diff --git a/unit/test-caif.c b/unit/test-caif.c
index 51e29bc6..2c63d4c0 100644
--- a/unit/test-caif.c
+++ b/unit/test-caif.c
@@ -124,7 +124,7 @@ static void test_connect(gboolean use_socket)
 
 	g_io_channel_unref(io);
 
-	if (!chat) {
+	if (chat == NULL) {
 		g_printerr("Chat creation failed\n");
 		return;
 	}
diff --git a/unit/test-mux.c b/unit/test-mux.c
index e80b47cf..d0e2d320 100644
--- a/unit/test-mux.c
+++ b/unit/test-mux.c
@@ -201,7 +201,7 @@ static void test_mux(void)
 
 	g_io_channel_unref(io);
 
-	if (!chat) {
+	if (chat == NULL) {
 		g_printerr("Chat creation failed\n");
 		return;
 	}
diff --git a/unit/test-simutil.c b/unit/test-simutil.c
index 7aa09b4b..155cddd6 100644
--- a/unit/test-simutil.c
+++ b/unit/test-simutil.c
@@ -372,7 +372,7 @@ static void test_eons()
 	sim_eons_optimize(eons_info);
 
 	op_info = sim_eons_lookup(eons_info, "246", "82");
-	g_assert(!op_info);
+	g_assert(op_info == NULL);
 	op_info = sim_eons_lookup(eons_info, "246", "81");
 	g_assert(op_info);
 
@@ -391,7 +391,7 @@ static void test_ef_db()
 	g_assert(info);
 
 	info = sim_ef_db_lookup(0x6FB1);
-	g_assert(!info);
+	g_assert(info == NULL);
 
 	info = sim_ef_db_lookup(0x2F05);
 	g_assert(info);