improve exeption message (#2041)

* improve exeption message

* add test

Author: ronfroy

src/Bridge/Symfony/Routing/IriConverter.php

@@ -115,7 +115,7 @@ public function getIriFromItem($item, int $referenceType = UrlGeneratorInterface
         $routeName = $this->routeNameResolver->getRouteName($resourceClass, OperationType::ITEM);
 
         try {
-            $identifiers = $this->generateIdentifiersUrl($this->identifiersExtractor->getIdentifiersFromItem($item));
+            $identifiers = $this->generateIdentifiersUrl($this->identifiersExtractor->getIdentifiersFromItem($item), $resourceClass);
 
             return $this->router->generate($routeName, ['id' => implode(';', $identifiers)], $referenceType);
         } catch (RuntimeException $e) {
@@ -170,12 +170,22 @@ public function getSubresourceIriFromResourceClass(string $resourceClass, array
     /**
      * Generate the identifier url.
      *
-     * @param array $identifiers
+     * @param array  $identifiers
+     * @param string $resourceClass
+     *
+     * @throws InvalidArgumentException
      *
      * @return string[]
      */
-    private function generateIdentifiersUrl(array $identifiers): array
+    private function generateIdentifiersUrl(array $identifiers, string $resourceClass): array
     {
+        if (0 === \count($identifiers)) {
+            throw new InvalidArgumentException(sprintf(
+                'No identifiers defined for resource of type "%s"',
+                $resourceClass
+            ));
+        }
+
         if (1 === \count($identifiers)) {
             return [rawurlencode((string) array_values($identifiers)[0])];
         }

tests/Bridge/Symfony/Routing/IriConverterTest.php

@@ -284,6 +284,21 @@ public function testGetItemFromIriBadIdentifierException()
         $this->assertEquals($converter->getItemFromIri('/users/3', ['fetch_data' => true]), $item);
     }
 
+    public function testNoIdentifiersException()
+    {
+        $this->expectException(InvalidArgumentException::class);
+        $this->expectExceptionMessage('No identifiers defined for resource of type "\App\Entity\Sample"');
+
+        $routeNameResolverProphecy = $this->prophesize(RouteNameResolverInterface::class);
+        $routerProphecy = $this->prophesize(RouterInterface::class);
+
+        $converter = $this->getIriConverter($routerProphecy, $routeNameResolverProphecy, null);
+
+        $method = new \ReflectionMethod(IriConverter::class, 'generateIdentifiersUrl');
+        $method->setAccessible(true);
+        $method->invoke($converter, [], '\App\Entity\Sample');
+    }
+
     /**
      * @group legacy
      * @expectedDeprecation Not injecting "ApiPlatform\Core\Api\IdentifiersExtractorInterface" is deprecated since API Platform 2.1 and will not be possible anymore in API Platform 3