Added test to ensure CacheItemPool is not cloned in CachingConnector.

Removed note in Readme about caching not being supported.

README.md

@@ -290,8 +290,6 @@ Any connector can be wrapped in a `CachingConnector` to provide [PSR-6][] cachin
 
 Remember that whilst using a `CachingConnector` enables caching, caching must also be enabled on a per-import basis by calling `Import::enableCache()`.
 
-Note that Caching is not yet supported for asynchronous imports.
-
 ### Example
 
 The follow example enables connector caching.

src/Provider/Provider.php

@@ -12,6 +12,8 @@ interface Provider
 {
     /**
      * Gets a connector compatible with this provider's resources.
+     *
+     * NB: this should not be a factory method as it will break things like caching.
      */
     public function getConnector(): Connector;
 }

test/Integration/Connector/CachingConnectorTest.php

@@ -65,7 +65,7 @@ public function testCacheBypassedForDifferentOptions(): void
     }
 
     /**
-     * That that when the generated cache key contains non-compliant PSR-6 characters,
+     * Tests that when the generated cache key contains non-compliant PSR-6 characters,
      * InvalidCacheKeyException is thrown.
      */
     public function testValidateCacheKey(): void
@@ -88,10 +88,26 @@ public function testGetWrappedConnector(): void
     /**
      * Tests that cloning the caching connector also clones the wrapped connector.
      */
-    public function testClone(): void
+    public function testCloneConnector(): void
     {
         $clone = clone $this->connector;
 
         self::assertNotSame($this->wrappedConnector, $clone->getWrappedConnector());
     }
+
+    /**
+     * Tests that cloning the caching connector does not clone the cache item pool (both instances point to the same
+     * pool).
+     */
+    public function testCloneCacheItemPool(): void
+    {
+        $clone = clone $this->connector;
+
+        $cacheA = \Closure::bind(fn () => $this->cache, $this->connector, $this->connector)();
+        $cacheB = \Closure::bind(fn () => $this->cache, $clone, $clone)();
+        self::assertSame($cacheA, $cacheB);
+
+        $clone->fetch($this->source);
+        self::assertSame(1, $cacheA->count(), 'Fetch on clone updates original cache item pool.');
+    }
 }