Add a not switch on Assert class

Author: Taluu

lib/Assert/AssertionChain.php

@@ -126,6 +126,13 @@ class AssertionChain
      */
     private $all = false;
 
+    /**
+     * Perform a negative assertion
+     *
+     * @var bool
+     */
+    private $not = false;
+
     /** @var string|Assertion Class to use for assertion calls */
     private $assertionClassName = 'Assert\Assertion';
 
@@ -174,6 +181,10 @@ public function __call($methodName, $args)
             }
         }
 
+        if ($this->not) {
+            $methodName = 'not'.$methodName;
+        }
+
         if ($this->all) {
             $methodName = 'all'.$methodName;
         }
@@ -195,6 +206,18 @@ public function all()
         return $this;
     }
 
+    /**
+     * Switch chain into negative mode
+     *
+     * @return \Assert\AssertionChain
+     */
+    public function not()
+    {
+        $this->not = true;
+
+        return $this;
+    }
+
     /**
      * Switch chain into mode allowing nulls, ignoring further assertions.
      *

tests/Assert/Tests/AssertionChainFunctionsTest.php

@@ -51,6 +51,11 @@ public function testThatAssertionChainFunctionsValidatesAllInputs()
         $this->assertInstanceOf(AssertionChain::class, \Assert\that([1, 2, 3])->all()->integer());
     }
 
+    public function testThatAssertionChainFunctionsValidateNegativeAssertions()
+    {
+        $this->assertInstanceOf(AssertionChain::class, \Assert\that('foo')->not()->isInstanceOf(\stdClass::class));
+    }
+
     public function testAssertionChainFunctionsThatAllShortcut()
     {
         $this->assertInstanceOf(AssertionChain::class, \Assert\thatAll([1, 2, 3])->integer());