diff --git a/core-buffer/test/test_WriterH5Writer.cpp b/core-buffer/test/test_WriterH5Writer.cpp
index f3f02e0..103958e 100644
--- a/core-buffer/test/test_WriterH5Writer.cpp
+++ b/core-buffer/test/test_WriterH5Writer.cpp
@@ -1,10 +1,8 @@
 
 #include "WriterH5Writer.hpp"
 #include "gtest/gtest.h"
+#include "bitshuffle/bitshuffle.h"
 
-extern "C" {
-    #include <bitshuffle/bshuf_h5filter.h>
-}
 
 using namespace core_buffer;
 
@@ -13,12 +11,70 @@ TEST(WriterH5Writer, basic_interaction)
     size_t n_modules = 2;
     size_t n_frames = 5;
 
-//    auto data = make_unique<char[]>(n_modules*MODULE_N_BYTES);
-//    auto metadata = make_shared<ImageMetadata>();
-//
-//    WriterH5Writer writer("ignore.h5", n_frames, n_modules);
-//    writer.write(metadata.get(), data.get());
-//    writer.close_file();
+    auto data = make_unique<char[]>(n_modules*MODULE_N_BYTES);
+    auto metadata = make_shared<ImageMetadata>();
 
-    // TODO: Write some test.
+    // Needed by writer.
+    metadata->compressed_image_size = 500;
+
+    WriterH5Writer writer("ignore.h5", n_frames, n_modules);
+    writer.write(metadata.get(), data.get());
+    writer.close_file();
+}
+
+TEST(WriterH5Writer, test_compression)
+{
+    size_t n_modules = 2;
+    size_t n_frames = 5;
+
+    auto comp_buffer_size = bshuf_compress_lz4_bound(
+            MODULE_N_PIXELS, PIXEL_N_BYTES, MODULE_N_PIXELS);
+
+    auto f_raw_buffer = make_unique<uint16_t[]>(MODULE_N_PIXELS);
+    auto f_comp_buffer = make_unique<char[]>(comp_buffer_size);
+
+    auto i_comp_buffer = make_unique<char[]>(
+            (comp_buffer_size * n_modules) + 12);
+    auto i_raw_buffer = make_unique<uint16_t[]>((MODULE_N_PIXELS * n_modules));
+
+    bshuf_write_uint64_BE(i_comp_buffer.get(),
+            MODULE_N_BYTES * n_modules);
+    bshuf_write_uint32_BE(i_comp_buffer.get() + 8,
+            MODULE_N_PIXELS * PIXEL_N_BYTES);
+
+    size_t total_compressed_size = 0;
+    for (int i_module=0; i_module<n_modules; i_module++) {
+
+        for (size_t i=0; i<MODULE_N_PIXELS; i++) {
+            f_raw_buffer[i] = (uint16_t) i_module;
+        }
+
+        auto compressed_size = bshuf_compress_lz4(
+                f_raw_buffer.get(), f_comp_buffer.get(),
+                MODULE_N_PIXELS, PIXEL_N_BYTES, MODULE_N_PIXELS);
+
+        memcpy((i_comp_buffer.get() + 12 + total_compressed_size),
+               f_comp_buffer.get(),
+               compressed_size);
+
+        total_compressed_size += compressed_size;
+    }
+
+    auto metadata = make_shared<ImageMetadata>();
+    metadata->compressed_image_size = total_compressed_size;
+
+    metadata->is_good_frame = 1;
+    metadata->frame_index = 3;
+    metadata->pulse_id = 3;
+    metadata->daq_rec = 3;
+
+    WriterH5Writer writer("ignore.h5", n_frames, n_modules);
+    writer.write(metadata.get(), i_comp_buffer.get());
+    writer.close_file();
+
+    H5::H5File reader("ignore.h5", H5F_ACC_RDONLY);
+    auto image_dataset = reader.openDataSet("image");
+    image_dataset.read(i_raw_buffer.get(), H5T_NATIVE_UINT16);
+
+    ASSERT_EQ(1, 1);
 }
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