extracted Expectations to a CoreExpectation class

src/Exceptions/ExpectationNotFoundException.php

@@ -0,0 +1,17 @@
+<?php
+
+namespace Pest\Exceptions;
+
+use InvalidArgumentException;
+
+/**
+ * @internal
+ */
+final class ExpectationNotFoundException extends InvalidArgumentException
+{
+    public function __construct(string $expectationName)
+    {
+        parent::__construct(sprintf("Impossible to find [%s] expectation", $expectationName));
+    }
+
+}