Merge branch 'zandra/common_test/unmatched_returns/OTP-13345'

* zandra/common_test/unmatched_returns/OTP-13345: (23 commits)
  ct logs: Fix unmatched_return warnings
  ct_util: Fix unmatched_return warnings
  erl2html2: Fix unmatched_return warnings
  cth_conn_log: Fix unmatched_return warnings
  ct_webtool: Fix unmatched_return warnings
  ct_telnet: Fix unmatched_return warnings
  ct_ssh: Fix unmatched_return warnings
  ct_snmp: Fix unmatched_return warnings
  ct_slave: Fix unmatched_return warnings
  ct_rpc: Fix unmatched_return warnings
  ct_repeat: Fix unmatched_return warnings
  ct_release_test: Fix unmatched_return warnings
  ct_property_test: Fix unmatched_return warnings
  ct_master: Fix unmatched_return warnings
  ct_hooks_lock: Fix unmatched_return warnings
  ct_hooks: Fix unmatched_return warnings
  ct_groups: Fix unmatched_return warnings
  ct_ftp: Fix unmatched_return warnings
  ct_framework: Fix unmatched_return warnings
  ct_config: Fix unmatched_return warnings
  ...

26 files changed, 346 insertions, 220 deletions

diff --git a/lib/common_test/src/ct.erl b/lib/common_test/src/ct.erl
index cae7bea406..d7ae81a5ce 100644
--- a/lib/common_test/src/ct.erl
+++ b/lib/common_test/src/ct.erl
@@ -282,7 +282,7 @@ step(TestDir,Suite,Case,Opts) ->
 %%% <c>&gt; ct_telnet:cmd(unix_telnet, "ls .").</c><br/>
 %%% <c>{ok,["ls","file1  ...",...]}</c></p>
 start_interactive() ->
-    ct_util:start(interactive),
+    _ = ct_util:start(interactive),
     ok.
 
 %%%-----------------------------------------------------------------
diff --git a/lib/common_test/src/ct_config.erl b/lib/common_test/src/ct_config.erl
index b499bc8b05..99de311570 100644
--- a/lib/common_test/src/ct_config.erl
+++ b/lib/common_test/src/ct_config.erl
@@ -119,7 +119,8 @@ call(Msg) ->
     end.
 
 return({To,Ref},Result) ->
-    To ! {Ref, Result}.
+    To ! {Ref, Result},
+    ok.
 
 loop(StartDir) ->
     receive
@@ -128,11 +129,11 @@ loop(StartDir) ->
 	    return(From,Result),
 	    loop(StartDir);
 	{{set_default_config,{Config,Scope}},From} ->
-	    set_config(Config,{true,Scope}),
+	    _ = set_config(Config,{true,Scope}),
 	    return(From,ok),
 	    loop(StartDir);
 	{{set_default_config,{Name,Config,Scope}},From} ->
-	    set_config(Name,Config,{true,Scope}),
+	    _ = set_config(Name,Config,{true,Scope}),
 	    return(From,ok),
 	    loop(StartDir);
 	{{delete_default_config,Scope},From} ->
@@ -149,7 +150,7 @@ loop(StartDir) ->
 	    loop(StartDir);
 	{{stop},From} ->
 	    ets:delete(?attr_table),
-	    file:set_cwd(StartDir),
+	    ok = file:set_cwd(StartDir),
 	    return(From,ok)
     end.
 
@@ -257,7 +258,7 @@ read_config_files(Opts) ->
 read_config_files_int([{Callback, File}|Files], FunToSave) ->
     case Callback:read_config(File) of
 	{ok, Config} ->
-	    FunToSave(Config, Callback, File),
+	    _ = FunToSave(Config, Callback, File),
 	    read_config_files_int(Files, FunToSave);
 	{error, {ErrorName, ErrorDetail}} ->
 	    {user_error, {ErrorName, File, ErrorDetail}};
@@ -267,6 +268,15 @@ read_config_files_int([{Callback, File}|Files], FunToSave) ->
 read_config_files_int([], _FunToSave) ->
     ok.
 
+
+read_config_files(ConfigFiles, FunToSave) ->
+    case read_config_files_int(ConfigFiles, FunToSave) of
+        {user_error, Error} ->
+            {error, Error};
+        ok ->
+            ok
+    end.
+
 store_config(Config, Callback, File) when is_tuple(Config) ->
     store_config([Config], Callback, File);
 
@@ -455,8 +465,12 @@ reload_conf(KeyOrName) ->
 	    undefined;
 	HandlerList ->
 	    HandlerList2 = lists:usort(HandlerList),
-	    read_config_files_int(HandlerList2, fun rewrite_config/3),
-	    get_config(KeyOrName)
+	    case read_config_files(HandlerList2, fun rewrite_config/3) of
+		ok ->
+		    get_config(KeyOrName);
+		Error ->
+		    Error
+	    end
     end.
 
 release_allocated() ->
@@ -490,16 +504,16 @@ associate(Name,_Key,Configs) ->
     associate_int(Name,Configs,os:getenv("COMMON_TEST_ALIAS_TOP")).
 
 associate_int(Name,Configs,"true") ->
-    lists:map(fun({K,_Config}) ->
+    lists:foreach(fun({K,_Config}) ->
 		      Cs = ets:match_object(
 			     ?attr_table,
 			     #ct_conf{key=element(1,K),
 				      name='_UNDEF',_='_'}),
 		      [ets:insert(?attr_table,C#ct_conf{name=Name})
 		       || C <- Cs]
-	      end,Configs);
+		  end,Configs);
 associate_int(Name,Configs,_) ->
-    lists:map(fun({K,Config}) ->
+    lists:foreach(fun({K,Config}) ->
 		      Key = if is_tuple(K) -> element(1,K);
 			       is_atom(K) -> K
 			    end,
@@ -511,7 +525,7 @@ associate_int(Name,Configs,_) ->
 		      [ets:insert(?attr_table,C#ct_conf{name=Name,
 							value=Config})
 		       || C <- Cs]
-	      end,Configs).
+		  end,Configs).
 
 
 
@@ -576,7 +590,7 @@ encrypt_config_file(SrcFileName, EncryptFileName, {file,KeyFile}) ->
     end;
 
 encrypt_config_file(SrcFileName, EncryptFileName, {key,Key}) ->
-    crypto:start(),
+    _ = crypto:start(),
     {Key,IVec} = make_crypto_key(Key),
     case file:read_file(SrcFileName) of
 	{ok,Bin0} ->
@@ -615,7 +629,7 @@ decrypt_config_file(EncryptFileName, TargetFileName, {file,KeyFile}) ->
     end;
 
 decrypt_config_file(EncryptFileName, TargetFileName, {key,Key}) ->
-    crypto:start(),
+    _ = crypto:start(),
     {Key,IVec} = make_crypto_key(Key),
     case file:read_file(EncryptFileName) of
 	{ok,Bin} ->
@@ -778,14 +792,13 @@ prepare_config_list(Args) ->
 
 % TODO: add logging of the loaded configuration file to the CT FW log!!!
 add_config(Callback, []) ->
-    read_config_files_int([{Callback, []}], fun store_config/3);
+    read_config_files([{Callback, []}], fun store_config/3);
 add_config(Callback, [File|_Files]=Config) when is_list(File) ->
     lists:foreach(fun(CfgStr) ->
-	read_config_files_int([{Callback, CfgStr}], fun store_config/3) end,
+	read_config_files([{Callback, CfgStr}], fun store_config/3) end,
 	Config);
 add_config(Callback, [C|_]=Config) when is_integer(C) ->
-    read_config_files_int([{Callback, Config}], fun store_config/3),
-    ok.
+    read_config_files([{Callback, Config}], fun store_config/3).
 
 remove_config(Callback, Config) ->
     ets:match_delete(?attr_table,
diff --git a/lib/common_test/src/ct_framework.erl b/lib/common_test/src/ct_framework.erl
index eb32f7f3fc..104515e57e 100644
--- a/lib/common_test/src/ct_framework.erl
+++ b/lib/common_test/src/ct_framework.erl
@@ -128,7 +128,7 @@ init_tc1(?MODULE,_,error_in_suite,_,[Config0]) when is_list(Config0) ->
     ct_event:notify(#event{name=tc_start,
 			   node=node(),
 			   data={?MODULE,error_in_suite}}),
-    ct_suite_init(?MODULE,error_in_suite,[],Config0),
+    _ = ct_suite_init(?MODULE,error_in_suite,[],Config0),
     case ?val(error,Config0) of
 	undefined ->
 	    {fail,"unknown_error_in_suite"};
@@ -212,7 +212,7 @@ init_tc2(Mod,Suite,Func,HookFunc,SuiteInfo,MergeResult,Config) ->
     %% timetrap must be handled before require
     MergedInfo = timetrap_first(MergeResult, [], []),
     %% tell logger to use specified style sheet
-    case lists:keysearch(stylesheet,1,MergeResult++Config) of
+    _ = case lists:keysearch(stylesheet,1,MergeResult++Config) of
 	{value,{stylesheet,SSFile}} ->
 	    ct_logs:set_stylesheet(Func,add_data_dir(SSFile,Config));
 	_ ->
@@ -632,10 +632,10 @@ try_set_default(Name,Key,Info,Where) ->
 	{_,[]} -> 
 	    no_default;
 	{'_UNDEF',_} ->
-	    [ct_config:set_default_config([CfgVal],Where) || CfgVal <- CfgElems],
+	    _ = [ct_config:set_default_config([CfgVal],Where) || CfgVal <- CfgElems],
 	    ok;
 	_ ->
-	    [ct_config:set_default_config(Name,[CfgVal],Where) || CfgVal <- CfgElems],
+	    _ = [ct_config:set_default_config(Name,[CfgVal],Where) || CfgVal <- CfgElems],
 	    ok
     end.
 	    
