diff --git a/tests/ipc_test.c b/tests/ipc_test.c
index ac51bf2..e6e0e17 100644
--- a/tests/ipc_test.c
+++ b/tests/ipc_test.c
@@ -1,6 +1,7 @@
 #define _POSIX_C_SOURCE 200809L
 
 #include <stdlib.h>
+#include <sys/socket.h>
 #include <unistd.h>
 #include "test.h"
 
@@ -51,3 +52,166 @@ ipc_runtime_path(struct ct *t)
 	}else
 		unsetenv("XDG_RUNTIME_DIR");
 }
+
+void
+ipc_response_pack_boundaries(struct ct *t)
+{
+	static const uchar withpre[] = { 1, 1, 0, 'A', 2, 0, 'x', 'y' };
+	static const uchar withoutpre[] = { 1, 1, 0, 'A' };
+	uchar out[Ipcmaxresp+1], field[Ipcfieldmax];
+	int n;
+
+	n = ipcpackresp(out, sizeof out, 7, "A", 1, "xy", 2, 1);
+	CT_EQ_INT(t, sizeof withpre, n);
+	CT_EQ_MEM(t, withpre, out, sizeof withpre);
+	n = ipcpackresp(out, sizeof out, 1, "A", 1, "xy", 2, 0);
+	CT_EQ_INT(t, sizeof withoutpre, n);
+	CT_EQ_MEM(t, withoutpre, out, sizeof withoutpre);
+	n = ipcpackresp(out, sizeof out, 0, nil, 0, nil, 0, 1);
+	CT_EQ_INT(t, Ipcresphdrsz + Ipclensz, n);
+
+	memset(field, 'x', sizeof field);
+	memset(out, 0xa5, sizeof out);
+	n = ipcpackresp(out, Ipcmaxresp, 1,
+		(char*)field, sizeof field, (char*)field, sizeof field, 1);
+	CT_EQ_INT(t, Ipcmaxresp, n);
+	CT_EQ_INT(t, 0, out[1]);
+	CT_EQ_INT(t, 1, out[2]);
+	CT_EQ_INT(t, 0, out[3+Ipcfieldmax]);
+	CT_EQ_INT(t, 1, out[4+Ipcfieldmax]);
+	CT_EQ_INT(t, 0xa5, out[Ipcmaxresp]);
+	CT_EQ_INT(t, -1, ipcpackresp(out, Ipcmaxresp-1, 1,
+		(char*)field, sizeof field, (char*)field, sizeof field, 1));
+	CT_EQ_INT(t, -1, ipcpackresp(out, sizeof out, 0,
+		nil, 1, nil, 0, 0));
+	CT_EQ_INT(t, -1, ipcpackresp(out, sizeof out, 0,
+		nil, 0, nil, 1, 1));
+	CT_EQ_INT(t, -1, ipcpackresp(out, sizeof out, 0,
+		(char*)field, Ipcfieldmax+1, nil, 0, 0));
+}
+
+void
+ipc_response_empty_and_preedit(struct ct *t)
+{
+	uchar first[Ipcmaxresp], second[Ipcmaxresp];
+	char commit[16], preedit[16];
+	Ipcresp resp;
+	int fd[2], nfirst, nsecond;
+
+	nfirst = ipcpackresp(first, sizeof first, 0, nil, 0, nil, 0, 0);
+	nsecond = ipcpackresp(second, sizeof second, 1,
+		"go", 2, "kana", 4, 1);
+	if(!CT_CHECK(t, nfirst > 0 && nsecond > 0))
+		return;
+	if(socketpair(AF_UNIX, SOCK_STREAM, 0, fd) < 0){
+		CT_ERRORF(t, "socketpair failed");
+		return;
+	}
+	if(CT_EQ_INT(t, 0, ipcsend(fd[0], first, nfirst)) &&
+	   CT_EQ_INT(t, 0, ipcsend(fd[0], second, nsecond)) &&
+	   CT_EQ_INT(t, 0, ipcreadresp(fd[1], 0, commit, sizeof commit,
+		nil, 0, &resp))){
+		CT_EQ_INT(t, 0, resp.eaten);
+		CT_EQ_SIZE(t, 0, resp.ncommit);
+		CT_EQ_SIZE(t, 0, resp.npreedit);
+		CT_EQ_STR(t, "", commit);
+	}
+	if(CT_EQ_INT(t, 0, ipcreadresp(fd[1], 1, commit, sizeof commit,
+		preedit, sizeof preedit, &resp))){
+		CT_EQ_INT(t, 1, resp.eaten);
+		CT_EQ_SIZE(t, 2, resp.ncommit);
+		CT_EQ_SIZE(t, 4, resp.npreedit);
+		CT_EQ_STR(t, "go", commit);
+		CT_EQ_STR(t, "kana", preedit);
+	}
+	close(fd[0]);
+	close(fd[1]);
+}
+
+void
+ipc_response_max_and_drain(struct ct *t)
+{
+	uchar first[Ipcmaxresp], second[Ipcmaxresp], field[Ipcfieldmax];
+	char commit[8], preedit[8];
+	Ipcresp resp;
+	int fd[2], nfirst, nsecond;
+
+	memset(field, 'x', sizeof field);
+	nfirst = ipcpackresp(first, sizeof first, 1,
+		(char*)field, sizeof field, (char*)field, sizeof field, 1);
