int FUZ_test(U32 seed, int nbCycles, int startCycle, double compressibility) {
        unsigned long long bytes = 0;
        unsigned long long cbytes = 0;
        unsigned long long hcbytes = 0;
        unsigned long long ccbytes = 0;
        void* CNBuffer;
        char* compressedBuffer;
        char* decodedBuffer;
#       define FUZ_max   LZ4_COMPRESSBOUND(LEN)
        unsigned int randState=seed;
        int ret, cycleNb;
#       define FUZ_CHECKTEST(cond, ...) if (cond) { printf("Test %i : ", testNb); printf(__VA_ARGS__); \
                                        printf(" (seed %u, cycle %i) \n", seed, cycleNb); goto _output_error; }
#       define FUZ_DISPLAYTEST          { testNb++; ((displayLevel<3) || no_prompt) ? 0 : printf("%2i\b\b", testNb); if (displayLevel==4) fflush(stdout); }
        void* stateLZ4   = malloc(LZ4_sizeofState());
        void* stateLZ4HC = malloc(LZ4_sizeofStateHC());
        void* LZ4continue;
        LZ4_stream_t LZ4dict;
        U32 crcOrig, crcCheck;
        int displayRefresh;


        // init
        memset(&LZ4dict, 0, sizeof(LZ4dict));

        // Create compressible test buffer
        CNBuffer = malloc(COMPRESSIBLE_NOISE_LENGTH);
        FUZ_fillCompressibleNoiseBuffer(CNBuffer, COMPRESSIBLE_NOISE_LENGTH, compressibility, &randState);
        compressedBuffer = malloc(LZ4_compressBound(FUZ_MAX_BLOCK_SIZE));
        decodedBuffer = malloc(FUZ_MAX_DICT_SIZE + FUZ_MAX_BLOCK_SIZE);

        // display refresh rate
        switch(displayLevel)
        {
        case 0: displayRefresh = nbCycles+1; break;
        case 1: displayRefresh=FUZ_MAX(1, nbCycles / 100); break;
        case 2: displayRefresh=89; break;
        default : displayRefresh=1;
        }

        // move to startCycle
        for (cycleNb = 0; cycleNb < startCycle; cycleNb++)
        {
            // synd rand & dict
            int dictSize, blockSize, blockStart;
            char* dict;
            char* block;

            blockSize  = FUZ_rand(&randState) % FUZ_MAX_BLOCK_SIZE;
            blockStart = FUZ_rand(&randState) % (COMPRESSIBLE_NOISE_LENGTH - blockSize);
            dictSize   = FUZ_rand(&randState) % FUZ_MAX_DICT_SIZE;
            if (dictSize > blockStart) dictSize = blockStart;
            block = ((char*)CNBuffer) + blockStart;
            dict = block - dictSize;
            LZ4_loadDict(&LZ4dict, dict, dictSize);
            LZ4_compress_continue(&LZ4dict, block, compressedBuffer, blockSize);
            LZ4_loadDict(&LZ4dict, dict, dictSize);
            LZ4_compress_continue(&LZ4dict, block, compressedBuffer, blockSize);
            LZ4_loadDict(&LZ4dict, dict, dictSize);
            LZ4_compress_continue(&LZ4dict, block, compressedBuffer, blockSize);
        }

        // Test loop
        for (cycleNb = startCycle; cycleNb < nbCycles; cycleNb++)
        {
            int testNb = 0;
            char* dict;
            char* block;
            int dictSize, blockSize, blockStart, compressedSize, HCcompressedSize;
            int blockContinueCompressedSize;

            if ((cycleNb%displayRefresh) == 0)
            {
                printf("\r%7i /%7i   - ", cycleNb, nbCycles);
                fflush(stdout);
            }

            // Select block to test
            blockSize  = FUZ_rand(&randState) % FUZ_MAX_BLOCK_SIZE;
            blockStart = FUZ_rand(&randState) % (COMPRESSIBLE_NOISE_LENGTH - blockSize);
            dictSize   = FUZ_rand(&randState) % FUZ_MAX_DICT_SIZE;
            if (dictSize > blockStart) dictSize = blockStart;
            block = ((char*)CNBuffer) + blockStart;
            dict = block - dictSize;