@@ -1315,7 +1315,7 @@ report(What,Data) ->
 	    %% top level test index page needs to be refreshed
 	    TestName = filename:basename(?val(topdir, Data), ".logs"),
 	    RunDir = ?val(rundir, Data),
-	    ct_logs:make_all_suites_index({TestName,RunDir}),
+	    _ = ct_logs:make_all_suites_index({TestName,RunDir}),
 	    ok;
 	tests_start ->
 	    ok;
diff --git a/lib/common_test/src/ct_ftp.erl b/lib/common_test/src/ct_ftp.erl
index 48914864e4..84e664b387 100644
--- a/lib/common_test/src/ct_ftp.erl
+++ b/lib/common_test/src/ct_ftp.erl
@@ -292,7 +292,7 @@ init(KeyOrName,{IP,Port},{Username,Password}) ->
     end.
 	    
 ftp_connect(IP,Port,Username,Password) ->
-    inets:start(),
+    _ = inets:start(),
     case inets:start(ftpc,[{host,IP},{port,Port}]) of
 	{ok,FtpPid} ->
 	    case ftp:user(FtpPid,Username,Password) of
diff --git a/lib/common_test/src/ct_groups.erl b/lib/common_test/src/ct_groups.erl
index dd04c5410a..1375e7dcc7 100644
--- a/lib/common_test/src/ct_groups.erl
+++ b/lib/common_test/src/ct_groups.erl
@@ -402,12 +402,7 @@ expand(Mod, Name, Defs) ->
     end.
 
 make_all_conf(Dir, Mod, Props, TestSpec) ->
-    case code:is_loaded(Mod) of
-	false ->
-	    code:load_abs(filename:join(Dir,atom_to_list(Mod)));
-	_ ->
-	    ok
-    end,
+    _ = load_abs(Dir, Mod),
     make_all_conf(Mod, Props, TestSpec).
 
 make_all_conf(Mod, Props, TestSpec) ->
@@ -428,16 +423,19 @@ make_all_conf(Mod, Props, TestSpec) ->
     end.
 
 make_conf(Dir, Mod, Name, Props, TestSpec) ->
+    _ = load_abs(Dir, Mod),
+    make_conf(Mod, Name, Props, TestSpec).
+
+load_abs(Dir, Mod) ->
     case code:is_loaded(Mod) of
 	false ->
 	    code:load_abs(filename:join(Dir,atom_to_list(Mod)));
 	_ ->
 	    ok
-    end,
-    make_conf(Mod, Name, Props, TestSpec).
+    end.
 
 make_conf(Mod, Name, Props, TestSpec) ->
-    case code:is_loaded(Mod) of
+    _ = case code:is_loaded(Mod) of
 	false ->
 	    code:load_file(Mod);
 	_ ->
diff --git a/lib/common_test/src/ct_hooks.erl b/lib/common_test/src/ct_hooks.erl
index 5422d449fd..c9a4abb5ee 100644
--- a/lib/common_test/src/ct_hooks.erl
+++ b/lib/common_test/src/ct_hooks.erl
@@ -408,7 +408,8 @@ catch_apply(M,F,A, Default) ->
 maybe_start_locker(Mod,GroupName,Opts) ->
     case lists:member(parallel,Opts) of
 	true ->
-	    {ok, _Pid} = ct_hooks_lock:start({Mod,GroupName});
+	    {ok, _Pid} = ct_hooks_lock:start({Mod,GroupName}),
+	    ok;
 	false ->
 	    ok
     end.
diff --git a/lib/common_test/src/ct_hooks_lock.erl b/lib/common_test/src/ct_hooks_lock.erl
index f41f259f7b..fea298e535 100644
--- a/lib/common_test/src/ct_hooks_lock.erl
+++ b/lib/common_test/src/ct_hooks_lock.erl
@@ -82,7 +82,7 @@ init(Id) ->
 
 %% @doc Handling call messages
 handle_call({stop,Id}, _From, #state{ id = Id, requests = Reqs } = State) ->
-    [gen_server:reply(Req, locker_stopped) || {Req,_ReqId} <- Reqs],
+    _ = [gen_server:reply(Req, locker_stopped) || {Req,_ReqId} <- Reqs],
     {stop, normal, stopped, State};
 handle_call({stop,_Id}, _From, State) ->
     {reply, stopped, State};
diff --git a/lib/common_test/src/ct_logs.erl b/lib/common_test/src/ct_logs.erl
index e6d683c8a9..455864efb6 100644
--- a/lib/common_test/src/ct_logs.erl
+++ b/lib/common_test/src/ct_logs.erl
@@ -149,7 +149,7 @@ close(Info, StartDir) ->
 				 ok;
 			     CacheBin ->
 				 %% save final version of the log cache to file
-				 file:write_file(?log_cache_name,CacheBin),
+				 _ = file:write_file(?log_cache_name,CacheBin),
 				 put(ct_log_cache,undefined)
 			 end
 		 end,
@@ -175,12 +175,12 @@ close(Info, StartDir) ->
 		Error ->
 		    io:format("Warning! Cleanup failed: ~p~n", [Error])
 	    end,
-	    make_all_suites_index(stop),
+	    _ = make_all_suites_index(stop),
 	    make_all_runs_index(stop),
 	    Cache2File();
        true -> 
-	    file:set_cwd(".."),
-	    make_all_suites_index(stop),
+	    ok = file:set_cwd(".."),
+	    _ = make_all_suites_index(stop),
 	    make_all_runs_index(stop),
 	    Cache2File(),
 	    case ct_util:get_profile_data(browser, StartDir) of
@@ -251,16 +251,30 @@ call(Msg) ->
     end.
 
 return({To,Ref},Result) ->
-    To ! {Ref, Result}.
+    To ! {Ref, Result},
+    ok.
 
 cast(Msg) ->
     case whereis(?MODULE) of
 	undefined ->
-	    {error,does_not_exist};
+	    io:format("Warning: ct_logs not started~n"),
+	    {_,_,_,_,_,_,Content,_} = Msg,
+	    FormatArgs = get_format_args(Content),
+	    _ = [io:format(Format, Args) || {Format, Args} <- FormatArgs],
+	    ok;
 	_Pid ->
-	    ?MODULE ! Msg
+	    ?MODULE ! Msg,
+	    ok
     end.
 
+get_format_args(Content) ->
+    lists:map(fun(C) ->
+		  case C of
+		      {_, FA, _} -> FA;
+		      {_, _} -> C
+		  end
+	      end, Content).
+
 %%%-----------------------------------------------------------------
 %%% @spec init_tc(RefreshLog) -> ok
 %%%
@@ -631,7 +645,7 @@ logger(Parent, Mode, Verbosity) ->
 	end,
     %%! <---
 
-    file:make_dir(Dir),
+    _ = file:make_dir(Dir),
     AbsDir = ?abs(Dir),
     put(ct_run_dir, AbsDir),
 
@@ -671,7 +685,7 @@ logger(Parent, Mode, Verbosity) ->
 	    end
     end,
 
-    test_server_io:start_link(),
+    _ = test_server_io:start_link(),
     MiscIoName = filename:join(Dir, ?misc_io_log),
     {ok,MiscIoFd} = file:open(MiscIoName,
 			      [write,{encoding,utf8}]),
@@ -701,13 +715,13 @@ logger(Parent, Mode, Verbosity) ->
     ct_event:notify(#event{name=start_logging,node=node(),
 			   data=AbsDir}),
     make_all_runs_index(start),
-    make_all_suites_index(start),
+    _ = make_all_suites_index(start),
     case Mode of
 	interactive -> interactive_link();
 	_ -> ok
     end,
-    file:set_cwd(Dir),
-    make_last_run_index(Time),
+    ok = file:set_cwd(Dir),
+    _ = make_last_run_index(Time),
     CtLogFd = open_ctlog(?misc_io_log),
     io:format(CtLogFd,int_header()++int_footer(),
 	      [log_timestamp(?now),"Common Test Logger started"]),
@@ -721,13 +735,13 @@ logger(Parent, Mode, Verbosity) ->
 	GenLvl    -> io:format(CtLogFd, "~-25s~3w~n",
 			       ["general level",GenLvl])
     end,
-    [begin put({verbosity,Cat},VLvl),
-	   if Cat == '$unspecified' ->
+    _ = [begin put({verbosity,Cat},VLvl),
+	     if Cat == '$unspecified' ->
 		   ok;
-	      true ->
+		true ->
 		   io:format(CtLogFd, "~-25w~3w~n", [Cat,VLvl])
-	   end
-     end || {Cat,VLvl} <- Verbosity],
+	     end
+	 end || {Cat,VLvl} <- Verbosity],
     io:nl(CtLogFd),
     TcEscChars = case application:get_env(common_test, esc_chars) of
 		   {ok,ECBool} -> ECBool;
@@ -804,7 +818,7 @@ logger_loop(State) ->
 	    print_style(GL, IoFormat, State#logger_state.stylesheet),
 	    set_evmgr_gl(GL),
 	    TCGLs = add_tc_gl(TCPid,GL,State),
-	    if not RefreshLog ->
+	    _ = if not RefreshLog ->
 		    ok;
 	       true ->
 		    make_last_run_index(State#logger_state.start_time)
@@ -831,7 +845,7 @@ logger_loop(State) ->
 	    return(From,{ok,filename:basename(State#logger_state.log_dir)}),
 	    logger_loop(State);
 	{make_last_run_index,From} ->
-	    make_last_run_index(State#logger_state.start_time),
+	    _ = make_last_run_index(State#logger_state.start_time),
 	    return(From,get(ct_log_cache)),
 	    logger_loop(State);
 	{set_stylesheet,_,SSFile} when State#logger_state.stylesheet ==
@@ -1169,7 +1183,7 @@ print_style_error(Fd, IoFormat, StyleSheet, Reason) ->
 close_ctlog(Fd) ->
     io:format(Fd, "\n</pre>\n", []),
     io:format(Fd, [xhtml("<br><br>\n", "<br /><br />\n") | footer()], []),
-    file:close(Fd).
+    ok = file:close(Fd).
 
