diff --git a/tests/data_files/Makefile b/tests/data_files/Makefile
index 4222fb862..f01806329 100644
--- a/tests/data_files/Makefile
+++ b/tests/data_files/Makefile
@@ -931,9 +931,9 @@ server1.crt: server1.key server1.req.sha256 $(test_ca_crt) $(test_ca_key_file_rs
 	$(MBEDTLS_CERT_WRITE) request_file=server1.req.sha256 issuer_crt=$(test_ca_crt) issuer_key=$(test_ca_key_file_rsa) issuer_pwd=$(test_ca_pwd_rsa) version=1 not_before=20110212144406 not_after=20210212144406 md=SHA1 version=3 output_file=$@
 server1.noauthid.crt: server1.key server1.req.sha256 $(test_ca_crt) $(test_ca_key_file_rsa)
 	$(MBEDTLS_CERT_WRITE) request_file=server1.req.sha256 issuer_crt=$(test_ca_crt) issuer_key=$(test_ca_key_file_rsa) issuer_pwd=$(test_ca_pwd_rsa) not_before=20110212144406 not_after=20210212144406 md=SHA1 authority_identifier=0 version=3 output_file=$@
-server1.der: server1.crt
+server1.crt.der: server1.crt
 	$(OPENSSL) x509 -inform PEM -in $< -outform DER -out $@
-all_final += server1.crt server1.noauthid.crt server1.der
+all_final += server1.crt server1.noauthid.crt server1.crt.der
 
 server1.key_usage.crt: server1.key server1.req.sha256 $(test_ca_crt) $(test_ca_key_file_rsa)
 	$(MBEDTLS_CERT_WRITE) request_file=server1.req.sha256 issuer_crt=$(test_ca_crt) issuer_key=$(test_ca_key_file_rsa) issuer_pwd=$(test_ca_pwd_rsa) version=1 not_before=20110212144406 not_after=20210212144406 md=SHA1 key_usage=digital_signature,non_repudiation,key_encipherment version=3 output_file=$@
diff --git a/tests/data_files/server1.der b/tests/data_files/server1.crt.der
similarity index 100%
rename from tests/data_files/server1.der
rename to tests/data_files/server1.crt.der
diff --git a/tests/suites/test_suite_x509parse.data b/tests/suites/test_suite_x509parse.data
index 90e2da1e5..04dc81326 100644
--- a/tests/suites/test_suite_x509parse.data
+++ b/tests/suites/test_suite_x509parse.data
@@ -4,7 +4,7 @@ x509_cert_info:"data_files/server1.crt":"cert. version     \: 3\nserial number
 
 X509 Certificate information #1 (DER)
 depends_on:MBEDTLS_RSA_C:MBEDTLS_SHA1_C
-x509_cert_info:"data_files/server1.der":"cert. version     \: 3\nserial number     \: 01\nissuer name       \: C=NL, O=PolarSSL, CN=PolarSSL Test CA\nsubject name      \: C=NL, O=PolarSSL, CN=PolarSSL Server 1\nissued  on        \: 2011-02-12 14\:44\:06\nexpires on        \: 2021-02-12 14\:44\:06\nsigned using      \: RSA with SHA1\nRSA key size      \: 2048 bits\nbasic constraints \: CA=false\n"
+x509_cert_info:"data_files/server1.crt.der":"cert. version     \: 3\nserial number     \: 01\nissuer name       \: C=NL, O=PolarSSL, CN=PolarSSL Test CA\nsubject name      \: C=NL, O=PolarSSL, CN=PolarSSL Server 1\nissued  on        \: 2011-02-12 14\:44\:06\nexpires on        \: 2021-02-12 14\:44\:06\nsigned using      \: RSA with SHA1\nRSA key size      \: 2048 bits\nbasic constraints \: CA=false\n"
 
 X509 Certificate information #2
 depends_on:MBEDTLS_PEM_PARSE_C:MBEDTLS_RSA_C:MBEDTLS_SHA1_C