Improve error message for failed domain DNS

We need another PHPUnit version for PHP 5.5.

.travis.yml

@@ -11,12 +11,10 @@ cache:
     - vendor
 
 install:
-  - phpenv config-rm xdebug.ini
-  - composer self-update
+  - phpenv config-rm xdebug.ini || true
   - composer config --global discard-changes true
-  - if [[ ${TRAVIS_PHP_VERSION:0:3} == "5.5" ]]; then composer require --dev --no-update phpunit/phpunit ^4; fi
-  - composer require satooshi/php-coveralls dev-master --dev --no-update
-  - composer update --ignore-platform-reqs
+  - composer update
+  - composer require satooshi/php-coveralls dev-master --dev
   - composer show --installed
 
 script:

composer.json

@@ -22,7 +22,7 @@
         "symfony/yaml": "^3.0"
     },
     "require-dev": {
-        "phpunit/phpunit": "^5",
+        "phpunit/phpunit": "^4|^5",
         "friendsofphp/php-cs-fixer": "^1.9",
         "macfja/phar-builder": "^0.2.5"
     },

src/Commands/Issue.php

@@ -194,7 +194,13 @@ class Issue implements Command {
         }
 
         if (!empty($errors)) {
-            throw new AcmeException("Couldn't resolve the following domains to an IPv4 nor IPv6 record: " . implode(", ", array_keys($errors)));
+            $failedDomains = implode(", ", array_keys($errors));
+            $reasons = implode("\n\n", array_map(function ($exception) {
+                /** @var \Exception|\Throwable $exception */
+                return get_class($exception) . ": " . $exception->getMessage();
+            }, $errors));
+
+            throw new AcmeException("Couldn't resolve the following domains to an IPv4 nor IPv6 record: {$failedDomains}\n\n{$reasons}");
         }
     }
 

src/Commands/Setup.php

@@ -3,6 +3,7 @@
 namespace Kelunik\AcmeClient\Commands;
 
 use Amp\CoroutineResult;
+use Amp\Dns\NoRecordException;
 use Amp\Dns\Record;
 use Amp\Dns\ResolutionException;
 use InvalidArgumentException;
@@ -80,8 +81,10 @@ class Setup implements Command {
 
         try {
             yield \Amp\Dns\query($host, Record::MX);
-        } catch (ResolutionException $e) {
+        } catch (NoRecordException $e) {
             throw new AcmeException("No MX record defined for '{$host}'");
+        } catch (ResolutionException $e) {
+            throw new AcmeException("Dns query for an MX record on '{$host}' failed for the following reason: " . $e->getMessage(), null, $e);
         }
     }