 %%%-----------------------------------------------------------------
 %%% tc_io_format/3
@@ -1773,7 +1787,7 @@ count_cases(Dir) ->
 			    %% file yet.
 			    {0,0,0,0};
 			Summary ->
-			    write_summary(SumFile, Summary),
+			    _ = write_summary(SumFile, Summary),
 			    Summary
 		    end;
 		{error, Reason} ->
@@ -2088,7 +2102,7 @@ interactive_link() ->
 	 "</body>\n",
 	 "</html>\n"
 	],
-    file:write_file("last_interactive.html",unicode:characters_to_binary(Body)),
+    _ = file:write_file("last_interactive.html",unicode:characters_to_binary(Body)),
     io:format("~n~nUpdated ~ts\n"
 	      "Any CT activities will be logged here\n",
 	      [?abs("last_interactive.html")]).
@@ -2219,9 +2233,9 @@ runentry(Dir, _, _) ->
 write_totals_file(Name,Label,Logs,Totals) ->
     AbsName = ?abs(Name),
     notify_and_lock_file(AbsName),
-    force_write_file(AbsName,
-		     term_to_binary({atom_to_list(node()),
-				     Label,Logs,Totals})),
+    _ = force_write_file(AbsName,
+			 term_to_binary({atom_to_list(node()),
+					 Label,Logs,Totals})),
     notify_and_unlock_file(AbsName).
 
 %% this function needs to convert from old formats to new so that old
@@ -2266,7 +2280,7 @@ read_totals_file(Name) ->
     Result.
 
 force_write_file(Name,Contents) ->
-    force_delete(Name),
+    _ = force_delete(Name),
     file:write_file(Name,Contents).
 
 force_delete(Name) ->
@@ -2817,18 +2831,18 @@ get_cache_data({ok,CacheBin}) ->
 		true ->
 		    {ok,CacheRec};
 		false ->
-		    file:delete(?log_cache_name),
+		    _ = file:delete(?log_cache_name),
 		    {error,old_cache_file}
 	    end;				    
 	_ ->
-	    file:delete(?log_cache_name),
+	    _ = file:delete(?log_cache_name),
 	    {error,invalid_cache_file}
     end;
 get_cache_data(NoCache) ->
     NoCache.
 
 cache_vsn() ->
-    application:load(common_test),
+    _ = application:load(common_test),
     case application:get_key(common_test,vsn) of
 	{ok,VSN} ->
 	    VSN;
diff --git a/lib/common_test/src/ct_master.erl b/lib/common_test/src/ct_master.erl
index c4905b316f..4eef27d2a5 100644
--- a/lib/common_test/src/ct_master.erl
+++ b/lib/common_test/src/ct_master.erl
@@ -376,7 +376,7 @@ init_master(Parent,NodeOptsList,EvHandlers,MasterLogDir,LogDirs,
     end,
 
     %% start master event manager and add default handler
-    ct_master_event:start_link(),
+    {ok, _}  = start_ct_master_event(),
     ct_master_event:add_handler(),
     %% add user handlers for master event manager
     Add = fun({H,Args}) ->
@@ -398,6 +398,14 @@ init_master(Parent,NodeOptsList,EvHandlers,MasterLogDir,LogDirs,
     end,
     init_master1(Parent,NodeOptsList,InitOptions,LogDirs).
 
+start_ct_master_event() ->
+    case ct_master_event:start_link() of
+        {error, {already_started, Pid}} ->
+            {ok, Pid};
+        Else ->
+            Else
+    end.
+
 init_master1(Parent,NodeOptsList,InitOptions,LogDirs) ->
     {Inaccessible,NodeOptsList1,InitOptions1} = init_nodes(NodeOptsList,
 							   InitOptions),
@@ -658,7 +666,7 @@ refresh_logs([D|Dirs],Refreshed) ->
 		    {ok,Cwd} = file:get_cwd(),
 		    case catch ct_run:refresh_logs(D) of
 			{'EXIT',Reason} ->
-			    file:set_cwd(Cwd),
+			    ok = file:set_cwd(Cwd),
 			    refresh_logs(Dirs,[{D,{error,Reason}}|Refreshed]);
 			Result -> 
 			    refresh_logs(Dirs,[{D,Result}|Refreshed])
@@ -701,7 +709,7 @@ init_node_ctrl(MasterPid,Cookie,Opts) ->
     end,
     
     %% start a local event manager
-    ct_event:start_link(),
+    {ok, _} = start_ct_event(),
     ct_event:add_handler([{master,MasterPid}]),
 
     %% log("Running test with options: ~p~n", [Opts]),
@@ -721,6 +729,14 @@ init_node_ctrl(MasterPid,Cookie,Opts) ->
 		      "Can't report result!~n~n", [MasterNode])
     end.
 
+start_ct_event() ->
+    case ct_event:start_link() of
+        {error, {already_started, Pid}} ->
+            {ok, Pid};
+        Else ->
+            Else
+    end.
+
 %%%-----------------------------------------------------------------
 %%% Event handling
 %%%-----------------------------------------------------------------
@@ -778,7 +794,7 @@ reply(Result,To) ->
     ok.
 
 init_nodes(NodeOptions, InitOptions)->
-    ping_nodes(NodeOptions),
+    _ = ping_nodes(NodeOptions),
     start_nodes(InitOptions),
     eval_on_nodes(InitOptions),
     {Inaccessible, NodeOptions1}=ping_nodes(NodeOptions),
diff --git a/lib/common_test/src/ct_master_logs.erl b/lib/common_test/src/ct_master_logs.erl
index 39f87a7f09..a2542171f8 100644
--- a/lib/common_test/src/ct_master_logs.erl
+++ b/lib/common_test/src/ct_master_logs.erl
@@ -91,8 +91,8 @@ init(Parent,LogDir,Nodes) ->
     Time = calendar:local_time(),
     RunDir = make_dirname(Time),
     RunDirAbs = filename:join(LogDir,RunDir),
-    file:make_dir(RunDirAbs),
-    write_details_file(RunDirAbs,{node(),Nodes}),
+    ok = make_dir(RunDirAbs),
+    _ = write_details_file(RunDirAbs,{node(),Nodes}),
 
     case basic_html() of
 	true ->
@@ -128,7 +128,7 @@ init(Parent,LogDir,Nodes) ->
 	    end
     end,
 
-    make_all_runs_index(LogDir),
+    _ = make_all_runs_index(LogDir),
     CtLogFd = open_ct_master_log(RunDirAbs),
     NodeStr = 
 	lists:flatten(lists:map(fun(N) ->
@@ -181,7 +181,7 @@ loop(State) ->
 	    lists:foreach(Fun,List),
 	    loop(State);
 	{make_all_runs_index,From} ->
-	    make_all_runs_index(State#state.logdir),
+	    _ = make_all_runs_index(State#state.logdir),
 	    return(From,State#state.logdir),
 	    loop(State);	
 	{{nodedir,Node,RunDir},From} ->
@@ -189,12 +189,12 @@ loop(State) ->
 	    return(From,ok),
 	    loop(State);	
 	stop ->
-	    make_all_runs_index(State#state.logdir),
+	    _ = make_all_runs_index(State#state.logdir),
 	    io:format(State#state.log_fd,
 		      int_header()++int_footer(),
 		      [log_timestamp(?now),"Finished!"]),
-	    close_ct_master_log(State#state.log_fd),
-	    close_nodedir_index(State#state.nodedir_ix_fd),
+	    _ = close_ct_master_log(State#state.log_fd),
+	    _ = close_nodedir_index(State#state.nodedir_ix_fd),
 	    ok
     end.
 
@@ -496,7 +496,7 @@ make_relative(Dir) ->
     ct_logs:make_relative(Dir).
 
 force_write_file(Name,Contents) ->
-    force_delete(Name),
+    _ = force_delete(Name),
     file:write_file(Name,Contents).
 
 force_delete(Name) ->
@@ -534,13 +534,34 @@ call(Msg) ->
     end.
 
 return({To,Ref},Result) ->
-    To ! {Ref, Result}.
+    To ! {Ref, Result},
+    ok.
 
 cast(Msg) ->
     case whereis(?MODULE) of
 	undefined ->
-	    {error,does_not_exist};
+	    io:format("Warning: ct_master_logs not started~n"),
+	    {_,_,Content} = Msg,
+	    FormatArgs = get_format_args(Content),
+	    _ = [io:format(Format, Args) || {Format, Args} <- FormatArgs],
+	    ok;
 	_Pid ->
-	    ?MODULE ! Msg
+	    ?MODULE ! Msg,
+	    ok
     end.
 
+get_format_args(Content) ->
+    lists:map(fun(C) ->
+		  case C of
+		      {_, FA, _} -> FA;
+		      _ -> C
+		  end
+	      end, Content).
+
+make_dir(Dir) ->
+    case file:make_dir(Dir) of
+	{error, exist} ->
+		ok;
+	    Else ->
+		Else
+    end.
diff --git a/lib/common_test/src/ct_property_test.erl b/lib/common_test/src/ct_property_test.erl
index 7dc78e949a..12c3d726d3 100644
--- a/lib/common_test/src/ct_property_test.erl
+++ b/lib/common_test/src/ct_property_test.erl
@@ -161,7 +161,9 @@ property_tests_path(Dir, Config) ->
 add_code_pathz(Dir) ->
     case lists:member(Dir, code:get_path()) of
 	true ->  ok;
-	false -> code:add_pathz(Dir)
+	false ->
+	    true = code:add_pathz(Dir),
+	    ok
     end.
 
 compile_tests(Path, ToolModule) ->
@@ -171,10 +173,10 @@ compile_tests(Path, ToolModule) ->
     {ok,FileNames} = file:list_dir("."),
     BeamFiles = [F || F<-FileNames,
 		      filename:extension(F) == ".beam"],
-    [file:delete(F) || F<-BeamFiles],
+    _ = [file:delete(F) || F<-BeamFiles],
     ct:pal("Compiling in ~p:~n  Deleted ~p~n  MacroDefs=~p",[Path,BeamFiles,MacroDefs]),
     Result = make:all([load|MacroDefs]),
-    file:set_cwd(Cwd),
+    ok = file:set_cwd(Cwd),
     Result.
     
 
diff --git a/lib/common_test/src/ct_release_test.erl b/lib/common_test/src/ct_release_test.erl
index 4e0f88cf5f..d783f8d04e 100644
--- a/lib/common_test/src/ct_release_test.erl
+++ b/lib/common_test/src/ct_release_test.erl
@@ -342,7 +342,7 @@ cleanup(Config) ->
 				 end
 			 end,
 			 AllNodes),
-    [rpc:call(Node,erlang,halt,[]) || Node <- Nodes],
+    _ = [rpc:call(Node,erlang,halt,[]) || Node <- Nodes],
     Config.
 
