Add support for enums in error message (#292)

src/Assert.php

@@ -2087,6 +2087,10 @@ protected static function valueToString($value)
                 return \get_class($value).': '.self::valueToString($value->format('c'));
             }
 
+            if (\function_exists('enum_exists') && \enum_exists(\get_class($value))) {
+                return \get_class($value).'::'.$value->name;
+            }
+
             return \get_class($value);
         }
 

tests/AssertTest.php

@@ -833,6 +833,22 @@ public function testResourceOfTypeCustomMessage(): void
 
         Assert::resource(null, 'curl', 'I want a resource of type %2$s. Got: %s');
     }
+
+    public function testEnumAssertionErrorMessage(): void
+    {
+        $enumIntroductionVersion = 80100;
+
+        if (PHP_VERSION_ID < $enumIntroductionVersion) {
+            $this->markTestSkipped(sprintf('This test requires php %s or upper.', $enumIntroductionVersion));
+        }
+
+        require_once 'DummyEnum.php';
+
+        $this->expectException('\InvalidArgumentException');
+        $this->expectExceptionMessage('Expected null. Got: Webmozart\Assert\Tests\TestEnum::CaseName');
+
+        Assert::null(TestEnum::CaseName, 'Expected null. Got: %s');
+    }
 }
 
 /**

tests/DummyEnum.php

@@ -0,0 +1,9 @@
+<?php
+
+namespace Webmozart\Assert\Tests;
+
+// The filename must be different from the class name to be ignored by composer PSR-4 autoloading rules
+enum TestEnum
+{
+    case CaseName;
+}