Fix deflateParams on zlib 1.2.11

1.2.11 started bailing when avail_out==0 regardless of whether
there's anything to flush or not, and there's no point in adapting
the old method since it was vulnerable to bugs in other zlib
versions which updated the deflate parameters even on failure.

The api_deflateParams test has been expanded accordingly, and two
white-box cases in zip_usage has been updated to make fewer
assumptions about the output; the validity of the compressed data
is what matters, not whether it's exactly the same as the test
vector.

1 files changed, 40 insertions, 6 deletions

diff --git a/lib/kernel/test/zlib_SUITE.erl b/lib/kernel/test/zlib_SUITE.erl
index 1afcd155b3..6f40c74ee8 100644
--- a/lib/kernel/test/zlib_SUITE.erl
+++ b/lib/kernel/test/zlib_SUITE.erl
@@ -213,12 +213,46 @@ api_deflateReset(Config) when is_list(Config) ->
 
 %% Test deflateParams.
 api_deflateParams(Config) when is_list(Config) ->
+    Levels = [none, default, best_speed, best_compression] ++ lists:seq(0, 9),
+    Strategies = [filtered, huffman_only, rle, default],
+
     Z1 = zlib:open(),
     ?m(ok, zlib:deflateInit(Z1, default)),
-    ?m(L when is_list(L), zlib:deflate(Z1, <<1,1,1,1,1,1,1,1,1>>, none)),
-    ?m(ok, zlib:deflateParams(Z1, best_compression, huffman_only)),
-    ?m(L when is_list(L), zlib:deflate(Z1, <<1,1,1,1,1,1,1,1,1>>, sync)),
-    ?m(ok, zlib:close(Z1)).
+
+    ApiTest =
+        fun(Level, Strategy) ->
+            ?m(ok, zlib:deflateParams(Z1, Level, Strategy)),
+            ?m(ok, zlib:deflateReset(Z1))
+        end,
+
+    [ ApiTest(Level, Strategy) || Level <- Levels, Strategy <- Strategies ],
+
+    ?m(ok, zlib:close(Z1)),
+
+    FlushTest =
+        fun FlushTest(Size, Level, Strategy) ->
+            Z = zlib:open(),
+            ok = zlib:deflateInit(Z, default),
+            Data = gen_determ_rand_bytes(Size),
+            case zlib:deflate(Z, Data, none) of
+                [<<120, 156>>] ->
+                    %% All data is present in the internal zlib state, and will
+                    %% be flushed on deflateParams.
+
+                    ok = zlib:deflateParams(Z, Level, Strategy),
+                    Compressed = [<<120, 156>>, zlib:deflate(Z, <<>>, finish)],
+                    Data = zlib:uncompress(Compressed),
+                    zlib:close(Z),
+
+                    FlushTest(Size + (1 bsl 10), Level, Strategy);
+                _Other ->
+                    ok
+            end
+        end,
+
+    [ FlushTest(1, Level, Strategy) || Level <- Levels, Strategy <- Strategies ],
+
+    ok.
 
 %% Test deflate.
 api_deflate(Config) when is_list(Config) ->
@@ -762,13 +796,13 @@ zip_usage({run,ZIP,ORIG}) ->
 
     ?m(ok, zlib:deflateInit(Z, default, deflated, -15, 8, default)),
     C2 = zlib:deflate(Z, ORIG, finish),
-    ?m(true, C1 == list_to_binary(C2)),
+    ?m(ORIG, zlib:unzip(C2)),
     ?m(ok, zlib:deflateEnd(Z)),
 
     ?m(ok, zlib:deflateInit(Z, none, deflated, -15, 8, filtered)),
     ?m(ok, zlib:deflateParams(Z, default, default)),
     C3 = zlib:deflate(Z, ORIG, finish),
-    ?m(true, C1 == list_to_binary(C3)),
+    ?m(ORIG, zlib:unzip(C3)),
     ?m(ok, zlib:deflateEnd(Z)),
 
     ok = zlib:close(Z),