make PHP testsuite work with PHPUnit6

test/php/phpunit.xml

@@ -0,0 +1,27 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<phpunit backupGlobals="false"
+    backupStaticAttributes="false"
+    colors="true"
+    convertErrorsToExceptions="true"
+    convertNoticesToExceptions="true"
+    convertWarningsToExceptions="true"
+    processIsolation="false"
+    stopOnFailure="false"
+    syntaxCheck="true"
+    bootstrap="./bootstrap.php"
+    beStrictAboutTestsThatDoNotTestAnything="true"
+    >
+    <php>
+    </php>
+    <testsuites>
+        <testsuite name="Nominatim PHP Test Suite">
+            <directory>./Nominatim</directory>
+        </testsuite>
+    </testsuites>
+    <filter>
+        <whitelist>
+            <directory>./lib/</directory>
+        </whitelist>
+    </filter>
+
+</phpunit>