            /* Compression tests */

            // Test compression HC
            FUZ_DISPLAYTEST;
            ret = LZ4_compressHC(block, compressedBuffer, blockSize);
            FUZ_CHECKTEST(ret==0, "LZ4_compressHC() failed");
            HCcompressedSize = ret;

            // Test compression HC using external state
            FUZ_DISPLAYTEST;
            ret = LZ4_compressHC_withStateHC(stateLZ4HC, block, compressedBuffer, blockSize);
            FUZ_CHECKTEST(ret==0, "LZ4_compressHC_withStateHC() failed");

            // Test compression using external state
            FUZ_DISPLAYTEST;
            ret = LZ4_compress_withState(stateLZ4, block, compressedBuffer, blockSize);
            FUZ_CHECKTEST(ret==0, "LZ4_compress_withState() failed");

            // Test compression
            FUZ_DISPLAYTEST;
            ret = LZ4_compress(block, compressedBuffer, blockSize);
            FUZ_CHECKTEST(ret==0, "LZ4_compress() failed");
            compressedSize = ret;

            /* Decompression tests */

            crcOrig = XXH32(block, blockSize, 0);

            // Test decoding with output size being exactly what's necessary => must work
            FUZ_DISPLAYTEST;
            ret = LZ4_decompress_fast(compressedBuffer, decodedBuffer, blockSize);
            FUZ_CHECKTEST(ret<0, "LZ4_decompress_fast failed despite correct space");
            FUZ_CHECKTEST(ret!=compressedSize, "LZ4_decompress_fast failed : did not fully read compressed data");
            crcCheck = XXH32(decodedBuffer, blockSize, 0);
            FUZ_CHECKTEST(crcCheck!=crcOrig, "LZ4_decompress_fast corrupted decoded data");

            // Test decoding with one byte missing => must fail
            FUZ_DISPLAYTEST;
            decodedBuffer[blockSize-1] = 0;
            ret = LZ4_decompress_fast(compressedBuffer, decodedBuffer, blockSize-1);
            FUZ_CHECKTEST(ret>=0, "LZ4_decompress_fast should have failed, due to Output Size being too small");
            FUZ_CHECKTEST(decodedBuffer[blockSize-1], "LZ4_decompress_fast overrun specified output buffer");

            // Test decoding with one byte too much => must fail
            FUZ_DISPLAYTEST;
            ret = LZ4_decompress_fast(compressedBuffer, decodedBuffer, blockSize+1);
            FUZ_CHECKTEST(ret>=0, "LZ4_decompress_fast should have failed, due to Output Size being too large");

            // Test decoding with output size exactly what's necessary => must work
            FUZ_DISPLAYTEST;
            decodedBuffer[blockSize] = 0;
            ret = LZ4_decompress_safe(compressedBuffer, decodedBuffer, compressedSize, blockSize);
            FUZ_CHECKTEST(ret<0, "LZ4_decompress_safe failed despite sufficient space");
            FUZ_CHECKTEST(ret!=blockSize, "LZ4_decompress_safe did not regenerate original data");
            FUZ_CHECKTEST(decodedBuffer[blockSize], "LZ4_decompress_safe overrun specified output buffer size");
            crcCheck = XXH32(decodedBuffer, blockSize, 0);
            FUZ_CHECKTEST(crcCheck!=crcOrig, "LZ4_decompress_safe corrupted decoded data");

            // Test decoding with more than enough output size => must work
            FUZ_DISPLAYTEST;
            decodedBuffer[blockSize] = 0;
            decodedBuffer[blockSize+1] = 0;
            ret = LZ4_decompress_safe(compressedBuffer, decodedBuffer, compressedSize, blockSize+1);
            FUZ_CHECKTEST(ret<0, "LZ4_decompress_safe failed despite amply sufficient space");
            FUZ_CHECKTEST(ret!=blockSize, "LZ4_decompress_safe did not regenerate original data");
            //FUZ_CHECKTEST(decodedBuffer[blockSize], "LZ4_decompress_safe wrote more than (unknown) target size");   // well, is that an issue ?
            FUZ_CHECKTEST(decodedBuffer[blockSize+1], "LZ4_decompress_safe overrun specified output buffer size");
            crcCheck = XXH32(decodedBuffer, blockSize, 0);
            FUZ_CHECKTEST(crcCheck!=crcOrig, "LZ4_decompress_safe corrupted decoded data");

