package partition

import "testing"

func TestFreeBytesReturnsNonZeroOnTempDir(t *testing.T) {
	b, err := FreeBytes(t.TempDir())
	if err != nil {
		t.Fatalf("FreeBytes: %v", err)
	}
	// On any sane test runner the temp filesystem has more than 1 KiB free.
	if b < 1024 {
		t.Errorf("FreeBytes = %d, want > 1024 on /tmp", b)
	}
}

func TestFreeBytesNonExistentPath(t *testing.T) {
	_, err := FreeBytes("/this/path/does/not/exist/at/all")
	if err == nil {
		t.Error("expected error for missing path, got nil")
	}
}

func TestHasFreeSpaceForRejectsHugeRequest(t *testing.T) {
	// Request 1 PiB with 10% headroom on /tmp — no test runner has that
	// much free, so this should consistently report not-enough.
	avail, ok, err := HasFreeSpaceFor(t.TempDir(), 1<<50, 10)
	if err != nil {
		t.Fatalf("HasFreeSpaceFor: %v", err)
	}
	if ok {
		t.Errorf("expected insufficient space for 1PiB, got avail=%d ok=true", avail)
	}
}

func TestHasFreeSpaceForAcceptsSmallRequest(t *testing.T) {
	// 1 KiB with 10% headroom = 1.1 KiB. Any temp dir has this.
	_, ok, err := HasFreeSpaceFor(t.TempDir(), 1024, 10)
	if err != nil {
		t.Fatalf("HasFreeSpaceFor: %v", err)
	}
	if !ok {
		t.Error("expected sufficient space for 1KiB on /tmp")
	}
}