From 0c91ec8eddb22fdae8dcd3ad7408edee8632a48a Mon Sep 17 00:00:00 2001
From: Yuta Nagamiya <y.nagamiya@gmail.com>
Date: Mon, 1 Aug 2022 03:10:21 +0900
Subject: [PATCH] Add static factory methods for true and false specifications

---
 src/AbstractSpecification.php  | 16 ++++++++++++++++
 src/SpecificationInterface.php | 14 ++++++++++++++
 2 files changed, 30 insertions(+)

diff --git a/src/AbstractSpecification.php b/src/AbstractSpecification.php
index 87ec504..3b31d5a 100644
--- a/src/AbstractSpecification.php
+++ b/src/AbstractSpecification.php
@@ -24,6 +24,22 @@ abstract class AbstractSpecification implements SpecificationInterface
      */
     abstract public function isSatisfiedBy($candidate): bool;
 
+    /**
+     * {@inheritdoc}
+     */
+    public static function true(): SpecificationInterface
+    {
+        return TrueSpecification::getInstance();
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public static function false(): SpecificationInterface
+    {
+        return FalseSpecification::getInstance();
+    }
+
     /**
      * {@inheritdoc}
      */
diff --git a/src/SpecificationInterface.php b/src/SpecificationInterface.php
index 2e171b4..d950c45 100644
--- a/src/SpecificationInterface.php
+++ b/src/SpecificationInterface.php
@@ -26,6 +26,20 @@ interface SpecificationInterface
      */
     public function isSatisfiedBy($candidate): bool;
 
+    /**
+     * Create a new specification that is always true.
+     *
+     * @return SpecificationInterface<T> a new specification
+     */
+    public static function true(): SpecificationInterface;
+
+    /**
+     * Create a new specification that is always false.
+     *
+     * @return SpecificationInterface<T> a new specification
+     */
+    public static function false(): SpecificationInterface;
+
     /**
      * Create a new specification that is the AND operation of this specification and another specification.
      *