diff --git a/lib/Feed/Exception.php b/lib/Feed/Exception.php
index 3cab2c9..b9d2056 100644
--- a/lib/Feed/Exception.php
+++ b/lib/Feed/Exception.php
@@ -29,10 +29,7 @@ class Exception extends \JKingWeb\Arsse\AbstractException {
                     $msgID = "tooManyRedirects";
                     break;
                 default:
-                    $c = $e->getCode();
-                    if ($c >= 400 && $c < 600) {
-                        $msgID = "transmissionError";
-                    }
+                    $msgID = "transmissionError";
             }
         } elseif ($e instanceof TooManyRedirectsException) {
             $msgID = "maxRedirect";
diff --git a/tests/cases/CLI/TestCLI.php b/tests/cases/CLI/TestCLI.php
index 6056912..ef302f2 100644
--- a/tests/cases/CLI/TestCLI.php
+++ b/tests/cases/CLI/TestCLI.php
@@ -6,6 +6,7 @@
 declare(strict_types=1);
 namespace JKingWeb\Arsse\TestCase\CLI;
 
+use GuzzleHttp\Exception\ClientException;
 use JKingWeb\Arsse\Arsse;
 use JKingWeb\Arsse\Conf;
 use JKingWeb\Arsse\User;
@@ -81,7 +82,7 @@ class TestCLI extends \JKingWeb\Arsse\Test\AbstractTest {
     public function testRefreshAFeed(string $cmd, int $exitStatus, string $output): void {
         Arsse::$db = \Phake::mock(Database::class);
         \Phake::when(Arsse::$db)->feedUpdate(1, true)->thenReturn(true);
-        \Phake::when(Arsse::$db)->feedUpdate(2, true)->thenThrow(new \JKingWeb\Arsse\Feed\Exception("http://example.com/", new \PicoFeed\Client\InvalidUrlException));
+        \Phake::when(Arsse::$db)->feedUpdate(2, true)->thenThrow(new \JKingWeb\Arsse\Feed\Exception("http://example.com/", $this->mockGuzzleException(ClientException::class, "", 404)));
         $this->assertConsole($this->cli, $cmd, $exitStatus, $output);
         \Phake::verify($this->cli)->loadConf;
         \Phake::verify(Arsse::$db)->feedUpdate;
diff --git a/tests/cases/Database/SeriesSubscription.php b/tests/cases/Database/SeriesSubscription.php
index 434427e..a89319e 100644
--- a/tests/cases/Database/SeriesSubscription.php
+++ b/tests/cases/Database/SeriesSubscription.php
@@ -6,6 +6,7 @@
 declare(strict_types=1);
 namespace JKingWeb\Arsse\TestCase\Database;
 
+use GuzzleHttp\Exception\ClientException;
 use JKingWeb\Arsse\Arsse;
 use JKingWeb\Arsse\Test\Database;
 use JKingWeb\Arsse\Feed\Exception as FeedException;
@@ -200,7 +201,7 @@ trait SeriesSubscription {
     public function testAddASubscriptionToAnInvalidFeed(): void {
         $url = "http://example.org/feed1";
         $feedID = $this->nextID("arsse_feeds");
-        \Phake::when(Arsse::$db)->feedUpdate->thenThrow(new FeedException($url, new \PicoFeed\Client\InvalidUrlException()));
+        \Phake::when(Arsse::$db)->feedUpdate->thenThrow(new FeedException($url, $this->mockGuzzleException(ClientException::class, "", 404)));
         $this->assertException("invalidUrl", "Feed");
         try {
             Arsse::$db->subscriptionAdd($this->user, $url, "", "", false);
diff --git a/tests/cases/Feed/TestFetching.php b/tests/cases/Feed/TestFetching.php
index 4ac7ece..3ce3e8d 100644
--- a/tests/cases/Feed/TestFetching.php
+++ b/tests/cases/Feed/TestFetching.php
@@ -58,7 +58,7 @@ class TestFetching extends \JKingWeb\Arsse\Test\AbstractTest {
     }
 
     public function testHandleAnOverlyLargeFeed(): void {
-        $this->markTestIncomplete();
+        $this->markTestIncomplete("The nicolus/picofeed library does not implement miniflux/picofeed's max-size setting");
         Arsse::$conf->fetchSizeLimit = 512;
         $this->assertException("maxSize", "Feed");
         new Feed(null, $this->base."Fetching/TooLarge");
diff --git a/tests/cases/REST/TinyTinyRSS/TestAPI.php b/tests/cases/REST/TinyTinyRSS/TestAPI.php
index 8f94c76..0db7f1f 100644
--- a/tests/cases/REST/TinyTinyRSS/TestAPI.php
+++ b/tests/cases/REST/TinyTinyRSS/TestAPI.php
@@ -6,6 +6,7 @@
 declare(strict_types=1);
 namespace JKingWeb\Arsse\TestCase\REST\TinyTinyRSS;
 
