Enhancement: Assert that StringProvider::arbitrary() provides all kin…

…ds of values

test/Unit/DataProvider/StringProviderTest.php

@@ -42,6 +42,11 @@ public function testArbitraryReturnsGeneratorThatProvidesStringsThatAreNeitherEm
             'string-arbitrary-word' => Util\DataProvider\Specification\Closure::create(static function (string $value): bool {
                 return '' !== $value && '' !== \trim($value);
             }),
+            'string-blank-carriage-return' => Util\DataProvider\Specification\Identical::create("\r"),
+            'string-blank-line-feed' => Util\DataProvider\Specification\Identical::create("\n"),
+            'string-blank-space' => Util\DataProvider\Specification\Identical::create(' '),
+            'string-blank-tab' => Util\DataProvider\Specification\Identical::create("\t"),
+            'string-empty' => Util\DataProvider\Specification\Identical::create(''),
             'string-untrimmed-carriage-return' => Util\DataProvider\Specification\Pattern::create('/^\r{1,5}\w+\r{1,5}$/'),
             'string-untrimmed-line-feed' => Util\DataProvider\Specification\Pattern::create('/^\n{1,5}\w+\n{1,5}$/'),
             'string-untrimmed-space' => Util\DataProvider\Specification\Pattern::create('/^\s{1,5}\w+\s{1,5}$/'),