server: fix artifact handling reset on restart

Fix a bug when server initialization didn't reset artifact handling,
which caused stale artifacts to persist after server restarts.

Closes #409

Author: mandesero

CHANGELOG.md

@@ -2,6 +2,8 @@
 
 ## Unreleased
 
+- Fixed a bug when server initialization didn't reset artifact handling,
+  causing stale artifacts to persist after server restarts (gh-409).
 - Group and suite hooks must now be registered using the call-style
   API. Use:
 

luatest/server.lua

@@ -327,6 +327,7 @@ function Server:initialize()
 
     local prefix = fio.pathjoin(Server.vardir, 'artifacts', self.rs_id or '')
     self.artifacts = fio.pathjoin(prefix, self.id)
+    self.artifacts_saved = false
 
     self.log_file = fio.pathjoin(self.workdir, self.alias .. '.log')
 end
@@ -585,12 +586,12 @@ function Server:stop()
     end
 end
 
---- Stop the server and save its artifacts if the test fails.
+--- Stop the server and save its artifacts.
 -- This function should be used only at the end of the test (`after_test`,
 -- `after_each`, `after_all` hooks) to terminate the server process.
 -- Besides process termination, it saves the contents of the server
 -- working directory to the `<vardir>/artifacts` directory for further
--- analysis if the test fails.
+-- analysis.
 function Server:drop()
     self:stop()
     self:save_artifacts()

test/server_test.lua

@@ -645,3 +645,28 @@ g.test_assertion_failure = function()
     server:connect_net_box()
     helper.assert_failure(server.exec, server, function() t.assert(false) end)
 end
+
+g.test_save_artifacts_after_restart_when_test_failed = function()
+    local s = Server:new()
+
+    s:start()
+    s:exec(function()
+        require('log').info('before_restart_artifacts_marker')
+    end)
+
+    s:restart()
+    s:exec(function()
+        require('log').info('after_restart_artifacts_marker')
+    end)
+
+    s:drop()
+
+    local log_path = fio.pathjoin(s.artifacts, s.alias .. '.log')
+    local log_file = fio.open(log_path)
+    local log_stat = log_file:stat()
+    local log_content = log_file:read(log_stat.size)
+    log_file:close()
+
+    t.assert_str_contains(log_content, 'before_restart_artifacts_marker')
+    t.assert_str_contains(log_content, 'after_restart_artifacts_marker')
+end