8a2e:370:7334", "2001:db8:85a3::8a2e:370:0"},
+		{"abcd::", "abcd::0"},
+		{"1:2:3:4:5:6:7:8", "1:2:3:4:5:6:7:0"},
+	}
+
+	for i, tc := range tests {
+		got := AnonymizeIP(tc.input)
+		if got != tc.expected {
+			t.Errorf("case %d: input=%q got=%q want=%q", i, tc.input, got, tc.expected)
+		}
+	}
+}