diff --git a/tests/Makefile b/tests/Makefile
index ad7affb..7fb4f35 100644
--- a/tests/Makefile
+++ b/tests/Makefile
@@ -112,68 +112,9 @@
 
 mbedtls_test: $(MBEDTLS_TEST_OBJS)
 
-TEST_CERTS_H_INPUT_FILES=\
-					data_files/test-ca2.crt \
-					data_files/test-ca2.crt.der \
-					data_files/test-ca2.key.enc \
-					data_files/test-ca2.key.der \
-					data_files/test-ca-sha256.crt \
-					data_files/test-ca-sha256.crt.der \
-					data_files/test-ca-sha1.crt \
-					data_files/test-ca-sha1.crt.der \
-					data_files/test-ca.key \
-					data_files/test-ca.key.der \
-					data_files/server5.crt \
-					data_files/server5.crt.der \
-					data_files/server5.key \
-					data_files/server5.key.der \
-					data_files/server2-sha256.crt \
-					data_files/server2-sha256.crt.der \
-					data_files/server2.crt \
-					data_files/server2.crt.der \
-					data_files/server2.key \
-					data_files/server2.key.der \
-					data_files/cli2.crt \
-					data_files/cli2.crt.der \
-					data_files/cli2.key \
-					data_files/cli2.key.der \
-					data_files/cli-rsa-sha256.crt \
-					data_files/cli-rsa-sha256.crt.der \
-					data_files/cli-rsa.key \
-					data_files/cli-rsa.key.der
 src/test_certs.h: scripts/generate_test_cert_macros.py \
-					 $(TEST_CERTS_H_INPUT_FILES)
-	$(PYTHON) scripts/generate_test_cert_macros.py --output $@ \
-				--string TEST_CA_CRT_EC_PEM=data_files/test-ca2.crt \
-				--binary TEST_CA_CRT_EC_DER=data_files/test-ca2.crt.der \
-				--string TEST_CA_KEY_EC_PEM=data_files/test-ca2.key.enc \
-				--password TEST_CA_PWD_EC_PEM=PolarSSLTest \
-				--binary TEST_CA_KEY_EC_DER=data_files/test-ca2.key.der \
-				--string TEST_CA_CRT_RSA_SHA256_PEM=data_files/test-ca-sha256.crt \
-				--binary TEST_CA_CRT_RSA_SHA256_DER=data_files/test-ca-sha256.crt.der \
-				--string TEST_CA_CRT_RSA_SHA1_PEM=data_files/test-ca-sha1.crt \
-				--binary TEST_CA_CRT_RSA_SHA1_DER=data_files/test-ca-sha1.crt.der \
-				--string TEST_CA_KEY_RSA_PEM=data_files/test-ca.key \
-				--password TEST_CA_PWD_RSA_PEM=PolarSSLTest \
-				--binary TEST_CA_KEY_RSA_DER=data_files/test-ca.key.der \
-				--string TEST_SRV_CRT_EC_PEM=data_files/server5.crt \
-				--binary TEST_SRV_CRT_EC_DER=data_files/server5.crt.der \
-				--string TEST_SRV_KEY_EC_PEM=data_files/server5.key \
-				--binary TEST_SRV_KEY_EC_DER=data_files/server5.key.der \
-				--string TEST_SRV_CRT_RSA_SHA256_PEM=data_files/server2-sha256.crt \
-				--binary TEST_SRV_CRT_RSA_SHA256_DER=data_files/server2-sha256.crt.der \
-				--string TEST_SRV_CRT_RSA_SHA1_PEM=data_files/server2.crt \
-				--binary TEST_SRV_CRT_RSA_SHA1_DER=data_files/server2.crt.der \
-				--string TEST_SRV_KEY_RSA_PEM=data_files/server2.key \
-				--binary TEST_SRV_KEY_RSA_DER=data_files/server2.key.der \
-				--string TEST_CLI_CRT_EC_PEM=data_files/cli2.crt \
-				--binary TEST_CLI_CRT_EC_DER=data_files/cli2.crt.der \
-				--string TEST_CLI_KEY_EC_PEM=data_files/cli2.key \
-				--binary TEST_CLI_KEY_EC_DER=data_files/cli2.key.der \
-				--string TEST_CLI_CRT_RSA_PEM=data_files/cli-rsa-sha256.crt \
-				--binary TEST_CLI_CRT_RSA_DER=data_files/cli-rsa-sha256.crt.der \
-				--string TEST_CLI_KEY_RSA_PEM=data_files/cli-rsa.key \
-				--binary TEST_CLI_KEY_RSA_DER=data_files/cli-rsa.key.der
+				  $($(PYTHON) scripts/generate_test_cert_macros.py --list-dependencies)
+	$(PYTHON) scripts/generate_test_cert_macros.py --output $@
 
 src/test_keys.h: scripts/generate_test_keys.py
 	$(PYTHON) scripts/generate_test_keys.py --output $@
diff --git a/tests/scripts/generate_test_cert_macros.py b/tests/scripts/generate_test_cert_macros.py
index a3bca7e..e612f62 100755
--- a/tests/scripts/generate_test_cert_macros.py
+++ b/tests/scripts/generate_test_cert_macros.py
@@ -14,51 +14,61 @@
 import argparse
 import jinja2
 
-class MacroDefineAction(argparse.Action):
-    #pylint: disable=signature-differs, too-few-public-methods
-    def __call__(self, parser, namespace, values, option_string):
-        if not hasattr(namespace, 'values'):
-            setattr(namespace, 'values', [])
-        macro_name, filename = values
-        if self.dest in ('string', 'binary') and not os.path.exists(filename):
-            raise argparse.ArgumentError(
-                None, '`{}`: Input file does not exist.'.format(filename))
-        namespace.values.append((self.dest, macro_name, filename))
+this_dir = os.path.dirname(os.path.abspath(__file__))
+data_files_path = os.path.join(this_dir, '..', 'data_files')
 
