diff --git a/internal/model/model_test.go b/internal/model/model_test.go
new file mode 100644
index 0000000..5e3bf64
--- /dev/null
+++ b/internal/model/model_test.go
@@ -0,0 +1,63 @@
+package model
+
+import "testing"
+
+func TestParseElement(t *testing.T) {
+	tests := []struct {
+		in       string
+		wantZone string
+		wantSel  SelectorKind
+		wantRef  string
+		wantErr  bool
+	}{
+		{in: "loc", wantZone: "loc", wantSel: SelNone},
+		{in: "  net  ", wantZone: "net", wantSel: SelNone},
+		{in: "net:+asn_cloudflare", wantZone: "net", wantSel: SelIPSet, wantRef: "asn_cloudflare"},
+		{in: "dmz:&api.partner", wantZone: "dmz", wantSel: SelFQDN, wantRef: "api.partner"},
+		{in: "net: +office", wantZone: "net", wantSel: SelIPSet, wantRef: "office"},
+
+		// Bare selectors must be rejected: a selector always needs a zone.
+		{in: "+office", wantErr: true},
+		{in: "&host", wantErr: true},
+		{in: "asn:13335", wantErr: true}, // no + or & sigil -> invalid selector
+		{in: "", wantErr: true},
+		{in: "net:", wantErr: true},
+		{in: ":+office", wantErr: true},
+		{in: "net:+", wantErr: true},
+	}
+
+	for _, tt := range tests {
+		got, err := ParseElement(tt.in)
+		if tt.wantErr {
+			if err == nil {
+				t.Errorf("ParseElement(%q): expected error, got %+v", tt.in, got)
+			}
+			continue
+		}
+		if err != nil {
+			t.Errorf("ParseElement(%q): unexpected error: %v", tt.in, err)
+			continue
+		}
+		if got.Zone != tt.wantZone || got.Selector != tt.wantSel || got.Ref != tt.wantRef {
+			t.Errorf("ParseElement(%q) = %+v, want zone=%q sel=%q ref=%q",
+				tt.in, got, tt.wantZone, tt.wantSel, tt.wantRef)
+		}
+	}
+}
+
+func TestAddressGroupSetName(t *testing.T) {
+	cases := []struct {
+		group AddressGroup
+		want  string
+	}{
+		{AddressGroup{Name: "asn_cloudflare", Type: GroupASN}, "asn_cloudflare"},
+		{AddressGroup{Name: "cloudflare", Type: GroupASN}, "asn_cloudflare"},
+		{AddressGroup{Name: "office", Type: GroupStatic}, "office"},
+		{AddressGroup{Name: "vpn", Type: GroupDNS}, "vpn"},
+	}
+	for _, c := range cases {
+		if got := c.group.SetName(); got != c.want {
+			t.Errorf("SetName(%+v) = %q, want %q", c.group, got, c.want)
+		}
+	}
+}