diff --git a/tests/data_files/Makefile b/tests/data_files/Makefile
index ce4a25794..27f2afa91 100644
--- a/tests/data_files/Makefile
+++ b/tests/data_files/Makefile
@@ -341,6 +341,9 @@ server5-tricky-ip-san.crt: server5.key
 server5-directoryname.crt: server5.key
 	$(OPENSSL) req -x509 -new -subj "/C=UK/O=Mbed TLS/CN=Mbed TLS directoryName SAN" -set_serial 77 -config $(test_ca_config_file) -extensions directory_name_san -days 3650 -sha256 -key server5.key -out $@
 
+server5-two-directorynames.crt: server5.key
+	$(OPENSSL) req -x509 -new -subj "/C=UK/O=Mbed TLS/CN=Mbed TLS directoryName SAN" -set_serial 77 -config $(test_ca_config_file) -extensions two_directorynames -days 3650 -sha256 -key server5.key -out $@
+
 all_final += server5-tricky-ip-san.crt
 
 rsa_single_san_uri.crt.der: rsa_single_san_uri.key
diff --git a/tests/data_files/server5-two-directorynames.crt b/tests/data_files/server5-two-directorynames.crt
new file mode 100644
index 000000000..aa76c16fc
--- /dev/null
+++ b/tests/data_files/server5-two-directorynames.crt
@@ -0,0 +1,13 @@
+-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----
diff --git a/tests/data_files/test-ca.opensslconf b/tests/data_files/test-ca.opensslconf
index 16afebf77..a642b7379 100644
--- a/tests/data_files/test-ca.opensslconf
+++ b/tests/data_files/test-ca.opensslconf
@@ -103,7 +103,13 @@ nsCertType=client
 [directory_name_san]
 subjectAltName=dirName:dirname_sect
 
+[bad_second_directory_name_san]
+subjectAltName=dirName:dirname_sect, dirName:dirname_sect_bad
+
 [dirname_sect]
 C=UK
 O=Mbed TLS
 CN=Mbed TLS directoryName SAN
+
+[two_directorynames]
+O=MALFORM_ME