 %%-----------------------------------------------------------------
@@ -552,14 +552,14 @@ target_system(Apps,CreateDir,InstallDir,{FromVsn,_,AllAppsVsns,Path}) ->
 
     %% Add bin and log dirs
     BinDir = filename:join([InstallDir, "bin"]),
-    file:make_dir(BinDir),
-    file:make_dir(filename:join(InstallDir,"log")),
+    ok = make_dir(BinDir),
+    ok = make_dir(filename:join(InstallDir,"log")),
 
     %% Delete start scripts - they will be added later
     ErtsBinDir = filename:join([InstallDir, "erts-" ++ ErtsVsn, "bin"]),
-    file:delete(filename:join([ErtsBinDir, "erl"])),
-    file:delete(filename:join([ErtsBinDir, "start"])),
-    file:delete(filename:join([ErtsBinDir, "start_erl"])),
+    ok = delete_file(filename:join([ErtsBinDir, "erl"])),
+    ok = delete_file(filename:join([ErtsBinDir, "start"])),
+    ok = delete_file(filename:join([ErtsBinDir, "start_erl"])),
 
     %% Copy .boot to bin/start.boot
     copy_file(RelName++".boot",filename:join([BinDir, "start.boot"])),
@@ -680,7 +680,7 @@ do_upgrade({Cb,InitState},FromVsn,FromAppsVsns,ToRel,ToAppsVsns,InstallDir) ->
     %% even if install_release returned {ok,...} there might be an
     %% emulator restart (instruction restart_emulator), so we must
     %% always make sure the node is running.
-    wait_node_up(current,ToVsn,ToAppsVsns),
+    {ok, _} = wait_node_up(current,ToVsn,ToAppsVsns),
 
     [{"OTP upgrade test",ToVsn,_,current},
      {"OTP upgrade test",FromVsn,_,permanent}] =
@@ -703,7 +703,7 @@ do_upgrade({Cb,InitState},FromVsn,FromAppsVsns,ToRel,ToAppsVsns,InstallDir) ->
     %% even if install_release returned {ok,...} there might be an
     %% emulator restart (instruction restart_emulator), so we must
     %% always make sure the node is running.
-    wait_node_up(current,FromVsn,FromAppsVsns),
+    {ok, _} = wait_node_up(current,FromVsn,FromAppsVsns),
 
     [{"OTP upgrade test",ToVsn,_,permanent},
      {"OTP upgrade test",FromVsn,_,current}] =
@@ -854,7 +854,7 @@ copy_file(Src, Dest, Opts) ->
     case lists:member(preserve, Opts) of
         true ->
             {ok, FileInfo} = file:read_file_info(Src),
-            file:write_file_info(Dest, FileInfo);
+            ok = file:write_file_info(Dest, FileInfo);
         false ->
             ok
     end.
@@ -862,8 +862,8 @@ copy_file(Src, Dest, Opts) ->
 write_file(FName, Conts) ->
     Enc = file:native_name_encoding(),
     {ok, Fd} = file:open(FName, [write]),
-    file:write(Fd, unicode:characters_to_binary(Conts,Enc,Enc)),
-    file:close(Fd).
+    ok = file:write(Fd, unicode:characters_to_binary(Conts,Enc,Enc)),
+    ok = file:close(Fd).
 
 %% Substitute all occurrences of %Var% for Val in the given scripts
 subst_src_scripts(Scripts, SrcDir, DestDir, Vars, Opts) ->
@@ -944,3 +944,19 @@ rm_rf(Dir) ->
 	_ ->
 	    ok
     end.
+
+delete_file(FileName) ->
+    case file:delete(FileName) of
+        {error, enoent} ->
+            ok;
+        Else ->
+            Else
+    end.
+
+make_dir(Dir) ->
+    case file:make_dir(Dir) of
+        {error, eexist} ->
+            ok;
+        Else ->
+            Else
+    end.
diff --git a/lib/common_test/src/ct_repeat.erl b/lib/common_test/src/ct_repeat.erl
index 31c5755c7e..dac596a135 100644
--- a/lib/common_test/src/ct_repeat.erl
+++ b/lib/common_test/src/ct_repeat.erl
@@ -44,13 +44,13 @@ loop_test(If,Args) when is_list(Args) ->
 	    false;
 	E = {error,_} ->
 	    io:format("Common Test error: ~p\n\n",[E]),
-	    file:set_cwd(Cwd),
+	    ok = file:set_cwd(Cwd),
 	    E;
 	{repeat,N} ->
 	    io:format("\nCommon Test: Will repeat tests ~w times.\n\n",[N]),
 	    Args1 = [{loop_info,[{repeat,1,N}]} | Args],
 	    Result = loop(If,repeat,0,N,undefined,Args1,undefined,[]),
-	    file:set_cwd(Cwd),
+	    ok = file:set_cwd(Cwd),
 	    Result;
 	{stop_time,StopTime} ->
 	    Result =
@@ -76,7 +76,7 @@ loop_test(If,Args) when is_list(Args) ->
 			Args1 = [{loop_info,[{stop_time,Secs,StopTime,1}]} | Args],
 			loop(If,stop_time,0,Secs,StopTime,Args1,TPid,[])
 		end,
-	    file:set_cwd(Cwd),
+	    ok = file:set_cwd(Cwd),
 	    Result
     end.
     
diff --git a/lib/common_test/src/ct_rpc.erl b/lib/common_test/src/ct_rpc.erl
index cbcc212bb8..b4a0bc9d74 100644
--- a/lib/common_test/src/ct_rpc.erl
+++ b/lib/common_test/src/ct_rpc.erl
@@ -81,7 +81,7 @@ app_node(App, [], _, _) ->
 app_node(App, _Candidates = [CandidateNode | Nodes], FailOnBadRPC, Cookie) -> 
     Cookie0 = set_the_cookie(Cookie),
     Result = rpc:call(CandidateNode, application, which_applications, []),
-    set_the_cookie(Cookie0),
+    _ = set_the_cookie(Cookie0),
     case Result of
 	{badrpc,Reason} when FailOnBadRPC == true ->
 	    ct:fail({Reason,CandidateNode});
@@ -145,7 +145,7 @@ call({Fun, FunArgs}, Module, Function, Args, TimeOut, Cookie) ->
 call(Node, Module, Function, Args, TimeOut, Cookie) when is_atom(Node) ->
     Cookie0 = set_the_cookie(Cookie),
     Result = rpc:call(Node, Module, Function, Args, TimeOut),
-    set_the_cookie(Cookie0),
+    _ = set_the_cookie(Cookie0),
     Result.    
 
 %%% @spec cast(Node, Module, Function, Args) -> ok
@@ -190,7 +190,7 @@ cast({Fun, FunArgs}, Module, Function, Args, Cookie) ->
 cast(Node, Module, Function, Args, Cookie) when is_atom(Node) ->
     Cookie0 = set_the_cookie(Cookie),
     true = rpc:cast(Node, Module, Function, Args),
-    set_the_cookie(Cookie0),
+    _ = set_the_cookie(Cookie0),
     ok.
 
 
diff --git a/lib/common_test/src/ct_run.erl b/lib/common_test/src/ct_run.erl
index 1e5f935198..fbb9c7ab60 100644
--- a/lib/common_test/src/ct_run.erl
+++ b/lib/common_test/src/ct_run.erl
@@ -400,21 +400,21 @@ run_or_refresh(Opts = #opts{logdir = LogDir}, Args) ->
 			  [RefreshDir] -> ?abs(RefreshDir)
 		      end,
 	    {ok,Cwd} = file:get_cwd(),
-	    file:set_cwd(LogDir1),
+	    ok = file:set_cwd(LogDir1),
 	    %% give the shell time to print version etc
 	    timer:sleep(500),
 	    io:nl(),
 	    case catch ct_logs:make_all_runs_index(refresh) of
 		{'EXIT',ARReason} ->
-		    file:set_cwd(Cwd),
+		    ok = file:set_cwd(Cwd),
 		    {error,{all_runs_index,ARReason}};
 		_ ->
 		    case catch ct_logs:make_all_suites_index(refresh) of
 			{'EXIT',ASReason} ->
-			    file:set_cwd(Cwd),
+			    ok = file:set_cwd(Cwd),
 			    {error,{all_suites_index,ASReason}};
 			_ ->
-			    file:set_cwd(Cwd),
+			    ok = file:set_cwd(Cwd),
 			    io:format("Logs in ~ts refreshed!~n~n",
 				      [LogDir1]),
 			    timer:sleep(500), % time to flush io before quitting
@@ -756,8 +756,8 @@ script_start4(#opts{label = Label, profile = Profile,
 		  {ct_hooks, CTHooks},
 		  {enable_builtin_hooks,EnableBuiltinHooks}]) of
 	ok ->
-	    ct_util:start(interactive, LogDir,
-			  add_verbosity_defaults(Verbosity)),
+	    _ = ct_util:start(interactive, LogDir,
+			      add_verbosity_defaults(Verbosity)),
 	    ct_util:set_testdata({logopts, LogOpts}),
 	    log_ts_names(Specs),
 	    io:nl(),
@@ -901,9 +901,8 @@ install(Opts, LogDir) ->
 	    VarFile = variables_file_name(LogDir),
 	    case file:open(VarFile, [write]) of
 		{ok,Fd} ->
-		    [io:format(Fd, "~p.\n", [Opt]) || Opt <- ConfOpts ],
-		    file:close(Fd),
-		    ok;
+		    _ = [io:format(Fd, "~p.\n", [Opt]) || Opt <- ConfOpts],
+		    ok = file:close(Fd);
 		{error,Reason} ->
 		    io:format("CT failed to install configuration data. Please "
 			      "verify that the log directory exists and that "
@@ -960,7 +959,7 @@ run_test1(StartOpts) when is_list(StartOpts) ->
 		    false ->
 			case catch run_test2(StartOpts) of
 			    {'EXIT',Reason} ->
-				file:set_cwd(Cwd),
+				ok = file:set_cwd(Cwd),
 				{error,Reason};
 			    Result ->
 				Result
@@ -971,7 +970,7 @@ run_test1(StartOpts) when is_list(StartOpts) ->
 	    stop_trace(Tracing),
 	    exit(Res);
 	RefreshDir ->
-	    refresh_logs(?abs(RefreshDir)),
+	    ok = refresh_logs(?abs(RefreshDir)),
 	    exit(done)
     end.
 
