Fixes a race condition found in percept_db start/1 function.

When function start/1 finds an instance of percept_db running, it will send a message to stop it and spawn a process to start a new one, which leads to a race condition.
The function will return {restarted, pid()} but the pid() will die once it tries to create the ets table.

1 files changed, 76 insertions, 0 deletions

diff --git a/lib/percept/test/percept_db_SUITE.erl b/lib/percept/test/percept_db_SUITE.erl
new file mode 100644
index 0000000000..79be9714ba
--- /dev/null
+++ b/lib/percept/test/percept_db_SUITE.erl
@@ -0,0 +1,76 @@
+%%
+%% %CopyrightBegin%
+%%
+%% Copyright Ericsson AB 2007-2010. All Rights Reserved.
+%%
+%% The contents of this file are subject to the Erlang Public License,
+%% Version 1.1, (the "License"); you may not use this file except in
+%% compliance with the License. You should have received a copy of the
+%% Erlang Public License along with this software. If not, it can be
+%% retrieved online at http://www.erlang.org/.
+%%
+%% Software distributed under the License is distributed on an "AS IS"
+%% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
+%% the License for the specific language governing rights and limitations
+%% under the License.
+%%
+%% %CopyrightEnd%
+%%
+
+-module(percept_db_SUITE).
+-include("test_server.hrl").
+
+%% Test server specific exports
+-export([all/1]).
+-export([init_per_suite/1, end_per_suite/1]).
+-export([init_per_testcase/2, end_per_testcase/2]).
+
+%% Test cases
+-export([
+	start/1
+	]).
+
+%% Default timetrap timeout (set in init_per_testcase)
+-define(default_timeout, ?t:minutes(2)).
+-define(restarts, 10).
+-define(alive_timeout, 500).
+
+init_per_suite(Config) when is_list(Config) ->
+    Config.
+
+end_per_suite(Config) when is_list(Config) ->
+    Config.
+
+init_per_testcase(_Case, Config) ->
+    Dog = ?t:timetrap(?default_timeout),
+    [{max_size, 300}, {watchdog,Dog} | Config].
+
+end_per_testcase(_Case, Config) ->
+    Dog = ?config(watchdog, Config),
+    ?t:timetrap_cancel(Dog),
+    ok.
+
+all(suite) ->
+    % Test cases
+    [start].
+
+%%----------------------------------------------------------------------
+%% Tests
+%%----------------------------------------------------------------------
+
+start(suite) ->
+    [];
+start(doc) ->
+    ["Percept_db start and restart test."];
+start(Config) when is_list(Config) ->
+    ok = restart(?restarts),
+    {stopped, _DB} = percept_db:stop(),
+    ok.
+
+restart(0)->
+    ok;
+restart(N)->
+    {_, DB} = percept_db:start(),
+    timer:sleep(?alive_timeout),
+    true = erlang:is_process_alive(DB),
+    restart(N-1).