1 files changed, 60 insertions, 1 deletions
diff --git a/lib/kernel/test/logger_formatter_SUITE.erl b/lib/kernel/test/logger_formatter_SUITE.erl
index c171165944..934fe4deef 100644
--- a/lib/kernel/test/logger_formatter_SUITE.erl
+++ b/lib/kernel/test/logger_formatter_SUITE.erl
@@ -68,7 +68,8 @@ all() ->
      level_or_msg_in_meta,
      faulty_log,
      faulty_config,
-     faulty_msg].
+     faulty_msg,
+     update_config].
 
 default(_Config) ->
     String1 = format(info,{"~p",[term]},#{},#{}),
@@ -532,6 +533,54 @@ faulty_msg(_Config) ->
                                      #{})),
     ok.
 
+%% Test that formatter config can be changed, and that the default
+%% template is updated accordingly
+update_config(_Config) ->
+    logger:add_handler_filter(default,silence,{fun(_,_) -> stop end,ok}),
+    ok = logger:add_handler(?MODULE,?MODULE,#{}),
+    D = lists:seq(1,1000),
+    logger:info("~p~n",[D]),
+    {Lines1,C1} = check_log(),
+    [ct:log(L) || L <- Lines1],
+    ct:log("~p",[C1]),
+    [Line1] = Lines1,
+    [_Time,"info: "++D1] = string:split(Line1," "),
+    true = length(D1)>3000,
+    true = #{}==C1,
+
+    ok = logger:update_formatter_config(?MODULE,single_line,false),
+    logger:info("~p~n",[D]),
+    {Lines2,C2} = check_log(),
+    [ct:log(L) || L <- Lines2],
+    ct:log("~p",[C2]),
+    true = length(Lines2)>50,
+    true = #{single_line=>false}==C2,
+
+    ok = logger:update_formatter_config(?MODULE,#{legacy_header=>true}),
+    logger:info("~p~n",[D]),
+    {Lines3,C3} = check_log(),
+    [ct:log(L) || L <- Lines3],
+    ct:log("~p",[C3]),
+    ["=INFO REPORT==== "++_|D3] = Lines3,
+    true = length(D3)>50,
+    true = #{legacy_header=>true,single_line=>false}==C3,
+
+    ok = logger:update_formatter_config(?MODULE,single_line,true),
+    logger:info("~p~n",[D]),
+    {Lines4,C4} = check_log(),
+    [ct:log(L) || L <- Lines4],
+    ct:log("~p",[C4]),
+    ["=INFO REPORT==== "++_,D4] = Lines4,
+    true = length(D4)>3000,
+    true = #{legacy_header=>true,single_line=>true}==C4,
+
+    ok.
+
+update_config(cleanup,_Config) ->
+    _ = logger:remove_handler(?MODULE),
+    _ = logger:remove_handler_filter(default,silence),
+    ok.
+
 %%%-----------------------------------------------------------------
 %%% Internal
 format(Level,Msg,Meta,Config) ->
@@ -575,3 +624,13 @@ add_time(#{time:=_}=Meta) ->
     Meta;
 add_time(Meta) ->
     Meta#{time=>timestamp()}.
+
+%%%-----------------------------------------------------------------
+%%% handler callback
+log(Log,#{formatter:={M,C}}) ->
+    put(log,{M:format(Log,C),C}),
+    ok.
+
+check_log() ->
+    {S,C} = erase(log),
+    {string:lexemes(S,"\n"),C}.