diff --git a/Formula/mysql@5.6.rb b/Formula/mysql@5.6.rb
index 7350a70ca129a..4e8010ae21d3e 100644
--- a/Formula/mysql@5.6.rb
+++ b/Formula/mysql@5.6.rb
@@ -93,10 +93,12 @@ def install
   end
 
   def post_install
-    return if ENV["CI"]
+    # Make sure the var/mysql directory exists
+    (var/"mysql").mkpath
+
+    # Don't initialize database, it clashes when testing other MySQL-like implementations.
+    return if ENV["HOMEBREW_GITHUB_ACTIONS"]
 
-    # Make sure the datadir exists
-    datadir.mkpath
     unless (datadir/"mysql/general_log.CSM").exist?
       ENV["TMPDIR"] = nil
       system bin/"mysql_install_db", "--verbose", "--user=#{ENV["USER"]}",