add version comparer helper

Signed-off-by: Kristoffer Dalby <[email protected]>

hscontrol/util/util.go

@@ -0,0 +1,14 @@
+package util
+
+import "tailscale.com/util/cmpver"
+
+func TailscaleVersionNewerOrEqual(minimum, toCheck string) bool {
+	if cmpver.Compare(minimum, toCheck) <= 0 ||
+		toCheck == "unstable" ||
+		toCheck == "head" {
+
+		return true
+	}
+
+	return false
+}

hscontrol/util/util_test.go

@@ -0,0 +1,95 @@
+package util
+
+import "testing"
+
+func TestTailscaleVersionNewerOrEqual(t *testing.T) {
+	type args struct {
+		minimum string
+		toCheck string
+	}
+	tests := []struct {
+		name string
+		args args
+		want bool
+	}{
+		{
+			name: "is-equal",
+			args: args{
+				minimum: "1.56",
+				toCheck: "1.56",
+			},
+			want: true,
+		},
+		{
+			name: "is-newer-head",
+			args: args{
+				minimum: "1.56",
+				toCheck: "head",
+			},
+			want: true,
+		},
+		{
+			name: "is-newer-unstable",
+			args: args{
+				minimum: "1.56",
+				toCheck: "unstable",
+			},
+			want: true,
+		},
+		{
+			name: "is-newer-patch",
+			args: args{
+				minimum: "1.56.1",
+				toCheck: "1.56.1",
+			},
+			want: true,
+		},
+		{
+			name: "is-older-patch-same-minor",
+			args: args{
+				minimum: "1.56.1",
+				toCheck: "1.56.0",
+			},
+			want: false,
+		},
+		{
+			name: "is-older-unstable",
+			args: args{
+				minimum: "1.56",
+				toCheck: "1.55",
+			},
+			want: false,
+		},
+		{
+			name: "is-older-one-stable",
+			args: args{
+				minimum: "1.56",
+				toCheck: "1.54",
+			},
+			want: false,
+		},
+		{
+			name: "is-older-five-stable",
+			args: args{
+				minimum: "1.56",
+				toCheck: "1.46",
+			},
+			want: false,
+		},
+		{
+			name: "is-older-patch",
+			args: args{
+				minimum: "1.56",
+				toCheck: "1.48.1",
+			},
+			want: false,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := TailscaleVersionNewerOrEqual(tt.args.minimum, tt.args.toCheck); got != tt.want {
+				t.Errorf("TailscaleVersionNewerThan() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}