diff -r 21274e5950af -r a1f4cb076d2f src/server/test/writer.c
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/server/test/writer.c	Sat Sep 24 16:26:10 2022 +0200
@@ -0,0 +1,151 @@
+/*
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
+ *
+ * Copyright 2020 Olaf Wintermann. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ *   1. Redistributions of source code must retain the above copyright
+ *      notice, this list of conditions and the following disclaimer.
+ *
+ *   2. Redistributions in binary form must reproduce the above copyright
+ *      notice, this list of conditions and the following disclaimer in the
+ *      documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "../util/writer.h"
+
+#include <ucx/buffer.h>
+
+#include "writer.h"
+#include "testutils.h"
+
+UCX_TEST(test_writer_putc) {
+    Session *sn = testutil_session();
+    TestIOStream *st = testutil_iostream(2048, TRUE);
+    UcxBuffer *buf = st->buf;
+    
+    UCX_TEST_BEGIN;
+    
+    Writer writer;
+    char wbuf[1024];
+    writer_init(&writer, st, wbuf, 4);
+    Writer *out = &writer;
+    
+    writer_putc(out, 'a');
+    UCX_TEST_ASSERT(wbuf[0] == 'a', "1: wrong char at pos 0");
+    UCX_TEST_ASSERT(writer.pos == 1, "1: wrong pos");
+    
+    writer_putc(out, 'b');
+    UCX_TEST_ASSERT(wbuf[1] == 'b', "2: wrong char at pos 1");
+    UCX_TEST_ASSERT(writer.pos == 2, "2: wrong pos");
+    
+    writer_putc(out, 'c');
+    writer_putc(out, 'd');
+    UCX_TEST_ASSERT(wbuf[2] == 'c', "3: wrong char at pos 2");
+    UCX_TEST_ASSERT(wbuf[3] == 'd', "4: wrong char at pos 3");
+    
+    writer_putc(out, 'f'); // should flush the buffer
+    UCX_TEST_ASSERT(wbuf[0] == 'f', "5: wrong char at pos 0");
+    UCX_TEST_ASSERT(writer.pos == 1, "5: wrong pos");
+    UCX_TEST_ASSERT(buf->space[0] == 'a', "5: wrong char at UcxBuffer pos 0");
+    UCX_TEST_ASSERT(buf->space[1] == 'b', "5: wrong char at UcxBuffer pos 1");
+    UCX_TEST_ASSERT(buf->pos == 4, "5: wrong UcxBuffer pos");    
+    
+    UCX_TEST_END;
+    testutil_iostream_destroy(st);
+    testutil_destroy_session(sn);
+}
+
+UCX_TEST(test_writer_flush) {
+    Session *sn = testutil_session();
+    TestIOStream *st = testutil_iostream(2048, TRUE);
+    UcxBuffer *buf = st->buf;
+    
+    UCX_TEST_BEGIN;
+    
+    Writer writer;
+    char wbuf[1024];
+    writer_init(&writer, st, wbuf, 4);
+    Writer *out = &writer;
+    
+    writer_putc(out, 'a');
+    UCX_TEST_ASSERT(wbuf[0] == 'a', "1: wrong char at pos 0");
+    UCX_TEST_ASSERT(writer.pos == 1, "1: wrong pos");
+    
+    writer_flush(out);
+    UCX_TEST_ASSERT(writer.pos == 0, "wrong pos after flush");
+    UCX_TEST_ASSERT(buf->space[0] == 'a', "wrong UcxBuffer content");
+    UCX_TEST_ASSERT(buf->pos == 1, "wrong UcxBuffer pos");
+    
+    writer_putc(out, 'b');
+    UCX_TEST_ASSERT(wbuf[0] == 'b', "2: wrong char at pos 0");
+    UCX_TEST_ASSERT(writer.pos == 1, "2: wrong pos");
+    
+    UCX_TEST_END;
+    testutil_iostream_destroy(st);
+    testutil_destroy_session(sn);
+}
+
+UCX_TEST(test_writer_put) {
+    Session *sn = testutil_session();
+    TestIOStream *st = testutil_iostream(2048, TRUE);
+    UcxBuffer *buf = st->buf;
+    
+    UCX_TEST_BEGIN;
+    
+    Writer writer;
+    char wbuf[1024];
+    writer_init(&writer, st, wbuf, 8);
+    Writer *out = &writer;
+    
+    writer_put(out, "abcd", 4);
+    UCX_TEST_ASSERT(!memcmp(wbuf, "abcd", 4), "1: wrong content");
+    UCX_TEST_ASSERT(writer.pos == 4, "1: wrong pos");
+    
+    writer_put(out, "efgh", 4);
+    UCX_TEST_ASSERT(!memcmp(wbuf, "abcdefgh", 8), "2: wrong content");
+    UCX_TEST_ASSERT(writer.pos == 8, "2: wrong pos");
+    
+    writer_put(out, "1234", 4);
+    UCX_TEST_ASSERT(!memcmp(wbuf, "1234", 4), "3: wrong content");
+    UCX_TEST_ASSERT(writer.pos == 4, "3: wrong pos");
+    UCX_TEST_ASSERT(!memcmp(buf->space, "abcdefgh", 8), "3: wrong UcxBuffer content");
+    UCX_TEST_ASSERT(buf->pos == 8, "3: wrong UcxBuffer pos");
+    
+    writer_put(out, "5678xx", 6);
+    UCX_TEST_ASSERT(!memcmp(wbuf, "xx", 2), "4: wrong content");
+    UCX_TEST_ASSERT(writer.pos == 2, "4: wrong pos");
+    UCX_TEST_ASSERT(!memcmp(buf->space, "abcdefgh12345678", 16), "4: wrong UcxBuffer content");
+    UCX_TEST_ASSERT(buf->pos == 16, "4: wrong UcxBuffer pos");
+    
+    writer_puts(out, S("345678abcdefgh12345678end."));
+    UCX_TEST_ASSERT(!memcmp(wbuf, "end.", 4), "5: wrong content");
+    UCX_TEST_ASSERT(writer.pos == 4, "5: wrong pos");
+    UCX_TEST_ASSERT(!memcmp(
+            buf->space,
+            "abcdefgh12345678xx345678abcdefgh12345678",
+            40),
+            "5: wrong UcxBuffer content");
+    UCX_TEST_ASSERT(buf->pos == 40, "5: wrong UcxBuffer pos");
+    
+    UCX_TEST_END;
+    testutil_iostream_destroy(st);
+    testutil_destroy_session(sn);
+}