Skip to content

Instantly share code, notes, and snippets.

@zkessin
Created May 24, 2019 09:27
Show Gist options
  • Save zkessin/44ccadf1e5292d0af173f88f069dbb4a to your computer and use it in GitHub Desktop.
Save zkessin/44ccadf1e5292d0af173f88f069dbb4a to your computer and use it in GitHub Desktop.
defmodule CounterTest do
use ExUnit.Case
use PropCheck.StateM
use PropCheck
require Logger
test "Start" do
{:ok, pid} = Counter.start_link(0)
assert Process.alive?(pid)
Counter.stop()
assert(!Process.alive?(pid))
end
@moduletag timeout: :infinity
property "Server count is correct" do
forall cmds in non_empty(commands(__MODULE__)) do
trap_exit do
{:ok, pid} = Counter.start_link(0)
assert Process.alive?(pid)
r = run_commands(__MODULE__, cmds)
{history, state, result} = r
Counter.stop()
(result == :ok)
|> when_fail(
IO.puts("""
History: #{inspect(history, pretty: true)}
State: #{inspect(state, pretty: true)}
Result: #{inspect(result, pretty: true)}
""")
)
|> aggregate(command_names(cmds))
end
end
end
def initial_state() do
%{count: 0, watches: []}
end
def command(_state) do
oneof([
{:call, Counter, :increment, []},
{:call, Counter, :decrement, []},
{:call, Counter, :watch, [integer(-5, 5)]}
])
end
def next_state(state = %{count: val}, _value, {:call, Counter, :increment, []}) do
%{state | count: val + 1}
end
def next_state(state = %{count: val}, _value, {:call, Counter, :decrement, []}) do
%{state | count: val - 1}
end
def next_state(
state = %{watches: watches},
_value,
{:call, Counter, :watch, [value]}
) do
%{state | watches: [value | watches]}
end
def precondition(_state, _call) do
true
end
def postcondition(%{count: count, watches: watches}, {:call, Counter, :increment, []}, :ok) do
watch(count + 1, watches)
Counter.value() == count + 1
end
def postcondition(%{count: count, watches: watches}, {:call, Counter, :decrement, []}, :ok) do
watch(count - 1, watches)
Counter.value() == count - 1
end
def postcondition(_state, {:call, Counter, :watch, [_value]}, :ok) do
true
end
#################################################################################
def watch(_count, []) do
:ok
end
def watch(count, [count | rest]) do
receive do
{:alarm, count} -> watch(count, rest)
after
50 -> raise("no_alarm")
end
end
def watch(count, [_other | rest]) do
watch(count, rest)
end
end
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment