package ledger

import "testing"

func TestParseAmountCanonicalizesExactValues(t *testing.T) {
	for input, expected := range map[string]string{
		"0":                     "0",
		"1":                     "1",
		"1.2300":                "1.23",
		"-0.000000000000000001": "-0.000000000000000001",
		"99999999999999999999":  "99999999999999999999",
	} {
		amount, err := ParseAmount(input)
		if err != nil {
			t.Fatalf("ParseAmount(%q): %v", input, err)
		}
		if got := amount.String(); got != expected {
			t.Fatalf("ParseAmount(%q) = %q, want %q", input, got, expected)
		}
	}
}

func TestParseAmountRejectsInvalidValues(t *testing.T) {
	for _, input := range []string{"", "+1", "01", ".1", "1.", "1e2", "1.0000000000000000001", "123456789012345678901234567890123456789"} {
		if _, err := ParseAmount(input); err == nil {
			t.Fatalf("ParseAmount(%q) succeeded", input)
		}
	}
}

func TestAmountAdditionIsExact(t *testing.T) {
	one, _ := ParseAmount("0.1")
	two, _ := ParseAmount("0.2")
	minusThree, _ := ParseAmount("-0.3")
	if got := one.Add(two).Add(minusThree); !got.IsZero() {
		t.Fatalf("expected exact zero, got %s", got.String())
	}
}