diff --git a/Formula/postgresql@9.4.rb b/Formula/postgresql@9.4.rb
index f8c2170b30e66..ce5ff54d3ca80 100644
--- a/Formula/postgresql@9.4.rb
+++ b/Formula/postgresql@9.4.rb
@@ -65,10 +65,12 @@ def install
   end
 
   def post_install
-    return if ENV["CI"]
-
     (var/"log").mkpath
     postgresql_datadir.mkpath
+
+    # Don't initialize database, it clashes when testing other PostgreSQL versions.
+    return if ENV["HOMEBREW_GITHUB_ACTIONS"]
+
     system "#{bin}/initdb", postgresql_datadir unless pg_version_exists?
   end
 
@@ -131,8 +133,4 @@ def plist
       </plist>
     EOS
   end
-
-  test do
-    system "#{bin}/initdb", testpath/"test" unless ENV["CI"]
-  end
 end