package main

import (
	"go/parser"
	"go/token"
	"strings"
	"testing"
)

func TestFormatWidths(t *testing.T) {
	source := `package main
func main() {
 println("first argument", "second argument", "third argument", "fourth argument")
}
`
	var narrow, wide string
	for width := 40; width <= 180; width += 5 {
		output, err := formatSource(source, width)
		if err != nil {
			t.Fatalf("width %d: %v", width, err)
		}
		if _, err := parser.ParseFile(token.NewFileSet(), "output.go", output, parser.AllErrors); err != nil {
			t.Fatalf("width %d produced invalid Go: %v", width, err)
		}
		if width == 40 {
			narrow = string(output)
		}
		if width == 180 {
			wide = string(output)
		}
	}
	if strings.Count(narrow, "\n") <= strings.Count(wide, "\n") {
		t.Fatal("narrow width did not split the call")
	}
}

func TestInvalidSource(t *testing.T) {
	if _, err := formatSource("package main\nfunc {", 100); err == nil {
		t.Fatal("expected a syntax error")
	}
	// A failed edit must not prevent subsequent formatting.
	if _, err := formatSource("package main\nfunc main() {}", 100); err != nil {
		t.Fatal(err)
	}
}