diff --git a/src/DiffEngineViewer.Tests/IpcTests.List.verified.txt b/src/DiffEngineViewer.Tests/IpcTests.List.verified.txt
index f1351e5b..2c61dfe8 100644
--- a/src/DiffEngineViewer.Tests/IpcTests.List.verified.txt
+++ b/src/DiffEngineViewer.Tests/IpcTests.List.verified.txt
@@ -1,13 +1,13 @@
-{
+{
   Ok: true,
   Items: [
     {
       Key: sampletests.cs|42,
-      Name: SampleTests.cs:42
+      Name: sampletests.cs:42
     },
     {
       Key: othertests.cs|7,
-      Name: OtherTests.cs:7
+      Name: othertests.cs:7
     }
   ]
 }
\ No newline at end of file
diff --git a/src/DiffEngineViewer.Tests/IpcTests.cs b/src/DiffEngineViewer.Tests/IpcTests.cs
index 12179326..ccc8e8dd 100644
--- a/src/DiffEngineViewer.Tests/IpcTests.cs
+++ b/src/DiffEngineViewer.Tests/IpcTests.cs
@@ -72,12 +72,17 @@ public async Task SettleForAnUnknownKeyIsHarmless()
         await Assert.That(fixture.Host.State.Queue.Count).IsEqualTo(1);
     }
 
+    /// <summary>
+    /// Lower case paths, so the key is the same text on every platform: it folds case only where
+    /// the file system does, and what this is pinning is the shape of a listing rather than which
+    /// of those the runner is. InlineKey has a test per platform of its own.
+    /// </summary>
     [Test]
     public Task List()
     {
         using var fixture = new ServerFixture();
-        fixture.Send(Inline(Fixtures.Patch()));
-        fixture.Send(Inline(Fixtures.Patch("OtherTests.cs", 7, null, "new")));
+        fixture.Send(Inline(Fixtures.Patch("sampletests.cs")));
+        fixture.Send(Inline(Fixtures.Patch("othertests.cs", 7, null, "new")));
 
         return Verify(fixture.Send(new(ViewerVerb.List)));
     }
diff --git a/src/DiffEngineViewer.Tests/ViewerSessionTests.cs b/src/DiffEngineViewer.Tests/ViewerSessionTests.cs
index 89192ad5..8b8adf18 100644
--- a/src/DiffEngineViewer.Tests/ViewerSessionTests.cs
+++ b/src/DiffEngineViewer.Tests/ViewerSessionTests.cs
@@ -22,7 +22,13 @@ public async Task EnqueueReplacesSameKey()
         await Assert.That(state.Queue[0].LeftText).IsEqualTo("second");
     }
 
+    /// <summary>
+    /// Two paths differing only in case are one file here, so they are one entry. macOS runs this
+    /// one too — RunOn takes a single platform, and the folding itself has a test per platform in
+    /// ViewerProtocolTests.
+    /// </summary>
     [Test]
+    [RunOn(TUnit.Core.Enums.OS.Windows)]
     public async Task EnqueueKeyIgnoresPathCase()
     {
         var state = Fixtures.Inline(
@@ -32,6 +38,21 @@ public async Task EnqueueKeyIgnoresPathCase()
         await Assert.That(state.Queue.Count).IsEqualTo(1);
     }
 
+    /// <summary>
+    /// And two files where the file system says so, so two entries. One key for both meant the
+    /// second patch took over the first's entry and settling either settled both.
+    /// </summary>
+    [Test]
+    [RunOn(TUnit.Core.Enums.OS.Linux)]
+    public async Task EnqueueKeyKeepsPathCaseWhereTheFilesDo()
+    {
+        var state = Fixtures.Inline(
+            Fixtures.Patch("A.cs", 1, "\"a\"", "first"),
+            Fixtures.Patch("a.CS", 1, "\"a\"", "second"));
+
+        await Assert.That(state.Queue.Count).IsEqualTo(2);
+    }
+
     [Test]
     public async Task SettleRemovesMatchingItem()
     {