feat: tlsmiddlebox experiment (#817)

See https://github.com/ooni/probe/issues/2124

internal/engine/experiment/tlsmiddlebox/utils_test.go

@@ -0,0 +1,46 @@
+package tlsmiddlebox
+
+import (
+	"testing"
+
+	"github.com/google/go-cmp/cmp"
+)
+
+func TestPrepareAddrs(t *testing.T) {
+	type arg struct {
+		addrs []string
+		port  string
+	}
+	tests := []struct {
+		name string
+		args arg
+		want []string
+	}{{
+		name: "with valid input",
+		args: arg{
+			addrs: []string{"1.1.1.1", "2001:4860:4860::8844"},
+			port:  "",
+		},
+		want: []string{"1.1.1.1:443", "[2001:4860:4860::8844]:443"},
+	}, {
+		name: "with invalid input",
+		args: arg{
+			addrs: []string{"1.1.1.1.1", "2001:4860:4860::8844"},
+			port:  "",
+		},
+		want: []string{"[2001:4860:4860::8844]:443"},
+	}, {
+		name: "with custom port",
+		args: arg{
+			addrs: []string{"1.1.1.1", "2001:4860:4860::8844"},
+			port:  "80",
+		},
+		want: []string{"1.1.1.1:80", "[2001:4860:4860::8844]:80"},
+	}}
+	for _, tt := range tests {
+		out := prepareAddrs(tt.args.addrs, tt.args.port)
+		if diff := cmp.Diff(out, tt.want); diff != "" {
+			t.Fatal(diff)
+		}
+	}
+}