package runtime

import (
	"os"
	"path/filepath"
	"runtime"
	"testing"
)

func TestModuleKeepsGo122Compatibility(t *testing.T) {
	if runtime.Version() == "" {
		t.Fatal("runtime version unavailable")
	}
	data, err := os.ReadFile(filepath.Join("..", "..", "go.mod"))
	if err != nil {
		t.Fatal(err)
	}
	if !containsLine(string(data), "go 1.22") {
		t.Fatalf("go.mod must keep Go 1.22 compatibility, got:\n%s", data)
	}
}

func containsLine(input string, want string) bool {
	for _, line := range splitLines(input) {
		if line == want {
			return true
		}
	}
	return false
}

func splitLines(input string) []string {
	var lines []string
	start := 0
	for i, char := range input {
		if char == '\n' {
			lines = append(lines, input[start:i])
			start = i + 1
		}
	}
	if start <= len(input) {
		lines = append(lines, input[start:])
	}
	return lines
}