@@ -1209,7 +1208,6 @@ run_all_specs([], _, _, TotResult) ->
     end;
 
 run_all_specs([{Specs,TS} | TSs], Opts, StartOpts, TotResult) ->
-    log_ts_names(Specs),
     Combined = #opts{config = TSConfig} = combine_test_opts(TS, Specs, Opts),
     AllConfig = merge_vals([Opts#opts.config, TSConfig]),
     try run_one_spec(TS, 
@@ -1430,7 +1428,7 @@ run_testspec1(TestSpec) ->
     io:format("~nCommon Test starting (cwd is ~ts)~n~n", [Cwd]),
     case catch run_testspec2(TestSpec) of
 	{'EXIT',Reason} ->
-	    file:set_cwd(Cwd),
+	    ok = file:set_cwd(Cwd),
 	    exit({error,Reason});
 	Result ->
 	    exit(Result)
@@ -1562,15 +1560,15 @@ refresh_logs(LogDir) ->
 	_ ->
 	    case catch ct_logs:make_all_suites_index(refresh) of
 		{'EXIT',ASReason} ->
-		    file:set_cwd(Cwd),
+		    ok = file:set_cwd(Cwd),
 		    {error,{all_suites_index,ASReason}};
 		_ ->
 		    case catch ct_logs:make_all_runs_index(refresh) of
 			{'EXIT',ARReason} ->
-			    file:set_cwd(Cwd),
+			    ok = file:set_cwd(Cwd),
 			    {error,{all_runs_index,ARReason}};
 			_ ->
-			    file:set_cwd(Cwd),
+			    ok = file:set_cwd(Cwd),
 			    io:format("Logs in ~ts refreshed!~n",[LogDir]),
 			    ok
 		    end
@@ -1610,22 +1608,34 @@ delistify(E)   -> E.
 %%% @hidden
 %%% @equiv ct:run/3
 run(TestDir, Suite, Cases) ->
-    install([]),
-    reformat_result(catch do_run(tests(TestDir, Suite, Cases), [])).
+    case install([]) of
+	ok ->
+	    reformat_result(catch do_run(tests(TestDir, Suite, Cases), []));
+	Error ->
+	    Error
+    end.
 
 %%%-----------------------------------------------------------------
 %%% @hidden
 %%% @equiv ct:run/2
 run(TestDir, Suite) when is_list(TestDir), is_integer(hd(TestDir)) ->
-    install([]),
-    reformat_result(catch do_run(tests(TestDir, Suite), [])).
+    case install([]) of
+	ok ->
+	    reformat_result(catch do_run(tests(TestDir, Suite), []));
+	Error ->
+	    Error
+    end.
 
 %%%-----------------------------------------------------------------
 %%% @hidden
 %%% @equiv ct:run/1
 run(TestDirs) ->
-    install([]),
-    reformat_result(catch do_run(tests(TestDirs), [])).
+    case install([]) of
+	ok ->
+	    reformat_result(catch do_run(tests(TestDirs), []));
+	Error ->
+	    Error
+    end.
 
 reformat_result({'EXIT',{user_error,Reason}}) ->
     {error,Reason};
@@ -2017,7 +2027,7 @@ save_make_errors(Errors) ->
 		"Error compiling or locating the "
 		"following suites: ~n~p",[Suites]),
     %% save the info for logger
-    file:write_file(?missing_suites_info,term_to_binary(Errors)),
+    ok = file:write_file(?missing_suites_info,term_to_binary(Errors)),
     Errors.
 
 get_bad_suites([{{_TestDir,_Suite},Failed}|Errors], BadSuites) ->
@@ -2234,7 +2244,7 @@ do_run_test(Tests, Skip, Opts0) ->
 		end,
 	    application:set_env(test_server, esc_chars, EscChars),
 
-	    test_server_ctrl:start_link(local),
+	    {ok, _} = test_server_ctrl:start_link(local),
 
 	    %% let test_server expand the test tuples and count no of cases
 	    {Suites,NoOfCases} = count_test_cases(Tests, Skip),
@@ -2295,7 +2305,7 @@ do_run_test(Tests, Skip, Opts0) ->
 	    lists:foreach(fun(Suite) ->
 				  maybe_cleanup_interpret(Suite, Opts#opts.step)
 			  end, CleanUp),
-	    [code:del_path(Dir) || Dir <- AddedToPath],
+	    _ = [code:del_path(Dir) || Dir <- AddedToPath],
 
 	    %% If a severe error has occurred in the test_server,
 	    %% we will generate an exception here.
@@ -2422,7 +2432,7 @@ count_test_cases(Tests, Skip) ->
     SendResult = fun(Me, Result) -> Me ! {no_of_cases,Result} end,
     TSPid = test_server_ctrl:start_get_totals(SendResult),
     Ref = erlang:monitor(process, TSPid),
-    add_jobs(Tests, Skip, #opts{}, []),
+    _ = add_jobs(Tests, Skip, #opts{}, []),
     Counted = (catch count_test_cases1(length(Tests), 0, [], Ref)),
     erlang:demonitor(Ref, [flush]),
     case Counted of
@@ -2776,14 +2786,14 @@ maybe_interpret1(Suite, Cases, StepOpts) when is_list(Cases) ->
 
 maybe_interpret2(Suite, Cases, StepOpts) ->
     set_break_on_config(Suite, StepOpts),
-    [begin try i:ib(Suite, Case, 1) of
+    _ = [begin try i:ib(Suite, Case, 1) of
 	       _ -> ok
 	   catch
 	       _:_Error ->
 		   io:format(user, "Invalid breakpoint: ~w:~w/1~n",
 			     [Suite,Case])
 	   end
-     end || Case <- Cases, is_atom(Case)],
+ 	 end || Case <- Cases, is_atom(Case)],
     test_server_ctrl:multiply_timetraps(infinity),
     WinOp = case lists:member(keep_inactive, ensure_atom(StepOpts)) of
 		true -> no_kill;
@@ -2802,12 +2812,12 @@ set_break_on_config(Suite, StepOpts) ->
 					false -> ok
 				    end
 			    end,
-	    SetBPIfExists(init_per_suite, 1),
-	    SetBPIfExists(init_per_group, 2),
-	    SetBPIfExists(init_per_testcase, 2),
-	    SetBPIfExists(end_per_testcase, 2),
-	    SetBPIfExists(end_per_group, 2),
-	    SetBPIfExists(end_per_suite, 1);
+	    ok = SetBPIfExists(init_per_suite, 1),
+	    ok = SetBPIfExists(init_per_group, 2),
+	    ok = SetBPIfExists(init_per_testcase, 2),
+	    ok = SetBPIfExists(end_per_testcase, 2),
+	    ok = SetBPIfExists(end_per_group, 2),
+	    ok = SetBPIfExists(end_per_suite, 1);
 	false ->
 	    ok
     end.
@@ -2984,31 +2994,31 @@ add_verbosity_defaults(VLvls) ->
 %% relative dirs "post run_test erl_args" is not kept!
 rel_to_abs(CtArgs) ->
     {PA,PZ} = get_pa_pz(CtArgs, [], []),
-    [begin
+    _ = [begin
 	 Dir = rm_trailing_slash(D),
 	 Abs = make_abs(Dir),
-	 if Dir /= Abs ->
-		 code:del_path(Dir),
-		 code:del_path(Abs),		 
+	 _ = if Dir /= Abs ->
+		 _ = code:del_path(Dir),
+		 _ = code:del_path(Abs),		 
 		 io:format(user, "Converting ~p to ~p and re-inserting "
 			   "with add_pathz/1~n",
 			   [Dir, Abs]);
 	    true ->
-		 code:del_path(Dir)
+		 _ = code:del_path(Dir)
 	 end,
 	 code:add_pathz(Abs)	 
      end || D <- PZ],
-    [begin
+    _ = [begin
 	 Dir = rm_trailing_slash(D),
 	 Abs = make_abs(Dir),
-	 if Dir /= Abs ->
-		 code:del_path(Dir),
-		 code:del_path(Abs),		 
+	 _ = if Dir /= Abs ->
+		 _ = code:del_path(Dir),
+		 _ = code:del_path(Abs),		 
 		 io:format(user, "Converting ~p to ~p and re-inserting "
 			   "with add_patha/1~n",
 			   [Dir, Abs]);
 	    true ->
-		 code:del_path(Dir)
+		 _ = code:del_path(Dir)
 	 end,
 	 code:add_patha(Abs)
      end || D <- PA],
diff --git a/lib/common_test/src/ct_slave.erl b/lib/common_test/src/ct_slave.erl
index 3ad3937548..571958ca03 100644
--- a/lib/common_test/src/ct_slave.erl
+++ b/lib/common_test/src/ct_slave.erl
@@ -325,7 +325,7 @@ do_start(Host, Node, Options) ->
 	    Functions
     end,
     MasterHost = gethostname(),
-    if
+    _ = if
 	MasterHost == Host ->
 	    spawn_local_node(Node, Options);
 	true->
@@ -359,7 +359,7 @@ do_start(Host, Node, Options) ->
         pang->
 	    {error, boot_timeout, ENode}
     end,
-    case Result of
+    _ = case Result of
 	{ok, ENode}->
 	     ok;
 	{error, Timeout, ENode}
@@ -422,7 +422,7 @@ spawn_remote_node(Host, Node, Options) ->
 	{_, _}->
 	    [{user, Username}, {password, Password}]
     end ++ [{silently_accept_hosts, true}] ++ SSHOpts,
-    application:ensure_all_started(ssh),
+    {ok, _} = application:ensure_all_started(ssh),
     {ok, SSHConnRef} = ssh:connect(atom_to_list(Host), SSHPort, SSHOptions),
     {ok, SSHChannelId} = ssh_connection:session_channel(SSHConnRef, infinity),
     ssh_setenv(SSHConnRef, SSHChannelId, Env),
diff --git a/lib/common_test/src/ct_snmp.erl b/lib/common_test/src/ct_snmp.erl
index bb0167eb22..2c59b19196 100644
--- a/lib/common_test/src/ct_snmp.erl
+++ b/lib/common_test/src/ct_snmp.erl
@@ -221,9 +221,17 @@ start(Config, MgrAgentConfName, SnmpAppConfName) ->
 		Config, SysName, AgentManagerIP, IP),
     setup_manager(StartManager, MgrAgentConfName, SnmpAppConfName, 
 		  Config, AgentManagerIP),
-    application:start(snmp),
+    ok = start_application(snmp),
 
