var emptySum = PackPallocSum(PallocChunkPages, PallocChunkPages, PallocChunkPages)
	type test struct {
		free []BitRange // Ranges of free (zero) bits.
		hits []PallocSum
	}
	tests := make(map[string]test)
	tests["NoneFree"] = test{
		free: []BitRange{},
		hits: []PallocSum{
			PackPallocSum(0, 0, 0),
		},
	}
	tests["OnlyStart"] = test{
		free: []BitRange{{0, 10}},
		hits: []PallocSum{
			PackPallocSum(10, 10, 0),

		}
		tests["AllScavenged"+suffix] = test{
			scavenged: []BitRange{{0, PallocChunkPages}},
			min:       m,
			max:       PallocChunkPages,
			want:      BitRange{0, 0},
		}
		tests["NoneFree"+suffix] = test{
			alloc:     []BitRange{{0, PallocChunkPages}},
			scavenged: []BitRange{{PallocChunkPages / 2, PallocChunkPages / 2}},
			min:       m,
			max:       PallocChunkPages,
			want:      BitRange{0, 0},