Discovery: Don't cache if TTL is zero.

Author: donquixote

src/Discovery/CollaboraDiscoveryFetcher.php

@@ -108,7 +108,13 @@ protected function getDiscoveryXml(): string {
     $discovery_url = $this->getDiscoveryUrl($config);
     $xml = $this->loadDiscoveryXml($discovery_url, $disable_checks);
 
+    /** @var non-negative-int $max_age */
     $max_age = $config->get('cool.discovery_cache_ttl') ?? 3600;
+    if ($max_age === 0) {
+      // The discovery cache is disabled.
+      return $xml;
+    }
+
     $expire = $max_age + $this->time->getRequestTime();
 
     $this->cache->set(

tests/src/Kernel/DiscoveryFetcherTest.php

@@ -188,9 +188,6 @@ public function testGetDiscoveryIsCached(): void {
     $fetcher->getDiscovery();
     $this->assertCount(5, $this->httpClientGetCalls);
     $fetcher->getDiscovery();
-    $this->assertCount(5, $this->httpClientGetCalls);
-    $this->mockRequestTime = $this->mockRequestTime->add(new \DateInterval('PT1S'));
-    $fetcher->getDiscovery();
     $this->assertCount(6, $this->httpClientGetCalls);
   }