+	nsecond = ipcpackresp(second, sizeof second, 0, "ok", 2, nil, 0, 0);
+	if(!CT_CHECK(t, nfirst == Ipcmaxresp && nsecond > 0))
+		return;
+	if(socketpair(AF_UNIX, SOCK_STREAM, 0, fd) < 0){
+		CT_ERRORF(t, "socketpair failed");
+		return;
+	}
+	if(CT_EQ_INT(t, 0, ipcsend(fd[0], first, nfirst)) &&
+	   CT_EQ_INT(t, 0, ipcsend(fd[0], second, nsecond)) &&
+	   CT_EQ_INT(t, 0, ipcreadresp(fd[1], 1, commit, sizeof commit,
+		preedit, sizeof preedit, &resp))){
+		CT_EQ_SIZE(t, Ipcfieldmax, resp.ncommit);
+		CT_EQ_SIZE(t, Ipcfieldmax, resp.npreedit);
+		CT_EQ_STR(t, "xxxxxxx", commit);
+		CT_EQ_STR(t, "xxxxxxx", preedit);
+	}
+	if(CT_EQ_INT(t, 0, ipcreadresp(fd[1], 0, commit, sizeof commit,
+		nil, 0, &resp)))
+		CT_EQ_STR(t, "ok", commit);
+	close(fd[0]);
+	close(fd[1]);
+}
+
+void
+ipc_response_fragmented_and_truncated(struct ct *t)
+{
+	uchar frame[Ipcmaxresp];
+	char commit[8], preedit[8];
+	Ipcresp resp;
+	int fd[2], i, n;
+
+	n = ipcpackresp(frame, sizeof frame, 1, "abc", 3, "xy", 2, 1);
+	if(!CT_CHECK(t, n > 0))
+		return;
+	if(socketpair(AF_UNIX, SOCK_STREAM, 0, fd) < 0){
+		CT_ERRORF(t, "socketpair failed");
+		return;
+	}
+	for(i = 0; i < n; i++)
+		if(ipcsend(fd[0], frame+i, 1) < 0){
+			CT_ERRORF(t, "fragment send failed");
+			break;
+		}
+	if(i == n && CT_EQ_INT(t, 0, ipcreadresp(fd[1], 1,
+		commit, sizeof commit, preedit, sizeof preedit, &resp))){
+		CT_EQ_STR(t, "abc", commit);
+		CT_EQ_STR(t, "xy", preedit);
+	}
+	close(fd[0]);
+	close(fd[1]);
+
+	if(socketpair(AF_UNIX, SOCK_STREAM, 0, fd) < 0){
+		CT_ERRORF(t, "socketpair failed");
+		return;
+	}
+	CT_EQ_INT(t, 0, ipcsend(fd[0], frame, n-1));
+	shutdown(fd[0], SHUT_WR);
+	CT_EQ_INT(t, -1, ipcreadresp(fd[1], 1, commit, sizeof commit,
+		preedit, sizeof preedit, &resp));
+	close(fd[0]);
+	close(fd[1]);
+}
+
+void
+ipc_broken_peer_send(struct ct *t)
+{
+	int fd[2];
+
+	if(socketpair(AF_UNIX, SOCK_STREAM, 0, fd) < 0){
+		CT_ERRORF(t, "socketpair failed");
+		return;
+	}
+	close(fd[1]);
+	CT_EQ_INT(t, -1, ipcsend(fd[0], "x", 1));
+	close(fd[0]);
+}
diff --git a/tests/test.h b/tests/test.h
index b360b82..0776244 100644
--- a/tests/test.h
+++ b/tests/test.h
@@ -65,5 +65,10 @@ void	dictionary_misses_clear_result(struct ct*);
 void	dictionary_emoji_identity(struct ct*);
 void	ipc_masks_modifiers(struct ct*);
 void	ipc_runtime_path(struct ct*);
+void	ipc_response_pack_boundaries(struct ct*);
+void	ipc_response_empty_and_preedit(struct ct*);
+void	ipc_response_max_and_drain(struct ct*);
+void	ipc_response_fragmented_and_truncated(struct ct*);
+void	ipc_broken_peer_send(struct ct*);
 
 #endif
diff --git a/tests/unit_test.c b/tests/unit_test.c
index ce28a33..815d5e1 100644
--- a/tests/unit_test.c
+++ b/tests/unit_test.c
@@ -114,6 +114,11 @@ static const struct ct_test tests[] = {
 	{ "dict/emoji-identity", dictionary_emoji_identity },
 	{ "ipc/masks-modifiers", ipc_masks_modifiers },
 	{ "ipc/runtime-path", ipc_runtime_path },
+	{ "ipc/response-pack-boundaries", ipc_response_pack_boundaries },
+	{ "ipc/response-empty-preedit", ipc_response_empty_and_preedit },
+	{ "ipc/response-max-drain", ipc_response_max_and_drain },
+	{ "ipc/response-fragmented-truncated", ipc_response_fragmented_and_truncated },
+	{ "ipc/broken-peer-send", ipc_broken_peer_send },
 };
 
 void