     manager_register(StartManager, MgrAgentConfName).
+
+start_application(App) ->
+    case application:start(App) of
+        {error, {already_started, App}} ->
+            ok;
+        Else ->
+            Else
+    end.
  
 %%% @spec stop(Config) -> ok
 %%%      Config = [{Key, Value}]
@@ -233,8 +241,8 @@ start(Config, MgrAgentConfName, SnmpAppConfName) ->
 %%% @doc Stops the snmp manager and/or agent removes all files created.
 stop(Config) ->
     PrivDir = ?config(priv_dir, Config),
-    application:stop(snmp),
-    application:stop(mnesia),
+    ok = application:stop(snmp),
+    ok = application:stop(mnesia),
     MgrDir =  filename:join(PrivDir,"mgr"),
     ConfDir = filename:join(PrivDir, "conf"),
     DbDir = filename:join(PrivDir,"db"),
@@ -311,7 +319,7 @@ set_info(Config) ->
     SetLogFile = filename:join(PrivDir, ?CT_SNMP_LOG_FILE),
     case file:consult(SetLogFile) of
 	{ok, SetInfo} ->
-	    file:delete(SetLogFile),
+	    ok = delete_file(SetLogFile),
 	    lists:reverse(SetInfo);
 	_ ->
 	    []
@@ -513,7 +521,7 @@ unload_mibs(Mibs) ->
 prepare_snmp_env() ->
     %% To make sure application:set_env is not overwritten by any
     %% app-file settings.
-    application:load(snmp),
+    _ = application:load(snmp),
     
     %% Fix for older versions of snmp where there are some
     %% inappropriate default values for alway starting an 
@@ -533,7 +541,7 @@ setup_manager(true, MgrConfName, SnmpConfName, Config, IP) ->
     Users = [],
     Agents = [],
     Usms = [],
-    file:make_dir(MgrDir),
+    ok = make_dir(MgrDir),
    
     snmp_config:write_manager_snmp_files(MgrDir, IP, Port, MaxMsgSize, 
 					 EngineID, Users, Agents, Usms),
@@ -549,7 +557,7 @@ setup_agent(false,_, _, _, _, _, _) ->
     ok;
 setup_agent(true, AgentConfName, SnmpConfName, 
 	    Config, SysName, ManagerIP, AgentIP) ->
-    application:start(mnesia),
+    ok = start_application(mnesia),
     PrivDir = ?config(priv_dir, Config),
     Vsns = ct:get_config({AgentConfName, agent_vsns}, ?CONF_FILE_VER),
     TrapUdp = ct:get_config({AgentConfName, agent_trap_udp}, ?TRAP_UDP),
@@ -565,8 +573,8 @@ setup_agent(true, AgentConfName, SnmpConfName,
     
     ConfDir = filename:join(PrivDir, "conf"),
     DbDir = filename:join(PrivDir,"db"),
-    file:make_dir(ConfDir),
-    file:make_dir(DbDir),    
+    ok = make_dir(ConfDir),
+    ok = make_dir(DbDir),    
     snmp_config:write_agent_snmp_files(ConfDir, Vsns, ManagerIP, TrapUdp, 
 				       AgentIP, AgentUdp, SysName, 
 				       NotifType, SecType, Passwd,
@@ -684,7 +692,7 @@ log(PrivDir, Agent, {_, _, Varbinds}, NewVarsAndVals) ->
     File = filename:join(PrivDir, ?CT_SNMP_LOG_FILE),
     {ok, Fd} = file:open(File, [write, append]),
     io:format(Fd, "~p.~n", [{Agent, OldVarsAndVals, NewVarsAndVals}]),
-    file:close(Fd),
+    ok = file:close(Fd),
     ok.
 %%%---------------------------------------------------------------------------
 del_dir(Dir) ->
@@ -692,7 +700,7 @@ del_dir(Dir) ->
     FullPathFiles = lists:map(fun(File) -> filename:join(Dir, File) end,
 			      Files),
     lists:foreach(fun file:delete/1, FullPathFiles), 
-    file:del_dir(Dir),
+    ok = delete_dir(Dir),
     ok.
 %%%---------------------------------------------------------------------------
 agent_conf(Agent, MgrAgentConfName) ->
@@ -738,8 +746,8 @@ override_contexts(Config, {data_dir_file, File}) ->
 override_contexts(Config, Contexts) ->
     Dir = filename:join(?config(priv_dir, Config),"conf"),
     File = filename:join(Dir,"context.conf"),
-    file:delete(File),
-    snmp_config:write_agent_context_config(Dir, "", Contexts).
+    ok = delete_file(File),
+    ok = snmp_config:write_agent_context_config(Dir, "", Contexts).
 		
 %%%---------------------------------------------------------------------------
 override_sysinfo(_, undefined) ->
@@ -754,8 +762,8 @@ override_sysinfo(Config, {data_dir_file, File}) ->
 override_sysinfo(Config, SysInfo) ->   
     Dir = filename:join(?config(priv_dir, Config),"conf"),
     File = filename:join(Dir,"standard.conf"),
-    file:delete(File),
-    snmp_config:write_agent_standard_config(Dir, "", SysInfo).
+    ok = delete_file(File),
+    ok = snmp_config:write_agent_standard_config(Dir, "", SysInfo).
 
 %%%---------------------------------------------------------------------------
 override_target_address(_, undefined) ->
@@ -769,8 +777,8 @@ override_target_address(Config, {data_dir_file, File}) ->
 override_target_address(Config, TargetAddressConf) ->
     Dir = filename:join(?config(priv_dir, Config),"conf"),
     File = filename:join(Dir,"target_addr.conf"),
-    file:delete(File),
-    snmp_config:write_agent_target_addr_config(Dir, "", TargetAddressConf).
+    ok = delete_file(File),
+    ok = snmp_config:write_agent_target_addr_config(Dir, "", TargetAddressConf).
 
 
 %%%---------------------------------------------------------------------------
@@ -785,8 +793,8 @@ override_target_params(Config, {data_dir_file, File}) ->
 override_target_params(Config, TargetParamsConf) ->
     Dir = filename:join(?config(priv_dir, Config),"conf"),
     File = filename:join(Dir,"target_params.conf"),
-    file:delete(File),
-    snmp_config:write_agent_target_params_config(Dir, "", TargetParamsConf). 
+    ok = delete_file(File),
+    ok = snmp_config:write_agent_target_params_config(Dir, "", TargetParamsConf).
 
 %%%---------------------------------------------------------------------------
 override_notify(_, undefined) ->
@@ -800,8 +808,8 @@ override_notify(Config, {data_dir_file, File}) ->
 override_notify(Config, NotifyConf) ->
     Dir = filename:join(?config(priv_dir, Config),"conf"),
     File = filename:join(Dir,"notify.conf"),
-    file:delete(File),
-    snmp_config:write_agent_notify_config(Dir, "", NotifyConf).
+    ok = delete_file(File),
+    ok = snmp_config:write_agent_notify_config(Dir, "", NotifyConf).
 
 %%%---------------------------------------------------------------------------
 override_usm(_, undefined) ->
@@ -815,8 +823,8 @@ override_usm(Config, {data_dir_file, File}) ->
 override_usm(Config, UsmConf) ->
     Dir = filename:join(?config(priv_dir, Config),"conf"),
     File = filename:join(Dir,"usm.conf"),
-    file:delete(File),
-    snmp_config:write_agent_usm_config(Dir, "", UsmConf).
+    ok = delete_file(File),
+    ok = snmp_config:write_agent_usm_config(Dir, "", UsmConf).
 
 %%%--------------------------------------------------------------------------
 override_community(_, undefined) ->
@@ -830,8 +838,8 @@ override_community(Config, {data_dir_file, File}) ->
 override_community(Config, CommunityConf) ->
     Dir = filename:join(?config(priv_dir, Config),"conf"),
     File = filename:join(Dir,"community.conf"),
-    file:delete(File),
-    snmp_config:write_agent_community_config(Dir, "", CommunityConf).
+    ok = delete_file(File),
+    ok = snmp_config:write_agent_community_config(Dir, "", CommunityConf).
    
 %%%---------------------------------------------------------------------------
 
@@ -846,8 +854,8 @@ override_vacm(Config, {data_dir_file, File}) ->
 override_vacm(Config, VacmConf) ->
     Dir = filename:join(?config(priv_dir, Config),"conf"),
     File = filename:join(Dir,"vacm.conf"),
-    file:delete(File),
-    snmp_config:write_agent_vacm_config(Dir, "", VacmConf).
+    ok = delete_file(File),
+    ok = snmp_config:write_agent_vacm_config(Dir, "", VacmConf).
 
