minor #50062 [HttpClient] Improve MockHttpClient exception message (fancyweb)

This PR was merged into the 6.3 branch.

Discussion
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[HttpClient] Improve MockHttpClient exception message

| Q             | A
| ------------- | ---
| Branch?       | 6.3
| Bug fix?      | no
| New feature?  | no
| Deprecations? | no
| Tickets       | symfony/symfony#49874 (comment)
| License       | MIT
| Doc PR        | -

When using `MockHttpClient`, if there are more requests done on the client than the passed available responses, the exception message is misleading.

~Targeting 5.4 since it only changes the exception message 😅~

Commits
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bd5a4caef4 [HttpClient] Improve MockHttpClient exception message

Author: nicolas-grekas

MockHttpClient.php

@@ -69,7 +69,7 @@ public function request(string $method, string $url, array $options = []): Respo
         } elseif (\is_callable($this->responseFactory)) {
             $response = ($this->responseFactory)($method, $url, $options);
         } elseif (!$this->responseFactory->valid()) {
-            throw new TransportException('The response factory iterator passed to MockHttpClient is empty.');
+            throw new TransportException($this->requestsCount ? 'No more response left in the response factory iterator passed to MockHttpClient: the number of requests exceeds the number of responses.' : 'The response factory iterator passed to MockHttpClient is empty.');
         } else {
             $responseFactory = $this->responseFactory->current();
             $response = \is_callable($responseFactory) ? $responseFactory($method, $url, $options) : $responseFactory;

Tests/MockHttpClientTest.php

@@ -554,4 +554,23 @@ public function testCancelingMockResponseExecutesOnProgressWithUpdatedInfo()
 
         $this->assertTrue($canceled);
     }
+
+    public function testEmptyResponseFactory()
+    {
+        $this->expectException(TransportException::class);
+        $this->expectExceptionMessage('The response factory iterator passed to MockHttpClient is empty.');
+
+        $client = new MockHttpClient([]);
+        $client->request('GET', 'https://example.com');
+    }
+
+    public function testMoreRequestsThanResponseFactoryResponses()
+    {
+        $this->expectException(TransportException::class);
+        $this->expectExceptionMessage('No more response left in the response factory iterator passed to MockHttpClient: the number of requests exceeds the number of responses.');
+
+        $client = new MockHttpClient([new MockResponse()]);
+        $client->request('GET', 'https://example.com');
+        $client->request('GET', 'https://example.com');
+    }
 }