            // Test decoding with output size being one byte too short => must fail
            FUZ_DISPLAYTEST;
            decodedBuffer[blockSize-1] = 0;
            ret = LZ4_decompress_safe(compressedBuffer, decodedBuffer, compressedSize, blockSize-1);
            FUZ_CHECKTEST(ret>=0, "LZ4_decompress_safe should have failed, due to Output Size being one byte too short");
            FUZ_CHECKTEST(decodedBuffer[blockSize-1], "LZ4_decompress_safe overrun specified output buffer size");

            // Test decoding with output size being 10 bytes too short => must fail
            FUZ_DISPLAYTEST;
            if (blockSize>10)
            {
                decodedBuffer[blockSize-10] = 0;
                ret = LZ4_decompress_safe(compressedBuffer, decodedBuffer, compressedSize, blockSize-10);
                FUZ_CHECKTEST(ret>=0, "LZ4_decompress_safe should have failed, due to Output Size being 10 bytes too short");
                FUZ_CHECKTEST(decodedBuffer[blockSize-10], "LZ4_decompress_safe overrun specified output buffer size");
            }

            // Test decoding with input size being one byte too short => must fail
            FUZ_DISPLAYTEST;
            ret = LZ4_decompress_safe(compressedBuffer, decodedBuffer, compressedSize-1, blockSize);
            FUZ_CHECKTEST(ret>=0, "LZ4_decompress_safe should have failed, due to input size being one byte too short (blockSize=%i, ret=%i, compressedSize=%i)", blockSize, ret, compressedSize);

            // Test decoding with input size being one byte too large => must fail
            FUZ_DISPLAYTEST;
            decodedBuffer[blockSize] = 0;
            ret = LZ4_decompress_safe(compressedBuffer, decodedBuffer, compressedSize+1, blockSize);
            FUZ_CHECKTEST(ret>=0, "LZ4_decompress_safe should have failed, due to input size being too large");
            FUZ_CHECKTEST(decodedBuffer[blockSize], "LZ4_decompress_safe overrun specified output buffer size");

            // Test partial decoding with target output size being max/2 => must work
            FUZ_DISPLAYTEST;
            ret = LZ4_decompress_safe_partial(compressedBuffer, decodedBuffer, compressedSize, blockSize/2, blockSize);
            FUZ_CHECKTEST(ret<0, "LZ4_decompress_safe_partial failed despite sufficient space");

            // Test partial decoding with target output size being just below max => must work
            FUZ_DISPLAYTEST;
            ret = LZ4_decompress_safe_partial(compressedBuffer, decodedBuffer, compressedSize, blockSize-3, blockSize);
            FUZ_CHECKTEST(ret<0, "LZ4_decompress_safe_partial failed despite sufficient space");

            /* Test Compression with limited output size */

            // Test compression with output size being exactly what's necessary (should work)
            FUZ_DISPLAYTEST;
            ret = LZ4_compress_limitedOutput(block, compressedBuffer, blockSize, compressedSize);
            FUZ_CHECKTEST(ret==0, "LZ4_compress_limitedOutput() failed despite sufficient space");

            // Test compression with output size being exactly what's necessary and external state (should work)
            FUZ_DISPLAYTEST;
            ret = LZ4_compress_limitedOutput_withState(stateLZ4, block, compressedBuffer, blockSize, compressedSize);
            FUZ_CHECKTEST(ret==0, "LZ4_compress_limitedOutput_withState() failed despite sufficient space");

            // Test HC compression with output size being exactly what's necessary (should work)
            FUZ_DISPLAYTEST;
            ret = LZ4_compressHC_limitedOutput(block, compressedBuffer, blockSize, HCcompressedSize);
            FUZ_CHECKTEST(ret==0, "LZ4_compressHC_limitedOutput() failed despite sufficient space");

            // Test HC compression with output size being exactly what's necessary (should work)
            FUZ_DISPLAYTEST;
            ret = LZ4_compressHC_limitedOutput_withStateHC(stateLZ4HC, block, compressedBuffer, blockSize, HCcompressedSize);
            FUZ_CHECKTEST(ret==0, "LZ4_compressHC_limitedOutput_withStateHC() failed despite sufficient space");

            // Test compression with just one missing byte into output buffer => must fail
            FUZ_DISPLAYTEST;
            compressedBuffer[compressedSize-1] = 0;
            ret = LZ4_compress_limitedOutput(block, compressedBuffer, blockSize, compressedSize-1);
            FUZ_CHECKTEST(ret, "LZ4_compress_limitedOutput should have failed (output buffer too small by 1 byte)");
            FUZ_CHECKTEST(compressedBuffer[compressedSize-1], "LZ4_compress_limitedOutput overran output buffer")