 %%%---------------------------------------------------------------------------
 
@@ -861,3 +869,21 @@ while_ok(Fun,[H|T]) ->
     end;
 while_ok(_Fun,[]) ->
     ok.
+
+delete_file(FileName) ->
+    case file:delete(FileName) of
+        {error, enoent} -> ok;
+        Else -> Else
+    end.
+
+make_dir(Dir) ->
+    case file:make_dir(Dir) of
+        {error, eexist} -> ok;
+        Else -> Else
+    end.
+
+delete_dir(Dir) ->
+    case file:del_dir(Dir) of
+        {error, enoent} -> ok;
+        Else -> Else
+    end.
diff --git a/lib/common_test/src/ct_ssh.erl b/lib/common_test/src/ct_ssh.erl
index 92d912052e..6ab3bf036c 100644
--- a/lib/common_test/src/ct_ssh.erl
+++ b/lib/common_test/src/ct_ssh.erl
@@ -962,8 +962,8 @@ init(KeyOrName, {ConnType,Addr,Port}, AllOpts) ->
 		    end, [], AllOpts1),
     FinalOptions = [{silently_accept_hosts,true},
 		    {user_interaction,false} | Options],
-    crypto:start(),
-    ssh:start(),
+    _ = crypto:start(),
+    _ = ssh:start(),
     Result = case ConnType of
 		 ssh ->
 		     ssh:connect(Addr, Port, FinalOptions);
diff --git a/lib/common_test/src/ct_telnet.erl b/lib/common_test/src/ct_telnet.erl
index f5f4f648f4..8fb411ec4f 100644
--- a/lib/common_test/src/ct_telnet.erl
+++ b/lib/common_test/src/ct_telnet.erl
@@ -605,7 +605,7 @@ init(Name,{Ip,Port,Type},{TargetMod,KeepAlive,Extra}) ->
 		 set_telnet_defaults(Settings,#state{})				    
 	 end,
     %% Handle old user versions of TargetMod
-    code:ensure_loaded(TargetMod),
+    _ = code:ensure_loaded(TargetMod),
     try
 	case erlang:function_exported(TargetMod,connect,7) of
 	    true ->
@@ -688,7 +688,7 @@ handle_msg({cmd,Cmd,Opts},State) ->
     debug_cont_gen_log("Throwing Buffer:",[]),
     debug_log_lines(State#state.buffer),
 
-    case {State#state.type,State#state.prompt} of
+    _ = case {State#state.type,State#state.prompt} of
 	{ts,_} ->
 	    silent_teln_expect(State#state.name,
 			       State#state.teln_pid,
@@ -735,7 +735,7 @@ handle_msg({send,Cmd,Opts},State) ->
     debug_cont_gen_log("Throwing Buffer:",[]),
     debug_log_lines(State#state.buffer),
     
-    case {State#state.type,State#state.prompt} of
+    _ = case {State#state.type,State#state.prompt} of
 	{ts,_} -> 
 	    silent_teln_expect(State#state.name,
 			       State#state.teln_pid,
diff --git a/lib/common_test/src/ct_telnet_client.erl b/lib/common_test/src/ct_telnet_client.erl
index 1f1311776f..5df7e279ac 100644
--- a/lib/common_test/src/ct_telnet_client.erl
+++ b/lib/common_test/src/ct_telnet_client.erl
@@ -272,7 +272,7 @@ send(Data, Sock, ConnName) ->
 		_:_ -> ok
 	    end
     end,
-    gen_tcp:send(Sock, Data),
+    ok = gen_tcp:send(Sock, Data),
     ok.
 
 %% [IAC,IAC] = buffer data value 255
@@ -284,7 +284,7 @@ check_msg(Sock, [?IAC | Cs], Acc) ->
     case get_cmd(Cs) of
 	{Cmd,Cs1} ->
 	    cmd_dbg("Got",Cmd),
-	    respond_cmd(Cmd, Sock),
+	    ok = respond_cmd(Cmd, Sock),
 	    check_msg(Sock, Cs1, Acc); 
 	error ->
 	    Acc
diff --git a/lib/common_test/src/ct_util.erl b/lib/common_test/src/ct_util.erl
index d5a8e3fbc0..82a8743cf0 100644
--- a/lib/common_test/src/ct_util.erl
+++ b/lib/common_test/src/ct_util.erl
@@ -131,14 +131,14 @@ do_start(Parent, Mode, LogDir, Verbosity) ->
     create_table(?suite_table,#suite_data.key),
 
     create_table(?verbosity_table,1),
-    [ets:insert(?verbosity_table,{Cat,Lvl}) || {Cat,Lvl} <- Verbosity],
+    _ = [ets:insert(?verbosity_table,{Cat,Lvl}) || {Cat,Lvl} <- Verbosity],
 
     {ok,StartDir} = file:get_cwd(),
     case file:set_cwd(LogDir) of
 	ok -> ok;
 	E -> exit(E)
     end,
-    DoExit = fun(Reason) -> file:set_cwd(StartDir), exit(Reason) end,
+    DoExit = fun(Reason) -> ok = file:set_cwd(StartDir), exit(Reason) end,
     Opts = case read_opts() of
 	       {ok,Opts1} ->
 		   Opts1;
@@ -169,7 +169,7 @@ do_start(Parent, Mode, LogDir, Verbosity) ->
     end,
 
     %% add user event handlers
-    case lists:keysearch(event_handler,1,Opts) of
+    _ = case lists:keysearch(event_handler,1,Opts) of
 	{value,{_,Handlers}} ->
 	    Add = fun({H,Args}) ->
 			  case catch gen_event:add_handler(?CT_EVMGR_REF,H,Args) of
@@ -195,7 +195,7 @@ do_start(Parent, Mode, LogDir, Verbosity) ->
 			   data={StartTime,
 				 lists:flatten(TestLogDir)}}),
     %% Initialize ct_hooks
-    try ct_hooks:init(Opts) of
+    _ = try ct_hooks:init(Opts) of
 	ok ->
 	    Parent ! {self(),started};
 	{fail,CTHReason} ->
@@ -228,7 +228,8 @@ create_table(TableName,KeyPos) ->
     create_table(TableName,set,KeyPos).
 create_table(TableName,Type,KeyPos) ->
     catch ets:delete(TableName),
-    ets:new(TableName,[Type,named_table,public,{keypos,KeyPos}]).
+    _ = ets:new(TableName,[Type,named_table,public,{keypos,KeyPos}]),
+    ok.
 
 read_opts() ->
     case file:consult(ct_run:variables_file_name("./")) of
@@ -473,7 +474,7 @@ loop(Mode,TestData,StartDir) ->
 	    ct_logs:close(Info, StartDir),
 	    ct_event:stop(),
 	    ct_config:stop(),
-	    file:set_cwd(StartDir),
+	    ok = file:set_cwd(StartDir),
 	    return(From, Info);
 	{Ref, _Msg} when is_reference(Ref) ->
 	    %% This clause is used when doing cast operations.
@@ -505,7 +506,7 @@ loop(Mode,TestData,StartDir) ->
 		    %% Let process crash in case of error, this shouldn't happen!
 		    io:format("\n\nct_util_server got EXIT "
 			      "from ~w: ~p\n\n", [Pid,Reason]),
-		    file:set_cwd(StartDir),
+		    ok = file:set_cwd(StartDir),
 		    exit(Reason)
 	    end
     end.
@@ -1035,10 +1036,12 @@ call(Msg, Timeout) ->
     end.
 
 return({To,Ref},Result) ->
-    To ! {Ref, Result}.
+    To ! {Ref, Result},
+    ok.
 
 cast(Msg) ->
-    ct_util_server ! {Msg, {ct_util_server, make_ref()}}.
+    ct_util_server ! {Msg, {ct_util_server, make_ref()}},
+    ok.
 
 seconds(T) ->
     test_server:seconds(T).
@@ -1074,7 +1077,7 @@ abs_name2([],Acc) ->
 open_url(iexplore, Args, URL) ->
     {ok,R} = win32reg:open([read]),
     ok = win32reg:change_key(R,"applications\\iexplore.exe\\shell\\open\\command"),
-    case win32reg:values(R) of
+    _ = case win32reg:values(R) of
 	{ok, Paths} ->
 	    Path = proplists:get_value(default, Paths),
 	    [Cmd | _] = string:tokens(Path, "%"),
diff --git a/lib/common_test/src/ct_webtool.erl b/lib/common_test/src/ct_webtool.erl
index 6cbcd98cc3..87af442fd3 100644
--- a/lib/common_test/src/ct_webtool.erl
+++ b/lib/common_test/src/ct_webtool.erl
@@ -84,27 +84,27 @@
 %% Function = {FunctionName,Arity} | FunctionName |
 %%            {Module, FunctionName, Arity} | {Module,FunctionName}
 debug(F) -> 
-    ttb:tracer(all,[{file,"webtool.trc"}]), % tracing all nodes
-    ttb:p(all,[call,timestamp]),
+    {ok, _} = ttb:tracer(all,[{file,"webtool.trc"}]), % tracing all nodes
+    {ok, _} = ttb:p(all,[call,timestamp]),
     MS = [{'_',[],[{return_trace},{message,{caller}}]}],
-    tp(F,MS),
-    ttb:ctp(?MODULE,stop_debug), % don't want tracing of the stop_debug func
+    _ = tp(F,MS),
+    {ok, _} = ttb:ctp(?MODULE,stop_debug), % don't want tracing of the stop_debug func
     ok.
 tp(local,MS) -> % all functions
     ttb:tpl(?MODULE,MS);
 tp(global,MS) -> % all exported functions
     ttb:tp(?MODULE,MS);
 tp([{M,F,A}|T],MS) -> % Other module
-    ttb:tpl(M,F,A,MS),
+    {ok, _} = ttb:tpl(M,F,A,MS),
     tp(T,MS);
 tp([{M,F}|T],MS) when is_atom(F) -> % Other module
-    ttb:tpl(M,F,MS),
+    {ok, _} = ttb:tpl(M,F,MS),
     tp(T,MS);
 tp([{F,A}|T],MS) -> % function/arity
-    ttb:tpl(?MODULE,F,A,MS),
+    {ok, _} = ttb:tpl(?MODULE,F,A,MS),
     tp(T,MS);
 tp([F|T],MS) -> % function
-    ttb:tpl(?MODULE,F,MS),
+    {ok, _} = ttb:tpl(?MODULE,F,MS),
     tp(T,MS);
 tp([],_MS) ->
     ok.
@@ -112,10 +112,10 @@ stop_debug() ->
     ttb:stop([format]).
 
