diff --git a/test/src/sml_boolean_test.c b/test/src/sml_boolean_test.c
index 0df2013..b2f016e 100644
--- a/test/src/sml_boolean_test.c
+++ b/test/src/sml_boolean_test.c
@@ -24,13 +24,6 @@ TEST_GROUP(sml_boolean);
 
 sml_buffer *buf;
 
-void sml_boolean_test_expected_buf(char *hex, int len) {
-	unsigned char expected_buf[len];
-	hex2binary(hex, expected_buf);
-	TEST_ASSERT_EQUAL_MEMORY(expected_buf, buf->buffer, len);
-	TEST_ASSERT_EQUAL(len, buf->cursor);
-}
-
 TEST_SETUP(sml_boolean) {
 	buf = sml_buffer_init(512);
 }
@@ -68,12 +61,12 @@ TEST(sml_boolean, parse_optional) {
 TEST(sml_boolean, write) {
 	sml_boolean *b = sml_boolean_init(SML_BOOLEAN_TRUE);
 	sml_boolean_write(b, buf);
-	sml_boolean_test_expected_buf("42FF", 2);
+	expected_buf(buf, "42FF", 2);
 }
 
 TEST(sml_boolean, write_optional) {
 	sml_boolean_write(0, buf);
-	sml_boolean_test_expected_buf("01", 1);
+	expected_buf(buf, "01", 1);
 }
 
 
diff --git a/test/src/sml_number_test.c b/test/src/sml_number_test.c
index 7dcdf6a..5349bef 100644
--- a/test/src/sml_number_test.c
+++ b/test/src/sml_number_test.c
@@ -25,13 +25,6 @@ TEST_GROUP(sml_number);
 
 sml_buffer *buf;
 
-void sml_number_test_expected_buf(char *hex, int len) {
-	unsigned char expected_buf[len];
-	hex2binary(hex, expected_buf);
-	TEST_ASSERT_EQUAL_MEMORY(expected_buf, buf->buffer, len);
-	TEST_ASSERT_EQUAL(len, buf->cursor);
-}
-
 TEST_SETUP(sml_number) {
 	buf = sml_buffer_init(512);
 }
@@ -129,18 +122,18 @@ TEST(sml_number, parse_int64_fewer_bytes) {
 TEST(sml_number, write_unsigned8) {
 	u8 *n = sml_u8_init(1);
 	sml_u8_write(n, buf);
-	sml_number_test_expected_buf("6201", 2);
+	expected_buf(buf, "6201", 2);
 }
 
 TEST(sml_number, write_integer32) {
 	i32 *n = sml_i32_init(-5000);
 	sml_i32_write(n, buf);
-	sml_number_test_expected_buf("55FFFFEC78", 5);
+	expected_buf(buf, "55FFFFEC78", 5);
 }
 
 TEST(sml_number, write_integer8_optional) {
 	sml_i8_write(0, buf);
-	sml_number_test_expected_buf("01", 1);
+	expected_buf(buf, "01", 1);
 }
 
 TEST_GROUP_RUNNER(sml_number) {
diff --git a/test/src/sml_octet_string_test.c b/test/src/sml_octet_string_test.c
index db85441..97b68f7 100644
--- a/test/src/sml_octet_string_test.c
+++ b/test/src/sml_octet_string_test.c
@@ -24,19 +24,6 @@ TEST_GROUP(sml_octet_string);
 
 sml_buffer *buf;
 
-void expected_octet_string(octet_string *str, char *content, int len) {
-	TEST_ASSERT_NOT_NULL(str);
-	TEST_ASSERT_EQUAL(len, str->len);
-	TEST_ASSERT_EQUAL_MEMORY(content, str->str, len);
-}
-
-void sml_octet_string_expected_buf(char *hex, int len) {
-	unsigned char expected_buf[len];
-	hex2binary(hex, expected_buf);
-	TEST_ASSERT_EQUAL_MEMORY(expected_buf, buf->buffer, len);
-	TEST_ASSERT_EQUAL(len, buf->cursor);
-}
-
 TEST_SETUP(sml_octet_string) {
 	buf = sml_buffer_init(512);
 }
@@ -75,12 +62,12 @@ TEST(sml_octet_string, parse_optional) {
 TEST(sml_octet_string, write) {
 	octet_string *str = sml_octet_string_init((unsigned char *)"Hallo", 5);
 	sml_octet_string_write(str, buf);
-	sml_octet_string_expected_buf("0648616C6C6F", 6);
+	expected_buf(buf, "0648616C6C6F", 6);
 }
 
 TEST(sml_octet_string, write_optional) {
 	sml_octet_string_write(0, buf);
-	sml_octet_string_expected_buf("01", 1);
+	expected_buf(buf, "01", 1);
 }
 
 TEST(sml_octet_string, cmp) {
diff --git a/test/src/test_helper.c b/test/src/test_helper.c
index f5f9671..f7125d6 100644
--- a/test/src/test_helper.c
+++ b/test/src/test_helper.c
@@ -17,6 +17,7 @@
 // along with libSML.  If not, see <http://www.gnu.org/licenses/>.
 
 #include "test_helper.h"
+#include "../unity/unity_fixture.h"
 #include <stdint.h>
 #include <string.h>
 
@@ -51,3 +52,16 @@ int hex2binary(char *hex, unsigned char *buf) {
 	return i;
 }
 
+void expected_buf(sml_buffer *buf, char *hex, int len) {
+	unsigned char expected_buf[len];
+	hex2binary(hex, expected_buf);
+	TEST_ASSERT_EQUAL_MEMORY(expected_buf, buf->buffer, len);
+	TEST_ASSERT_EQUAL(len, buf->cursor);
+}
+
+void expected_octet_string(octet_string *str, char *content, int len) {
+	TEST_ASSERT_NOT_NULL(str);
+	TEST_ASSERT_EQUAL(len, str->len);
+	TEST_ASSERT_EQUAL_MEMORY(content, str->str, len);
+}
+
diff --git a/test/src/test_helper.h b/test/src/test_helper.h
index 4685ae6..64ad072 100644
--- a/test/src/test_helper.h
+++ b/test/src/test_helper.h
@@ -19,6 +19,11 @@
 #ifndef TEST_HELPER_H_
 #define TEST_HELPER_H_
 
+#include <sml/sml_shared.h>
+#include <sml/sml_octet_string.h>
+
 int hex2binary(char *hex, unsigned char *buf);
+void expected_buf(sml_buffer *buf, char *hex, int len);
+void expected_octet_string(octet_string *str, char *content, int len);
 
 #endif