            // Test HC compression with just one missing byte into output buffer => must fail
            FUZ_DISPLAYTEST;
            compressedBuffer[compressedSize-1] = 0;
            ret = LZ4_compressHC_limitedOutput(block, compressedBuffer, blockSize, HCcompressedSize-1);
            FUZ_CHECKTEST(ret, "LZ4_compressHC_limitedOutput should have failed (output buffer too small by 1 byte)");
            FUZ_CHECKTEST(compressedBuffer[compressedSize-1], "LZ4_compressHC_limitedOutput overran output buffer")

            /* Dictionary tests */

            // Compress using dictionary
            FUZ_DISPLAYTEST;
            LZ4continue = LZ4_create (dict);
            LZ4_compress_continue (LZ4continue, dict, compressedBuffer, dictSize);   // Just to fill hash tables
            blockContinueCompressedSize = LZ4_compress_continue (LZ4continue, block, compressedBuffer, blockSize);
            FUZ_CHECKTEST(blockContinueCompressedSize==0, "LZ4_compress_continue failed");
            LZ4_free (LZ4continue);

            // Decompress with dictionary as prefix
            FUZ_DISPLAYTEST;
            memcpy(decodedBuffer, dict, dictSize);
            ret = LZ4_decompress_fast_withPrefix64k(compressedBuffer, decodedBuffer+dictSize, blockSize);
            FUZ_CHECKTEST(ret!=blockContinueCompressedSize, "LZ4_decompress_fast_withPrefix64k did not read all compressed block input");
            crcCheck = XXH32(decodedBuffer+dictSize, blockSize, 0);
            if (crcCheck!=crcOrig)
            {
                int i=0;
                while (block[i]==decodedBuffer[i]) i++;
                printf("Wrong Byte at position %i/%i\n", i, blockSize);

            }
            FUZ_CHECKTEST(crcCheck!=crcOrig, "LZ4_decompress_fast_withPrefix64k corrupted decoded data (dict %i)", dictSize);

            FUZ_DISPLAYTEST;
            ret = LZ4_decompress_safe_withPrefix64k(compressedBuffer, decodedBuffer+dictSize, blockContinueCompressedSize, blockSize);
            FUZ_CHECKTEST(ret!=blockSize, "LZ4_decompress_safe_withPrefix64k did not regenerate original data");
            crcCheck = XXH32(decodedBuffer+dictSize, blockSize, 0);
            FUZ_CHECKTEST(crcCheck!=crcOrig, "LZ4_decompress_safe_withPrefix64k corrupted decoded data");

            // Compress using External dictionary
            FUZ_DISPLAYTEST;
            dict -= 9;   // Separation, so it is an ExtDict
            if (dict < (char*)CNBuffer) dict = (char*)CNBuffer;
            LZ4_loadDict(&LZ4dict, dict, dictSize);
            blockContinueCompressedSize = LZ4_compress_continue(&LZ4dict, block, compressedBuffer, blockSize);
            FUZ_CHECKTEST(blockContinueCompressedSize==0, "LZ4_compress_continue failed");

            FUZ_DISPLAYTEST;
            LZ4_loadDict(&LZ4dict, dict, dictSize);
            ret = LZ4_compress_limitedOutput_continue(&LZ4dict, block, compressedBuffer, blockSize, blockContinueCompressedSize-1);
            FUZ_CHECKTEST(ret>0, "LZ4_compress_limitedOutput_continue using ExtDict should fail : one missing byte for output buffer");

            FUZ_DISPLAYTEST;
            LZ4_loadDict(&LZ4dict, dict, dictSize);
            ret = LZ4_compress_limitedOutput_continue(&LZ4dict, block, compressedBuffer, blockSize, blockContinueCompressedSize);
            FUZ_CHECKTEST(ret!=blockContinueCompressedSize, "LZ4_compress_limitedOutput_compressed size is different (%i != %i)", ret, blockContinueCompressedSize);
            FUZ_CHECKTEST(ret<=0, "LZ4_compress_limitedOutput_continue should work : enough size available within output buffer");