-
-def macro_define_type(value):
-    ret = value.split('=', 1)
-    if len(ret) != 2:
-        raise argparse.ArgumentTypeError(
-            '`{}` is not MACRO=value format'.format(value))
-    return ret
-
-
-def build_argparser(parser):
-    parser.description = __doc__
-    parser.add_argument('--string', type=macro_define_type, action=MacroDefineAction,
-                        metavar='MACRO_NAME=path/to/file', help='PEM to C string. ')
-    parser.add_argument('--binary', type=macro_define_type, action=MacroDefineAction,
-                        metavar='MACRO_NAME=path/to/file',
-                        help='DER to C arrary.')
-    parser.add_argument('--password', type=macro_define_type, action=MacroDefineAction,
-                        metavar='MACRO_NAME=password', help='Password to C string.')
-    parser.add_argument('--output', type=str, required=True)
-
+INPUT_ARGS = [
+    ("string", "TEST_CA_CRT_EC_PEM", data_files_path + "/test-ca2.crt"),
+    ("binary", "TEST_CA_CRT_EC_DER", data_files_path + "/test-ca2.crt.der"),
+    ("string", "TEST_CA_KEY_EC_PEM", data_files_path + "/test-ca2.key.enc"),
+    ("password", "TEST_CA_PWD_EC_PEM", "PolarSSLTest"),
+    ("binary", "TEST_CA_KEY_EC_DER", data_files_path + "/test-ca2.key.der"),
+    ("string", "TEST_CA_CRT_RSA_SHA256_PEM", data_files_path + "/test-ca-sha256.crt"),
+    ("binary", "TEST_CA_CRT_RSA_SHA256_DER", data_files_path + "/test-ca-sha256.crt.der"),
+    ("string", "TEST_CA_CRT_RSA_SHA1_PEM", data_files_path + "/test-ca-sha1.crt"),
+    ("binary", "TEST_CA_CRT_RSA_SHA1_DER", data_files_path + "/test-ca-sha1.crt.der"),
+    ("string", "TEST_CA_KEY_RSA_PEM", data_files_path + "/test-ca.key"),
+    ("password", "TEST_CA_PWD_RSA_PEM", "PolarSSLTest"),
+    ("binary", "TEST_CA_KEY_RSA_DER", data_files_path + "/test-ca.key.der"),
+    ("string", "TEST_SRV_CRT_EC_PEM", data_files_path + "/server5.crt"),
+    ("binary", "TEST_SRV_CRT_EC_DER", data_files_path + "/server5.crt.der"),
+    ("string", "TEST_SRV_KEY_EC_PEM", data_files_path + "/server5.key"),
+    ("binary", "TEST_SRV_KEY_EC_DER", data_files_path + "/server5.key.der"),
+    ("string", "TEST_SRV_CRT_RSA_SHA256_PEM", data_files_path + "/server2-sha256.crt"),
+    ("binary", "TEST_SRV_CRT_RSA_SHA256_DER", data_files_path + "/server2-sha256.crt.der"),
+    ("string", "TEST_SRV_CRT_RSA_SHA1_PEM", data_files_path + "/server2.crt"),
+    ("binary", "TEST_SRV_CRT_RSA_SHA1_DER", data_files_path + "/server2.crt.der"),
+    ("string", "TEST_SRV_KEY_RSA_PEM", data_files_path + "/server2.key"),
+    ("binary", "TEST_SRV_KEY_RSA_DER", data_files_path + "/server2.key.der"),
+    ("string", "TEST_CLI_CRT_EC_PEM", data_files_path + "/cli2.crt"),
+    ("binary", "TEST_CLI_CRT_EC_DER", data_files_path + "/cli2.crt.der"),
+    ("string", "TEST_CLI_KEY_EC_PEM", data_files_path + "/cli2.key"),
+    ("binary", "TEST_CLI_KEY_EC_DER", data_files_path + "/cli2.key.der"),
+    ("string", "TEST_CLI_CRT_RSA_PEM", data_files_path + "/cli-rsa-sha256.crt"),
+    ("binary", "TEST_CLI_CRT_RSA_DER", data_files_path + "/cli-rsa-sha256.crt.der"),
+    ("string", "TEST_CLI_KEY_RSA_PEM", data_files_path + "/cli-rsa.key"),
+    ("binary", "TEST_CLI_KEY_RSA_DER", data_files_path + "/cli-rsa.key.der"),
+]
 
 def main():
     parser = argparse.ArgumentParser()
-    build_argparser(parser)
+    default_output_path = os.path.join(this_dir, '..', 'test_certs.h')
+    parser.add_argument('--output', type=str, default=default_output_path)
+    parser.add_argument('--list-dependencies', action='store_true')
     args = parser.parse_args()
-    return generate(**vars(args))
+
+    if (args.list_dependencies is True):
+        files_list = [arg[2] for arg in INPUT_ARGS]
+        print(" ".join(files_list))
+        return
+
+    return generate(INPUT_ARGS, output=args.output)
 
 #pylint: disable=dangerous-default-value, unused-argument
-def generate(values=[], output=None, **kwargs):
+def generate(values=[], output=None):
     """Generate C header file.
     """
-    this_dir = os.path.dirname(os.path.abspath(__file__))
-    template_loader = jinja2.FileSystemLoader(
-        searchpath=os.path.join(this_dir, '..', 'data_files'))
+    template_loader = jinja2.FileSystemLoader(data_files_path)
     template_env = jinja2.Environment(
         loader=template_loader, lstrip_blocks=True, trim_blocks=True)