Implement assertEmpty extension

Author: ondrejmirtes

src/Type/PHPUnit/Assert/AssertTypeSpecifyingExtensionHelper.php

@@ -3,6 +3,8 @@
 namespace PHPStan\Type\PHPUnit\Assert;
 
 use Closure;
+use Countable;
+use EmptyIterator;
 use PhpParser\Node\Arg;
 use PhpParser\Node\Expr;
 use PhpParser\Node\Expr\BinaryOp\Identical;
@@ -156,6 +158,15 @@ private static function getExpressionResolvers(): array
 						new ConstFetch(new Name('null'))
 					);
 				},
+				'Empty' => static function (Scope $scope, Arg $actual): Expr\BinaryOp\BooleanOr {
+					return new Expr\BinaryOp\BooleanOr(
+						new Instanceof_($actual->value, new Name(EmptyIterator::class)),
+						new Expr\BinaryOp\BooleanOr(
+							new Instanceof_($actual->value, new Name(Countable::class)),
+							new Expr\Empty_($actual->value)
+						)
+					);
+				},
 				'IsArray' => static function (Scope $scope, Arg $actual): FuncCall {
 					return new FuncCall(new Name('is_array'), [$actual]);
 				},

tests/Type/PHPUnit/data/assert-function.php

@@ -4,6 +4,7 @@
 
 use function PHPStan\Testing\assertType;
 use function PHPUnit\Framework\assertArrayHasKey;
+use function PHPUnit\Framework\assertEmpty;
 use function PHPUnit\Framework\assertInstanceOf;
 use function PHPUnit\Framework\assertObjectHasAttribute;
 
@@ -36,4 +37,10 @@ public function objectHasAttribute(object $a): void
 		assertType("object&hasProperty(property)", $a);
 	}
 
+	public function testEmpty($a): void
+	{
+		assertEmpty($a);
+		assertType("0|0.0|''|'0'|array{}|Countable|EmptyIterator|false|null", $a);
+	}
+
 }