From 4b87dd5c5c24f7356c24578f0117ff4048737da4 Mon Sep 17 00:00:00 2001
From: Max Wipfli <mail@maxwipfli.ch>
Date: Thu, 1 Jul 2021 20:00:07 +0200
Subject: [PATCH] Tests: Add test for String::find with empty needle

This adds a test case for String::find and String::find_all with empty
needles. The expected behavior is in line with what the C++ standard
library (and other languages standard libraries) expect.
---
 Tests/AK/TestString.cpp | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/Tests/AK/TestString.cpp b/Tests/AK/TestString.cpp
index 01c6368c58..418027a27b 100644
--- a/Tests/AK/TestString.cpp
+++ b/Tests/AK/TestString.cpp
@@ -271,3 +271,14 @@ TEST_CASE(find)
     EXPECT_EQ(a.find('b', 4), Optional<size_t> { 6 });
     EXPECT_EQ(a.find('b', 9), Optional<size_t> {});
 }
+
+TEST_CASE(find_with_empty_needle)
+{
+    String string = "";
+    EXPECT_EQ(string.find(""sv), 0u);
+    EXPECT_EQ(string.find_all(""sv), (Vector<size_t> { 0u }));
+
+    string = "abc";
+    EXPECT_EQ(string.find(""sv), 0u);
+    EXPECT_EQ(string.find_all(""sv), (Vector<size_t> { 0u, 1u, 2u, 3u }));
+}