diff --git a/library/common.h b/library/common.h
index eb159a7..68af840 100644
--- a/library/common.h
+++ b/library/common.h
@@ -65,6 +65,44 @@
 #define MBEDTLS_TEST_HOOK_TEST_ASSERT(TEST)
 #endif /* defined(MBEDTLS_TEST_HOOKS) */
 
+/** \def ARRAY_LENGTH
+ * Return the number of elements of a static or stack array.
+ *
+ * \param array         A value of array (not pointer) type.
+ *
+ * \return The number of elements of the array.
+ */
+/* A correct implementation of ARRAY_LENGTH, but which silently gives
+ * a nonsensical result if called with a pointer rather than an array. */
+#define ARRAY_LENGTH_UNSAFE(array)            \
+    (sizeof(array) / sizeof(*(array)))
+
+#if defined(__GNUC__)
+/* Test if arg and &(arg)[0] have the same type. This is true if arg is
+ * an array but not if it's a pointer. */
+#define IS_ARRAY_NOT_POINTER(arg)                                     \
+    (!__builtin_types_compatible_p(__typeof__(arg),                \
+                                   __typeof__(&(arg)[0])))
+/* A compile-time constant with the value 0. If `const_expr` is not a
+ * compile-time constant with a nonzero value, cause a compile-time error. */
+#define STATIC_ASSERT_EXPR(const_expr)                                \
+    (0 && sizeof(struct { unsigned int STATIC_ASSERT : 1 - 2 * !(const_expr); }))
+
+/* Return the scalar value `value` (possibly promoted). This is a compile-time
+ * constant if `value` is. `condition` must be a compile-time constant.
+ * If `condition` is false, arrange to cause a compile-time error. */
+#define STATIC_ASSERT_THEN_RETURN(condition, value)   \
+    (STATIC_ASSERT_EXPR(condition) ? 0 : (value))
+
+#define ARRAY_LENGTH(array)                                           \
+    (STATIC_ASSERT_THEN_RETURN(IS_ARRAY_NOT_POINTER(array),         \
+                               ARRAY_LENGTH_UNSAFE(array)))
+
+#else
+/* If we aren't sure the compiler supports our non-standard tricks,
+ * fall back to the unsafe implementation. */
+#define ARRAY_LENGTH(array) ARRAY_LENGTH_UNSAFE(array)
+#endif
 /** Allow library to access its structs' private members.
  *
  * Although structs defined in header files are publicly available,
diff --git a/library/psa_crypto.c b/library/psa_crypto.c
index 399e7f3..f735d88 100644
--- a/library/psa_crypto.c
+++ b/library/psa_crypto.c
@@ -84,8 +84,6 @@
 #include "mbedtls/sha512.h"
 #include "md_psa.h"
 
-#define ARRAY_LENGTH(array) (sizeof(array) / sizeof(*(array)))
-
 #if defined(MBEDTLS_PSA_BUILTIN_ALG_HKDF) ||          \
     defined(MBEDTLS_PSA_BUILTIN_ALG_HKDF_EXTRACT) ||  \
     defined(MBEDTLS_PSA_BUILTIN_ALG_HKDF_EXPAND)
diff --git a/library/psa_crypto_slot_management.c b/library/psa_crypto_slot_management.c
index a7cb9b5..a10cb2b 100644
--- a/library/psa_crypto_slot_management.c
+++ b/library/psa_crypto_slot_management.c
@@ -36,8 +36,6 @@
 #include <string.h>
 #include "mbedtls/platform.h"
 
-#define ARRAY_LENGTH(array) (sizeof(array) / sizeof(*(array)))
-
 typedef struct {
     psa_key_slot_t key_slots[MBEDTLS_PSA_KEY_SLOT_COUNT];
     unsigned key_slots_initialized : 1;
diff --git a/library/sha512.c b/library/sha512.c
index b8b2485..ff92a1b 100644
--- a/library/sha512.c
+++ b/library/sha512.c
@@ -1001,8 +1001,6 @@
 };
 #endif /* MBEDTLS_SHA512_C */
 
-#define ARRAY_LENGTH(a)   (sizeof(a) / sizeof((a)[0]))
-
 static int mbedtls_sha512_common_self_test(int verbose, int is384)
 {
     int i, buflen, ret = 0;
diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index 7601e5b..fc44dbe 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -759,8 +759,6 @@
 }
 
 #if defined(MBEDTLS_SSL_PROTO_TLS1_3) && defined(MBEDTLS_SSL_SESSION_TICKETS)
-#define ARRAY_LENGTH(a) (sizeof(a) / sizeof(*(a)))
-
 static const char *ticket_flag_name_table[] =
 {
     [0] = "ALLOW_PSK_RESUMPTION",
diff --git a/tests/include/test/macros.h b/tests/include/test/macros.h
index ab8260b..01eaff5 100644
--- a/tests/include/test/macros.h
+++ b/tests/include/test/macros.h
@@ -196,45 +196,6 @@
         mbedtls_exit(1);                                              \
     }
 
-/** \def ARRAY_LENGTH
- * Return the number of elements of a static or stack array.
- *
- * \param array         A value of array (not pointer) type.
- *
- * \return The number of elements of the array.
- */
-/* A correct implementation of ARRAY_LENGTH, but which silently gives
- * a nonsensical result if called with a pointer rather than an array. */
-#define ARRAY_LENGTH_UNSAFE(array)            \
-    (sizeof(array) / sizeof(*(array)))
-
-#if defined(__GNUC__)
-/* Test if arg and &(arg)[0] have the same type. This is true if arg is
- * an array but not if it's a pointer. */
-#define IS_ARRAY_NOT_POINTER(arg)                                     \
-    (!__builtin_types_compatible_p(__typeof__(arg),                \
-                                   __typeof__(&(arg)[0])))
-/* A compile-time constant with the value 0. If `const_expr` is not a
- * compile-time constant with a nonzero value, cause a compile-time error. */
-#define STATIC_ASSERT_EXPR(const_expr)                                \
-    (0 && sizeof(struct { unsigned int STATIC_ASSERT : 1 - 2 * !(const_expr); }))
-
-/* Return the scalar value `value` (possibly promoted). This is a compile-time
- * constant if `value` is. `condition` must be a compile-time constant.
- * If `condition` is false, arrange to cause a compile-time error. */
-#define STATIC_ASSERT_THEN_RETURN(condition, value)   \
-    (STATIC_ASSERT_EXPR(condition) ? 0 : (value))
-
-#define ARRAY_LENGTH(array)                                           \
-    (STATIC_ASSERT_THEN_RETURN(IS_ARRAY_NOT_POINTER(array),         \
-                               ARRAY_LENGTH_UNSAFE(array)))
-
-#else
-/* If we aren't sure the compiler supports our non-standard tricks,
- * fall back to the unsafe implementation. */
-#define ARRAY_LENGTH(array) ARRAY_LENGTH_UNSAFE(array)
-#endif
-
 /** Return the smaller of two values.
  *
  * \param x         An integer-valued expression without side effects.
diff --git a/tests/src/psa_crypto_helpers.c b/tests/src/psa_crypto_helpers.c
index 77c2f89..8f58d4d 100644
--- a/tests/src/psa_crypto_helpers.c
+++ b/tests/src/psa_crypto_helpers.c
@@ -24,6 +24,7 @@
 #include <test/macros.h>
 #include <psa_crypto_slot_management.h>
 #include <test/psa_crypto_helpers.h>
+#include "common.h"
 
 #if defined(MBEDTLS_PSA_CRYPTO_C)