            // Decompress with dictionary as external
            FUZ_DISPLAYTEST;
            decodedBuffer[blockSize] = 0;
            ret = LZ4_decompress_fast_usingDict(compressedBuffer, decodedBuffer, blockSize, dict, dictSize);
            FUZ_CHECKTEST(ret!=blockContinueCompressedSize, "LZ4_decompress_fast_usingDict did not read all compressed block input");
            FUZ_CHECKTEST(decodedBuffer[blockSize], "LZ4_decompress_fast_usingDict overrun specified output buffer size")
            crcCheck = XXH32(decodedBuffer, blockSize, 0);
            if (crcCheck!=crcOrig)
            {
                int i=0;
                while (block[i]==decodedBuffer[i]) i++;
                printf("Wrong Byte at position %i/%i\n", i, blockSize);

            }
            FUZ_CHECKTEST(crcCheck!=crcOrig, "LZ4_decompress_fast_usingDict corrupted decoded data (dict %i)", dictSize);

            FUZ_DISPLAYTEST;
            decodedBuffer[blockSize] = 0;
            ret = LZ4_decompress_safe_usingDict(compressedBuffer, decodedBuffer, blockContinueCompressedSize, blockSize, dict, dictSize);
            FUZ_CHECKTEST(ret!=blockSize, "LZ4_decompress_safe_usingDict did not regenerate original data");
            FUZ_CHECKTEST(decodedBuffer[blockSize], "LZ4_decompress_safe_usingDict overrun specified output buffer size")
            crcCheck = XXH32(decodedBuffer, blockSize, 0);
            FUZ_CHECKTEST(crcCheck!=crcOrig, "LZ4_decompress_safe_usingDict corrupted decoded data");

            FUZ_DISPLAYTEST;
            decodedBuffer[blockSize-1] = 0;
            ret = LZ4_decompress_fast_usingDict(compressedBuffer, decodedBuffer, blockSize-1, dict, dictSize);
            FUZ_CHECKTEST(ret>=0, "LZ4_decompress_fast_withDict should have failed : wrong original size (-1 byte)");
            FUZ_CHECKTEST(decodedBuffer[blockSize-1], "LZ4_decompress_fast_usingDict overrun specified output buffer size");

            FUZ_DISPLAYTEST;
            decodedBuffer[blockSize-1] = 0;
            ret = LZ4_decompress_safe_usingDict(compressedBuffer, decodedBuffer, blockContinueCompressedSize, blockSize-1, dict, dictSize);
            FUZ_CHECKTEST(ret>=0, "LZ4_decompress_safe_usingDict should have failed : not enough output size (-1 byte)");
            FUZ_CHECKTEST(decodedBuffer[blockSize-1], "LZ4_decompress_safe_usingDict overrun specified output buffer size");

            FUZ_DISPLAYTEST;
            if (blockSize > 10)
            {
                decodedBuffer[blockSize-10] = 0;
                ret = LZ4_decompress_safe_usingDict(compressedBuffer, decodedBuffer, blockContinueCompressedSize, blockSize-10, dict, dictSize);
                FUZ_CHECKTEST(ret>=0, "LZ4_decompress_safe_usingDict should have failed : output buffer too small (-10 byte)");
                FUZ_CHECKTEST(decodedBuffer[blockSize-10], "LZ4_decompress_safe_usingDict overrun specified output buffer size (-10 byte) (blockSize=%i)", blockSize);
            }


            // Fill stats
            bytes += blockSize;
            cbytes += compressedSize;
            hcbytes += HCcompressedSize;
            ccbytes += blockContinueCompressedSize;
        }

        printf("\r%7i /%7i   - ", cycleNb, nbCycles);
        printf("all tests completed successfully \n");
        printf("compression ratio: %0.3f%%\n", (double)cbytes/bytes*100);
        printf("HC compression ratio: %0.3f%%\n", (double)hcbytes/bytes*100);
        printf("ratio with dict: %0.3f%%\n", (double)ccbytes/bytes*100);

        // unalloc
        if(!no_prompt) getchar();
        free(CNBuffer);
        free(compressedBuffer);
        free(decodedBuffer);
        free(stateLZ4);
        free(stateLZ4HC);
        return 0;

_output_error:
        if(!no_prompt) getchar();
        free(CNBuffer);
        free(compressedBuffer);
        free(decodedBuffer);
        free(stateLZ4);
        free(stateLZ4HC);
        return 1;
}