 debug_app(Mod) ->
-    ttb:tracer(all,[{file,"webtool_app.trc"},{handler,{fun out/4,true}}]),
-    ttb:p(all,[call,timestamp]),
+    {ok, _} = ttb:tracer(all,[{file,"webtool_app.trc"},{handler,{fun out/4,true}}]),
+    {ok, _} = ttb:p(all,[call,timestamp]),
     MS = [{'_',[],[{return_trace},{message,{caller}}]}],
-    ttb:tp(Mod,MS),
+    {ok, _} = ttb:tp(Mod,MS),
     ok.
    
 out(_,{trace_ts,Pid,call,MFA={M,F,A},{W,_,_},TS},_,S) 
@@ -145,7 +145,7 @@ script_start([App]) ->
     script_start([App,DefaultBrowser]);
 script_start([App,Browser]) ->
     io:format("Starting webtool...\n"),
-    start(),
+    {ok, _} = start(),
     AvailableApps = get_applications(),
     {OSType,_} = os:type(),
     case lists:keysearch(App,1,AvailableApps) of
@@ -159,14 +159,14 @@ script_start([App,Browser]) ->
 		      _ -> 
 			  "http://localhost:" ++ PortStr ++ "/" ++ StartPage
 		  end,
-	    case Browser of 
+	    _ = case Browser of 
 		none ->
 		    ok;
                 iexplore when OSType == win32->
                     io:format("Starting internet explorer...\n"),
                     {ok,R} = win32reg:open(""),
 		    Key="\\local_machine\\SOFTWARE\\Microsoft\\IE Setup\\Setup",
-                    win32reg:change_key(R,Key),
+                    ok = win32reg:change_key(R,Key),
                     {ok,Val} = win32reg:value(R,"Path"),
 		    IExplore=filename:join(win32reg:expand(Val),"iexplore.exe"),
                     os:cmd("\"" ++ IExplore ++ "\" " ++ Url);
@@ -186,7 +186,7 @@ script_start([App,Browser]) ->
 			{Port,{exit_status,_Error}} ->
 			    io:format(" not running, starting ~w...\n",
 				      [Browser]),
-			    os:cmd(BStr ++ " " ++ Url),
+			    _ = os:cmd(BStr ++ " " ++ Url),
 			    ok
 		    after ?SEND_URL_TIMEOUT ->
 			    io:format(" failed, starting ~w...\n",[Browser]),
@@ -206,7 +206,7 @@ script_start([App,Browser]) ->
 
 usage() ->
     io:format("Starting webtool...\n"),
-    start(),
+    {ok, _} = start(),
     Apps = lists:map(fun({A,_}) -> A end,get_applications()),
     io:format(
       "\nUsage: start_webtool application [ browser ]\n"
@@ -254,7 +254,12 @@ start(Path,Port) when is_integer(Port)->
 	
 start(Path,Data0)->
     Data = Data0 ++ rest_of_standard_data(),
-    gen_server:start({local,ct_web_tool},ct_webtool,{Path,Data},[]).
+    case gen_server:start({local,ct_web_tool},ct_webtool,{Path,Data},[]) of
+		{error, {already_started, Pid}} ->
+		    {ok, Pid};
+		Else ->
+		    Else
+    end.
 
 stop()->
     gen_server:call(ct_web_tool,stoppit).
diff --git a/lib/common_test/src/cth_conn_log.erl b/lib/common_test/src/cth_conn_log.erl
index 0501c6ed1c..883da0da0a 100644
--- a/lib/common_test/src/cth_conn_log.erl
+++ b/lib/common_test/src/cth_conn_log.erl
@@ -170,7 +170,7 @@ post_end_per_testcase(TestCase,_Config,Return,CthState) ->
 	end,
     case ct_util:update_testdata(?MODULE, Update) of
 	deleted ->
-	    [ct_util:delete_testdata({?MODULE,ConnMod}) ||
+	    _ = [ct_util:delete_testdata({?MODULE,ConnMod}) ||
 		{ConnMod,_} <- CthState],
 	    error_logger:delete_report_handler(ct_conn_log_h);
 	{error,no_response} ->
diff --git a/lib/common_test/src/erl2html2.erl b/lib/common_test/src/erl2html2.erl
index a1e0bf3879..e819f345de 100644
--- a/lib/common_test/src/erl2html2.erl
+++ b/lib/common_test/src/erl2html2.erl
@@ -62,15 +62,15 @@ convert(File, Dest, InclPath, Header) ->
 		{ok,SFd} ->
 		    case file:open(Dest,[write,raw]) of
 			{ok,DFd} ->
-			    file:write(DFd,[Header,"<pre>\n"]),
+			    ok = file:write(DFd,[Header,"<pre>\n"]),
 			    _Lines = build_html(SFd,DFd,encoding(File),Functions),
-			    file:write(DFd,["</pre>\n",footer(),
+			    ok = file:write(DFd,["</pre>\n",footer(),
 					    "</body>\n</html>\n"]),
 			    %% {_, Time2} = statistics(runtime),
 			    %% io:format("Converted ~p lines in ~.2f Seconds.~n",
 			    %% 	      [_Lines, Time2/1000]),
-			    file:close(SFd),
-			    file:close(DFd),
+			    ok = file:close(SFd),
+			    ok = file:close(DFd),
 			    ok;
 			Error ->
 			    Error
@@ -138,7 +138,7 @@ parse_non_preprocessed_file(File) ->
     case file:open(File, []) of
 	{ok,Epp} ->
 	    Forms = parse_non_preprocessed_file(Epp, File, 1),
-	    file:close(Epp),
+	    ok = file:close(Epp),
 	    {ok,Forms};
 	Error = {error,_E} ->
 	    Error
@@ -205,14 +205,14 @@ build_html(SFd,DFd,Encoding,FuncsAndCs) ->
 %% line of last expression in function found
 build_html(SFd,DFd,Enc,{ok,Str},LastL,FuncsAndCs,_IsFuncDef,{F,LastL}) ->
     LastLineLink = test_server_ctrl:uri_encode(F++"-last_expr",utf8),
-	    file:write(DFd,["<a name=\"",
-			    to_raw_list(LastLineLink,Enc),"\"/>"]),
+	    ok = file:write(DFd,["<a name=\"",
+				 to_raw_list(LastLineLink,Enc),"\"/>"]),
     build_html(SFd,DFd,Enc,{ok,Str},LastL,FuncsAndCs,true,undefined);
 %% function start line found
 build_html(SFd,DFd,Enc,{ok,Str},L0,[{F,A,L0,LastL}|FuncsAndCs],
 	   _IsFuncDef,_FAndLastL) ->
     FALink = test_server_ctrl:uri_encode(F++"-"++integer_to_list(A),utf8),
-    file:write(DFd,["<a name=\"",to_raw_list(FALink,Enc),"\"/>"]),
+    ok = file:write(DFd,["<a name=\"",to_raw_list(FALink,Enc),"\"/>"]),
     build_html(SFd,DFd,Enc,{ok,Str},L0,FuncsAndCs,true,{F,LastL});
 build_html(SFd,DFd,Enc,{ok,Str},L,[{clause,L}|FuncsAndCs],
 	   _IsFuncDef,FAndLastL) ->
@@ -220,7 +220,7 @@ build_html(SFd,DFd,Enc,{ok,Str},L,[{clause,L}|FuncsAndCs],
 build_html(SFd,DFd,Enc,{ok,Str},L,FuncsAndCs,IsFuncDef,FAndLastL) ->
     LStr = line_number(L),
     Str1 = line(Str,IsFuncDef),
-    file:write(DFd,[LStr,Str1]),
+    ok = file:write(DFd,[LStr,Str1]),
     build_html(SFd,DFd,Enc,file:read_line(SFd),L+1,FuncsAndCs,false,FAndLastL);
 build_html(_SFd,_DFd,_Enc,eof,L,_FuncsAndCs,_IsFuncDef,_FAndLastL) ->
     L.
diff --git a/lib/common_test/src/test_server.erl b/lib/common_test/src/test_server.erl
index bd677e971b..924086f2bd 100644
--- a/lib/common_test/src/test_server.erl
+++ b/lib/common_test/src/test_server.erl
@@ -1653,7 +1653,8 @@ messages_get() ->
 %%
 %% Make sure proceeding IO from FromPid won't get rejected
 permit_io(GroupLeader, FromPid) ->
-    GroupLeader ! {permit_io,FromPid}.
+    GroupLeader ! {permit_io,FromPid},
+    ok.
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 %% sleep(Time) -> ok
diff --git a/lib/common_test/src/test_server_ctrl.erl b/lib/common_test/src/test_server_ctrl.erl
index 84e35e7371..b52e4bef9b 100644
--- a/lib/common_test/src/test_server_ctrl.erl
+++ b/lib/common_test/src/test_server_ctrl.erl
@@ -294,7 +294,7 @@ start_link(_) ->
 
 start() ->
     case gen_server:start({local,?MODULE}, ?MODULE, [], []) of
-	{ok, Pid} ->
+	{error, {already_started, Pid}} ->
 	    {ok, Pid};
 	Other ->
 	    Other
@@ -302,7 +302,7 @@ start() ->
 
 start_link() ->
     case gen_server:start_link({local,?MODULE}, ?MODULE, [], []) of
-	{ok, Pid} ->
+	{error, {already_started, Pid}} ->
 	    {ok, Pid};
 	Other ->
 	    Other