Test MySQLi connection via TLS on Travis

.travis.yml

@@ -185,6 +185,9 @@ jobs:
     - stage: Test
       php: 7.4
       env: DB=mysqli.docker IMAGE=mysql:8.0
+    - stage: Test
+      php: 7.4
+      env: DB=mysqli-tls.docker IMAGE=mysql:8.0 TLS=yes
     - stage: Test
       php: 7.4
       env: DB=mariadb.docker IMAGE=mariadb:10.3

tests/travis/docker-run-mysql-or-mariadb.sh

@@ -40,3 +40,11 @@ while true; do
       ;;
   esac
 done
+
+if [[ "$TLS" == "yes" ]]
+then
+  for file in "ca.pem" "client-cert.pem" "client-key.pem"
+  do
+    docker cp "rdbms:/var/lib/mysql/$file" .
+  done
+fi

tests/travis/mysqli-tls.docker.travis.xml

+<?xml version="1.0" encoding="utf-8"?>
+<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:noNamespaceSchemaLocation="../../vendor/phpunit/phpunit/phpunit.xsd"
+         colors="true"
+         beStrictAboutOutputDuringTests="true"
+         beStrictAboutTodoAnnotatedTests="true"
+         failOnRisky="true"
+         failOnWarning="true"
+>
+    <php>
+        <var name="db_driver" value="mysqli"/>
+        <var name="db_host" value="127.0.0.1"/>
+        <var name="db_port" value="33306"/>
+        <var name="db_ssl_ca" value="ca.pem"/>
+        <var name="db_ssl_cert" value="client-cert.pem"/>
+        <var name="db_ssl_key" value="client-key.pem"/>
+
+        <!-- Use MYSQLI_CLIENT_SSL_DONT_VERIFY_SERVER_CERT since there's no way to generate a certificate
+        with a proper common name (CN) on Travis. This flag must be not used in production settings. -->
+        <var name="db_driver_option_flags" value="64"/>
+
+        <var name="db_user" value="root"/>
+        <var name="db_dbname" value="doctrine_tests"/>
+    </php>
+
+    <testsuites>
+        <testsuite name="Doctrine DBAL Test Suite">
+            <directory>../Doctrine/Tests/DBAL</directory>
+        </testsuite>
+    </testsuites>
+
+    <filter>
+        <whitelist>
+            <directory suffix=".php">../../lib/Doctrine</directory>
+        </whitelist>
+    </filter>
+
+    <groups>
+        <exclude>
+            <group>performance</group>
+            <group>locking_functional</group>
+        </exclude>
+    </groups>
+</phpunit>