From 4951b1b0f9a20ab50d4e534806b1ee22ee9d2c6c Mon Sep 17 00:00:00 2001
From: Maurizio <hello@lemaur.me>
Date: Thu, 17 Aug 2023 20:48:18 +0200
Subject: [PATCH] feat: add `toBeSnakeCase`

---
 src/Mixins/Expectation.php              | 12 ++++++++++++
 tests/Features/Expect/toBeSnakeCase.php | 23 +++++++++++++++++++++++
 2 files changed, 35 insertions(+)
 create mode 100644 tests/Features/Expect/toBeSnakeCase.php

diff --git a/src/Mixins/Expectation.php b/src/Mixins/Expectation.php
index 56e1da09..d128d30b 100644
--- a/src/Mixins/Expectation.php
+++ b/src/Mixins/Expectation.php
@@ -1009,4 +1009,16 @@ final class Expectation
 
         return $this;
     }
+
+    /**
+     * Asserts that the value is snake_case.
+     *
+     * @return self<TValue>
+     */
+    public function toBeSnakeCase(string $message = ''): self
+    {
+        Assert::assertTrue((bool) preg_match('/^[\p{Ll}_]+$/u', (string) $this->value), $message);
+
+        return $this;
+    }
 }
diff --git a/tests/Features/Expect/toBeSnakeCase.php b/tests/Features/Expect/toBeSnakeCase.php
new file mode 100644
index 00000000..121f9e51
--- /dev/null
+++ b/tests/Features/Expect/toBeSnakeCase.php
@@ -0,0 +1,23 @@
+<?php
+
+use PHPUnit\Framework\ExpectationFailedException;
+
+test('pass', function () {
+    expect('abc')->toBeSnakeCase();
+    expect('abc_def')->toBeSnakeCase();
+    expect('abc-def')->not->toBeSnakeCase();
+    expect('abcDef')->not->toBeSnakeCase();
+    expect('AbcDef')->not->toBeSnakeCase();
+});
+
+test('failures', function () {
+    expect('Abc')->toBeSnakeCase();
+})->throws(ExpectationFailedException::class);
+
+test('failures with custom message', function () {
+    expect('Abc')->toBeSnakeCase('oh no!');
+})->throws(ExpectationFailedException::class, 'oh no!');
+
+test('not failures', function () {
+    expect('abc_def')->not->toBeSnakeCase();
+})->throws(ExpectationFailedException::class);