+use GuzzleHttp\Exception\ClientException;
 use JKingWeb\Arsse\Arsse;
 use JKingWeb\Arsse\User;
 use JKingWeb\Arsse\Database;
@@ -785,12 +786,12 @@ LONG_STRING;
         ];
         $out = [
             ['code' => 1, 'feed_id' => 2],
-            ['code' => 5, 'message' => (new \JKingWeb\Arsse\Feed\Exception("http://example.com/1", new \PicoFeed\Client\UnauthorizedException()))->getMessage()],
+            ['code' => 5, 'message' => (new \JKingWeb\Arsse\Feed\Exception("http://example.com/1", $this->mockGuzzleException(ClientException::class, "", 401)))->getMessage()],
             ['code' => 1, 'feed_id' => 0],
             ['code' => 0, 'feed_id' => 3],
             ['code' => 0, 'feed_id' => 1],
             ['code' => 3, 'message' => (new \JKingWeb\Arsse\Feed\Exception("http://localhost:8000/Feed/Discovery/Invalid", new \PicoFeed\Reader\SubscriptionNotFoundException()))->getMessage()],
-            ['code' => 2, 'message' => (new \JKingWeb\Arsse\Feed\Exception("http://example.com/6", new \PicoFeed\Client\InvalidUrlException()))->getMessage()],
+            ['code' => 2, 'message' => (new \JKingWeb\Arsse\Feed\Exception("http://example.com/6", $this->mockGuzzleException(ClientException::class, "", 404)))->getMessage()],
             ['code' => 6, 'message' => (new \JKingWeb\Arsse\Feed\Exception("http://example.com/7", new \PicoFeed\Parser\MalformedXmlException()))->getMessage()],
             ['code' => 1, 'feed_id' => 4],
             ['code' => 0, 'feed_id' => 4],
@@ -802,12 +803,12 @@ LONG_STRING;
             ['id' => 4, 'url' => "http://example.com/9"],
         ];
         \Phake::when(Arsse::$db)->subscriptionAdd(...$db[0])->thenReturn(2);
-        \Phake::when(Arsse::$db)->subscriptionAdd(...$db[1])->thenThrow(new \JKingWeb\Arsse\Feed\Exception("http://example.com/1", new \PicoFeed\Client\UnauthorizedException()));
+        \Phake::when(Arsse::$db)->subscriptionAdd(...$db[1])->thenThrow(new \JKingWeb\Arsse\Feed\Exception("http://example.com/1", $this->mockGuzzleException(ClientException::class, "", 401)));
         \Phake::when(Arsse::$db)->subscriptionAdd(...$db[2])->thenReturn(2);
         \Phake::when(Arsse::$db)->subscriptionAdd(...$db[3])->thenThrow(new ExceptionInput("constraintViolation"));
         \Phake::when(Arsse::$db)->subscriptionAdd(...$db[4])->thenThrow(new ExceptionInput("constraintViolation"));
         \Phake::when(Arsse::$db)->subscriptionAdd(...$db[5])->thenThrow(new ExceptionInput("constraintViolation"));
-        \Phake::when(Arsse::$db)->subscriptionAdd(...$db[6])->thenThrow(new \JKingWeb\Arsse\Feed\Exception("http://example.com/6", new \PicoFeed\Client\InvalidUrlException()));
+        \Phake::when(Arsse::$db)->subscriptionAdd(...$db[6])->thenThrow(new \JKingWeb\Arsse\Feed\Exception("http://example.com/6", $this->mockGuzzleException(ClientException::class, "", 404)));
         \Phake::when(Arsse::$db)->subscriptionAdd(...$db[7])->thenThrow(new \JKingWeb\Arsse\Feed\Exception("http://example.com/7", new \PicoFeed\Parser\MalformedXmlException()));
         \Phake::when(Arsse::$db)->subscriptionAdd(...$db[8])->thenReturn(4);
         \Phake::when(Arsse::$db)->subscriptionAdd(...$db[9])->thenThrow(new ExceptionInput("constraintViolation"));
diff --git a/tests/lib/AbstractTest.php b/tests/lib/AbstractTest.php
index 0a553d1..1a03278 100644
--- a/tests/lib/AbstractTest.php
+++ b/tests/lib/AbstractTest.php
@@ -6,6 +6,8 @@
 declare(strict_types=1);
 namespace JKingWeb\Arsse\Test;
 
+use GuzzleHttp\Exception\GuzzleException;
+use GuzzleHttp\Exception\RequestException;
 use JKingWeb\Arsse\Exception;
 use JKingWeb\Arsse\Arsse;
 use JKingWeb\Arsse\Conf;
@@ -325,4 +327,16 @@ abstract class AbstractTest extends \PHPUnit\Framework\TestCase {
             $this->assertArraySubset($expected, [], false, "Expectations not in result set.");
         }
     }
+
+    /** Guzzle's exception classes require some fairly complicated construction; this abstracts it all away so that only message and code need be supplied  */
+    protected function mockGuzzleException(string $class, ?string $message = null, ?int $code = null, ?\Throwable $e = null): GuzzleException {
+        if (is_a($class, RequestException::class, true)) {
+            $req = \Phake::mock(RequestInterface::class);
+            $res = \Phake::mock(ResponseInterface::class);
+            \Phake::when($res)->getStatusCode->thenReturn($code ?? 0);
+            return new $class($message ?? "", $req, $res, $e);
+        } else {
+            return new $class($message ?? "", $code ?? 0, $e);
+        }
+    }
 }