From 0b9a55b4e47ccf90a59bc377f28d0a8c56ee8952 Mon Sep 17 00:00:00 2001
From: Simon Cropp <simon.cropp@gmail.com>
Date: Fri, 14 Jun 2024 19:39:22 +1000
Subject: [PATCH] more AgainstBadExtension

---
 src/Verify/FilePair.cs                      | 19 ++++++++++++++-----
 src/Verify/Guard.cs                         |  5 +++++
 src/Verify/Verifier/InnerVerifier_Stream.cs |  1 +
 3 files changed, 20 insertions(+), 5 deletions(-)

diff --git a/src/Verify/FilePair.cs b/src/Verify/FilePair.cs
index 7ef9ca2002..ea01bb43ee 100644
--- a/src/Verify/FilePair.cs
+++ b/src/Verify/FilePair.cs
@@ -1,9 +1,18 @@
 namespace VerifyTests;
 
-public readonly struct FilePair(string extension, string receivedPath, string verifiedPath)
+public readonly struct FilePair
 {
-    public string Extension { get; } = extension;
-    public string ReceivedPath { get; } = receivedPath;
-    public string VerifiedPath { get; } = verifiedPath;
-    public bool IsText { get; } = FileExtensions.IsTextExtension(extension);
+    public FilePair(string extension, string receivedPath, string verifiedPath)
+    {
+        Guard.AgainstBadExtension(extension);
+        Extension = extension;
+        ReceivedPath = receivedPath;
+        VerifiedPath = verifiedPath;
+        IsText = FileExtensions.IsTextExtension(extension);
+    }
+
+    public string Extension { get; }
+    public string ReceivedPath { get; }
+    public string VerifiedPath { get; }
+    public bool IsText { get; }
 }
\ No newline at end of file
diff --git a/src/Verify/Guard.cs b/src/Verify/Guard.cs
index 226801e0d8..2a7844663c 100644
--- a/src/Verify/Guard.cs
+++ b/src/Verify/Guard.cs
@@ -144,5 +144,10 @@ public static void AgainstBadExtension(string value, [CallerArgumentExpression("
         {
             throw new ArgumentException("Must not start with a period ('.').", argumentName);
         }
+
+        if (value.Contains('\\') || value.Contains('/'))
+        {
+            throw new ArgumentException("Must not contain a directory separator.", argumentName);
+        }
     }
 }
\ No newline at end of file
diff --git a/src/Verify/Verifier/InnerVerifier_Stream.cs b/src/Verify/Verifier/InnerVerifier_Stream.cs
index 815349bac5..f3909fe5c1 100644
--- a/src/Verify/Verifier/InnerVerifier_Stream.cs
+++ b/src/Verify/Verifier/InnerVerifier_Stream.cs
@@ -73,6 +73,7 @@ public Task<VerifyResult> VerifyStream(Stream? stream, object? info) =>
 
     public async Task<VerifyResult> VerifyStream(Stream? stream, string extension, object? info)
     {
+        Guard.AgainstBadExtension(extension);
         if (stream is null)
         {
             if (info is null)