diff --git a/.travis.yml b/.travis.yml
index 5ebb129..88a3fe7 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -22,7 +22,7 @@ addons:
             - lcov
 
 before_install:
-    - sudo pip3 install --system meson
+    - sudo pip3 install --system 'meson==0.54.3'
 
 before_script:
     - meson -Db_coverage=true build
diff --git a/meson.build b/meson.build
index 56370d7..110a9f6 100644
--- a/meson.build
+++ b/meson.build
@@ -92,10 +92,10 @@ gmock_main_dep = dependency('gmock_main', version: '>=1.10.0', fallback: ['gtest
 
 openssl = find_program('openssl')
 test_server_certs = custom_target('test_server_certs',
-	output: ['server-key.pem', 'server-cert.pem'],
+	output: 'server-key.pem',
 	command: [openssl, 'req', '-x509', '-newkey', 'rsa:4096', '-keyout', 'server-key.pem', '-out', 'server-cert.pem', '-days', '365', '-nodes', '-batch', '-subj', '/CN=localhost'])
 test_client_certs = custom_target('test_client_certs',
-	output: ['client-key.pem', 'client-cert.pem'],
+	output: 'client-key.pem',
 	command: [openssl, 'req', '-x509', '-newkey', 'rsa:4096', '-keyout', 'client-key.pem', '-out', 'client-cert.pem', '-days', '365', '-nodes', '-batch', '-subj', '/CN=localhost'])
 
 test_certs_dep = declare_dependency(