this repo has no description
Add BTree model fuzzer
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+97
lib/btree/fuzz/model_fuzz.ex
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lib/btree/fuzz/model_fuzz.ex
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defmodule Hobbes.BTree.Fuzz.ModelFuzz do
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alias Hobbes.BTree
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import Hobbes.FuzzUtils
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defmodule State do
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@enforce_keys [
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:btree,
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:opts,
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]
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defstruct @enforce_keys
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end
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def run(seed, opts) do
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:rand.seed(:exsss, seed)
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opts = validate_opts(opts, [
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:iterations,
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:key_bits,
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batch_size_range: 1..100,
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btree_opts: [],
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seed: seed,
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])
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:ok = fuzz(opts)
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:ok
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end
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defp fuzz(opts) do
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state = %State{
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btree: BTree.new(opts.btree_opts),
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opts: opts,
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}
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Enum.reduce(1..opts.iterations, state, fn iteration, state ->
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try do
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fuzz_iteration(state)
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rescue e in [ExUnit.AssertionError] ->
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e = Map.update!(e, :message, &(&1 <> " (at seed=#{opts.seed}, iteration=#{inspect(iteration)})"))
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reraise e, __STACKTRACE__
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end
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end)
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:ok
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end
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defp fuzz_iteration(%State{} = state) do
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op = random_op()
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execute(op, state)
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end
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defp random_op do
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case Enum.random(1..1) do
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1 -> :apply_batch
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end
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end
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defp execute(:apply_batch, %State{} = state) do
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%{
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btree: btree,
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opts: opts,
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} = state
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mutations = make_batch(opts)
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:ok = BTree.Writer.apply_batch(btree, mutations)
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state
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end
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defp make_batch(opts) do
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opt_key_bits = opts.key_bits
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batch_size = Enum.random(opts.batch_size_range)
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do_make_batch(opt_key_bits, [], batch_size)
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end
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defp do_make_batch(_opt_key_bits, acc, 0), do: acc
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defp do_make_batch(opt_key_bits, acc, count) do
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acc = [make_mutation(opt_key_bits) | acc]
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count = count - 1
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do_make_batch(opt_key_bits, acc, count)
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end
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defp make_mutation(opt_key_bits) do
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case Enum.random(1..1) do
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1 ->
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key = make_key(opt_key_bits)
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value = String.duplicate(String.reverse(key), 2)
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{:write, key, value}
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end
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end
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defp make_key(bits) do
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:rand.uniform((2 ** bits) - 1)
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|> :binary.encode_unsigned()
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|> Base.encode16(case: :lower)
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end
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end
+14
lib/fuzz_utils.ex
+14
lib/fuzz_utils.ex
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defmodule Hobbes.FuzzUtils do
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@spec validate_opts(keyword, [atom | {atom, term}]) :: map
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def validate_opts(opts, expected) do
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Map.new(expected, fn
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{key, default} ->
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{key, Keyword.get(opts, key, default)}
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key ->
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case Keyword.fetch(opts, key) do
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{:ok, value} -> {key, value}
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:error -> raise "Key #{inspect(key)} was not found in #{inspect(opts)}"
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end
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end)
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end
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end
+14
test/btree_test.exs
+14
test/btree_test.exs
···
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@moduletag :btree
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defmodule ModelFuzzTest do
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use ExUnit.Case, async: true
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@moduletag :btree
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@moduletag :btree_fuzz
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@moduletag :btree_model
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test "fuzz" do
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Hobbes.BTree.Fuzz.ModelFuzz.run(100, [
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iterations: 100,
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key_bits: 32,
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])
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end
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end
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describe "BTree" do
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test "insert" do
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btree = BTree.new()