diff --git a/tests/Makefile b/tests/Makefile
index f7b39c8..71f6c0f 100644
--- a/tests/Makefile
+++ b/tests/Makefile
@@ -2,7 +2,7 @@ CC=gcc
 CFLAGS=-fPIC -Wall -Wextra -ggdb -gdwarf-2 -g3
 CGREEN_RUNNER=cgreen-runner
 
-TESTS=resize rdp xwin utils parse_geometry
+TESTS=resize rdp xwin utils parse_geometry mcs
 
 
 RDP_MOCKS=ui_mock.o bitmap_mock.o secure_mock.o ssl_mock.o mppc_mock.o \
@@ -23,6 +23,8 @@ PARSE_MOCKS=ui_mock.o rdpdr_mock.o rdpedisp_mock.o ssl_mock.o ctrl_mock.o secure
 	tcp_mock.o dvc_mock.o rdp_mock.o cache_mock.o cliprdr_mock.o disk_mock.o lspci_mock.o \
 	parallel_mock.o printer_mock.o serial_mock.o xkeymap_mock.o utils_mock.o xwin_mock.o
 
+MCS_MOCKS=utils_mock.o secure_mock.o iso_mock.o
+
 all: test
 
 .PHONY: test
@@ -49,6 +51,12 @@ resize: resize_test.o $(RESIZE_MOCKS)
 parse_geometry: parse_geometry_test.o $(PARSE_MOCKS) ../rdesktop.c
 	$(CC) $(CFLAGS) -shared -lcgreen -o $@ parse_geometry_test.o $(PARSE_MOCKS)
 
+mcs: mcs_test.o $(MCS_MOCKS) stream.o
+	$(CC) $(CFLAGS) -shared -lcgreen -o $@ $^
+
+stream.o: ../stream.c
+	$(CC) $(CFLAGS) -c -o $@ $^
+
 .PHONY: clean
 clean:
 	rm -f $(TESTS) *_mock.o *_test.o
diff --git a/tests/iso_mock.c b/tests/iso_mock.c
new file mode 100644
index 0000000..5280443
--- /dev/null
+++ b/tests/iso_mock.c
@@ -0,0 +1,37 @@
+#include <cgreen/mocks.h>
+#include "../rdesktop.h"
+
+RD_BOOL
+iso_connect(char *server, char *username, char *domain, char *password,
+	    RD_BOOL reconnect, uint32 * selected_protocol)
+{
+  return (RD_BOOL) mock(server, username, domain, password, reconnect, selected_protocol);
+}
+
+
+void
+iso_disconnect(void)
+{
+  mock();
+}
+
+void iso_send(STREAM stream)
+{
+  mock(stream->data);
+}
+
+STREAM iso_recv(uint8 *rdpver)
+{
+  return (STREAM)mock(rdpver);
+}
+
+void
+iso_reset_state(void)
+{
+  mock();
+}
+
+STREAM iso_init(int length)
+{
+  return (STREAM)mock(length);
+}
diff --git a/tests/mcs_test.c b/tests/mcs_test.c
new file mode 100644
index 0000000..5799602
--- /dev/null
+++ b/tests/mcs_test.c
@@ -0,0 +1,83 @@
+#include <cgreen/cgreen.h>
+#include <cgreen/mocks.h>
+#include "../rdesktop.h"
+
+/* Boilerplate */
+Describe(MCS);
+BeforeEach(MCS) {};
+AfterEach(MCS) {};
+
+char g_codepage[16];
+VCHANNEL g_channels[1];
+unsigned int g_num_channels;
+
+#include "../asn.c"
+#include "../mcs.c"
+#include "../stream.h"
+
+/* malloc; exit if out of memory */
+void *
+xmalloc(int size)
+{
+	void *mem = malloc(size);
+	if (mem == NULL)
+	{
+		logger(Core, Error, "xmalloc, failed to allocate %d bytes", size);
+		exit(EX_UNAVAILABLE);
+	}
+	return mem;
+}
+
+/* realloc; exit if out of memory */
+void *
+xrealloc(void *oldmem, size_t size)
+{
+	void *mem;
+
+	if (size == 0)
+		size = 1;
+	mem = realloc(oldmem, size);
+	if (mem == NULL)
+	{
+		logger(Core, Error, "xrealloc, failed to reallocate %ld bytes", size);
+		exit(EX_UNAVAILABLE);
+	}
+	return mem;
+}
+
+/* free */
+void
+xfree(void *mem)
+{
+	free(mem);
+}
+
+static struct stream  *stream_new(size_t size) {
+  struct stream  *s;
+  s = malloc(sizeof(struct stream));
+  memset(s, 0, sizeof(struct stream));
+  s_realloc(s, size);
+  s_reset(s);
+  return(s);
+}
+
+
+/* Test function */
+Ensure(MCS, should_produce_valid_packet_for_McsSendCJrq)
+{
+  uint16 chan_id;
+  uint8_t content[] = {0x38, 0x00, 0x2A, 0x00, 0x0D};
+
+  struct stream *s;
+  s = stream_new(5);
+
+  chan_id = 13;
+  g_mcs_userid = 42;
+
+  expect(logger);
+  expect(iso_init, will_return(s));
+  expect(iso_send, when(stream->data, is_equal_to_contents_of(content, sizeof(content))));
+
+  mcs_send_cjrq(chan_id);
+  s_free(s);
+}
diff --git a/tests/secure_mock.c b/tests/secure_mock.c
index 8d19c7d..69390e5 100644
--- a/tests/secure_mock.c
+++ b/tests/secure_mock.c
@@ -42,3 +42,10 @@ sec_hash_to_string(char *out, int out_size, uint8 * in, int in_size)
 {
   mock(out, out_size, in, in_size);
 }
+
+
+void
+sec_process_mcs_data(STREAM s)
+{
+  mock(s);
+}