Copy files before starting container

Move the copy-to-container step before containerStart() so files configured with
withCopyFilesToContainer(), withCopyDirectoriesToContainer(), or
withCopyContentToContainer() are available when the container entrypoint starts.

This avoids races for images that read configuration immediately on startup, such
as Caddy loading /etc/caddy/Caddyfile before the test-provided file has been
copied into the container.

Author: nightio

src/Container/GenericContainer.php

@@ -338,12 +338,12 @@ public function start(): StartedGenericContainer
             return $this->start();
         }
 
-        $this->dockerClient->containerStart($this->id);
-
         if ($this->filesToCopy !== [] || $this->directoriesToCopy !== [] || $this->contentsToCopy !== []) {
             $this->copyToContainer();
         }
 
+        $this->dockerClient->containerStart($this->id);
+
         $startedContainer = new StartedGenericContainer($this->id);
         $this->waitStrategy->wait($startedContainer);