test zstd compression (#129)

* add zstd compression tests

src/streamers.jl

@@ -87,7 +87,7 @@ function Streamers(io)
         elseif cname == "XZ"
             IOBuffer(transcode(XzDecompressor, compressedbytes))
         elseif cname == "ZS"
-            IOBuffer(transcode(ZstdDecompressor, io))
+            IOBuffer(transcode(ZstdDecompressor, compressedbytes))
         elseif cname == "L4"
             IOBuffer(lz4_decompress(compressedbytes[9:end], tkey.fObjlen))
         else

test/runtests.jl

@@ -183,6 +183,11 @@ end
     @test 100000 == length(arr)
     @test [0.0, 1.0588236, 2.1176472, 3.1764705, 4.2352943] ≈ arr[1:5] atol=1e-7
     close(rootfile)
+
+    rootfile = ROOTFile(joinpath(SAMPLES_DIR, "tree_with_int_array_zstd.root"))
+    arr = collect(rootfile["t1/a"])
+    @test arr == 0:99
+    close(rootfile)
 end
 
 @testset "ROOTDirectoryHeader" begin

test/samples/zstd_tree.py

@@ -0,0 +1,18 @@
+# Run this with a newer version of ROOT
+# Otherwise zstd isn't available and the
+# 505 will fall back to zlib
+from ROOT import TFile, TTree
+from array import array
+
+f = TFile('tree_with_int_array_zstd.root', 'recreate', "filename", 505)
+t = TTree('t1', '')
+
+n = array('i', [0])
+t.Branch('a', n, 'a/I')
+
+for i in range(100):
+    n[0] = i
+    t.Fill()
+
+f.Write()
+f.Close()