diff --git a/tests/suites/test_suite_pk.data b/tests/suites/test_suite_pk.data
index 0da3241..e41dfa7 100644
--- a/tests/suites/test_suite_pk.data
+++ b/tests/suites/test_suite_pk.data
@@ -4,6 +4,10 @@
 PK valid parameters
 valid_parameters:
 
+PK write valid parameters
+depends_on:MBEDTLS_RSA_C
+valid_parameters_pkwrite:"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"
+
 PK utils: RSA
 depends_on:MBEDTLS_RSA_C:MBEDTLS_GENPRIME
 pk_utils:MBEDTLS_PK_RSA:512:64:"RSA"
diff --git a/tests/suites/test_suite_pk.function b/tests/suites/test_suite_pk.function
index b8069b5..20b5457 100644
--- a/tests/suites/test_suite_pk.function
+++ b/tests/suites/test_suite_pk.function
@@ -2,6 +2,8 @@
 #include "mbedtls/pk.h"
 
 /* For error codes */
+#include "mbedtls/asn1.h"
+#include "mbedtls/base64.h"
 #include "mbedtls/ecp.h"
 #include "mbedtls/rsa.h"
 
@@ -111,14 +113,36 @@
     TEST_ASSERT( mbedtls_pk_parse_public_key( &pk, NULL, 0 ) ==
                  MBEDTLS_ERR_PK_KEY_INVALID_FORMAT );
 #endif /* MBEDTLS_PK_PARSE_C */
+}
+/* END_CASE */
 
-#if defined(MBEDTLS_PK_WRITE_C)
+/* BEGIN_CASE depends_on:MBEDTLS_PK_WRITE_C */
+void valid_parameters_pkwrite( data_t *key_data )
+{
+    mbedtls_pk_context pk;
+
+    /* For the write tests to be effective, we need a valid key pair. */
+    mbedtls_pk_init( &pk );
+    TEST_ASSERT( mbedtls_pk_parse_key( &pk,
+                                       key_data->x, key_data->len,
+                                       NULL, 0 ) == 0 );
+
     TEST_ASSERT( mbedtls_pk_write_key_der( &pk, NULL, 0 ) ==
-                 MBEDTLS_ERR_PK_FEATURE_UNAVAILABLE );
+                 MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
 
     TEST_ASSERT( mbedtls_pk_write_pubkey_der( &pk, NULL, 0 ) ==
-                 MBEDTLS_ERR_PK_FEATURE_UNAVAILABLE );
-#endif /* MBEDTLS_PK_WRITE_C */
+                 MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
+
+#if defined(MBEDTLS_PEM_WRITE_C)
+    TEST_ASSERT( mbedtls_pk_write_key_pem( &pk, NULL, 0 ) ==
+                 MBEDTLS_ERR_BASE64_BUFFER_TOO_SMALL );
+
+    TEST_ASSERT( mbedtls_pk_write_pubkey_pem( &pk, NULL, 0 ) ==
+                 MBEDTLS_ERR_BASE64_BUFFER_TOO_SMALL );
+#endif /* MBEDTLS_PEM_WRITE_C */
+
+exit:
+    mbedtls_pk_free( &pk );
 }
 /* END_CASE */