2 files changed, 83 insertions, 0 deletions
diff --git a/tests/Jellyfin.Extensions.Tests/PathHelperTests.cs b/tests/Jellyfin.Extensions.Tests/PathHelperTests.cs
new file mode 100644
index 0000000000..71fd853ba2
--- /dev/null
+++ b/tests/Jellyfin.Extensions.Tests/PathHelperTests.cs
@@ -0,0 +1,60 @@
+using System.IO;
+using Jellyfin.Extensions;
+using Xunit;
+
+namespace Jellyfin.Extensions.Tests
+{
+    public static class PathHelperTests
+    {
+        [Theory]
+        [InlineData("file.txt", "file.txt")]
+        [InlineData("sub/file.txt", "file.txt")]
+        [InlineData("../../etc/passwd", "passwd")]
+        public static void GetSafeLeafFileName_ReducesToLeaf(string input, string expected)
+        {
+            Assert.Equal(expected, PathHelper.GetSafeLeafFileName(input));
+        }
+
+        [Theory]
+        [InlineData(null)]
+        [InlineData("")]
+        [InlineData(".")]
+        [InlineData("..")]
+        public static void GetSafeLeafFileName_RejectsUnusableLeaf(string? input)
+        {
+            Assert.Null(PathHelper.GetSafeLeafFileName(input));
+        }
+
+        [Fact]
+        public static void IsContainedIn_ChildPath_ReturnsTrue()
+        {
+            var root = Path.Combine(Path.GetTempPath(), "root");
+            var child = Path.Combine(root, "sub", "file.txt");
+            Assert.True(PathHelper.IsContainedIn(root, child));
+        }
+
+        [Fact]
+        public static void IsContainedIn_RootItself_ReturnsTrue()
+        {
+            var root = Path.Combine(Path.GetTempPath(), "root");
+            Assert.True(PathHelper.IsContainedIn(root, root));
+        }
+
+        [Fact]
+        public static void IsContainedIn_TraversalEscape_ReturnsFalse()
+        {
+            var root = Path.Combine(Path.GetTempPath(), "root");
+            var escape = Path.Combine(root, "..", "..", "etc", "passwd");
+            Assert.False(PathHelper.IsContainedIn(root, escape));
+        }
+
+        [Fact]
+        public static void IsContainedIn_SiblingPrefixCollision_ReturnsFalse()
+        {
+            // "/var/data" must not be accepted as a parent of "/var/dataset".
+            var root = Path.Combine(Path.GetTempPath(), "data");
+            var sibling = Path.Combine(Path.GetTempPath(), "dataset", "file.txt");
+            Assert.False(PathHelper.IsContainedIn(root, sibling));
+        }
+    }
+}
diff --git a/tests/Jellyfin.Extensions.Tests/StringExtensionsTests.cs b/tests/Jellyfin.Extensions.Tests/StringExtensionsTests.cs
index 028f12afa7..0851570396 100644
--- a/tests/Jellyfin.Extensions.Tests/StringExtensionsTests.cs
+++ b/tests/Jellyfin.Extensions.Tests/StringExtensionsTests.cs
@@ -75,5 +75,28 @@ namespace Jellyfin.Extensions.Tests
             var result = str.AsSpan().RightPart(needle).ToString();
             Assert.Equal(expectedResult, result);
         }
+
+        [Theory]
+        [InlineData("", "")]
+        [InlineData("/media/movies/Film.mkv", "/media/movies/Film.mkv")]
+        [InlineData(@"C:\media\movies\Film.mkv", @"C:\media\movies\Film.mkv")]
+        [InlineData(@"/media/a""b.mkv", @"/media/a\""b.mkv")]
+        [InlineData(@"/media/a\""b.mkv", @"/media/a\\\""b.mkv")]
+        [InlineData(@"/media/a\\""b.mkv", @"/media/a\\\\\""b.mkv")]
+        [InlineData(@"/media/a\b""c.mkv", @"/media/a\b\""c.mkv")]
+        [InlineData(@"/media/trailing\", @"/media/trailing\\")]
+        [InlineData(@"/media/evil\"" -f lavfi -i sine .mkv", @"/media/evil\\\"" -f lavfi -i sine .mkv")]
+        public void EscapeProcessArgument_ValidInput_Corrects(string input, string expectedResult)
+        {
+            Assert.Equal(expectedResult, input.EscapeProcessArgument());
+        }
+
+        [Theory]
+        [InlineData("/media/movies/Film with spaces.mkv")]
+        [InlineData(@"C:\media\movies\Film.mkv")]
+        public void EscapeProcessArgument_NothingToEscape_ReturnsSameInstance(string input)
+        {
+            Assert.Same(input, input.EscapeProcessArgument());
+        }
     }
 }