diff --git a/tests/SharpCompress.Test/ArchiveTests.cs b/tests/SharpCompress.Test/ArchiveTests.cs
index 222319d5..e30052e4 100644
--- a/tests/SharpCompress.Test/ArchiveTests.cs
+++ b/tests/SharpCompress.Test/ArchiveTests.cs
@@ -91,7 +91,7 @@ public class ArchiveTests : ReaderTests
         testArchive = Path.Combine(TEST_ARCHIVES_PATH, testArchive);
         ArchiveStreamRead(
             ArchiveFactory.FindFactory<IArchiveFactory>(testArchive),
-            Path.GetExtension(testArchive).Substring(1),
+            Path.GetExtension(testArchive),
             readerOptions,
             testArchive
         );
@@ -139,8 +139,7 @@ public class ArchiveTests : ReaderTests
         string extension
     )
     {
-      extension.Should().BeOneOf(archiveFactory.GetSupportedExtensions());
-
+        ExtensionTest(extension, archiveFactory);
         foreach (var path in testArchives)
         {
             using (
@@ -299,11 +298,7 @@ public class ArchiveTests : ReaderTests
     {
         testArchive = Path.Combine(TEST_ARCHIVES_PATH, testArchive);
         archiveFactory ??= ArchiveFactory.FindFactory<IArchiveFactory>(testArchive);
-        string extension = Path.GetExtension(testArchive).Substring(1);
-        if (!int.TryParse(extension, out _) && "exe" != extension) //exclude parts
-        {
-           extension.Should().BeOneOf(archiveFactory.GetSupportedExtensions());
-        }
+        ExtensionTest(testArchive, archiveFactory);
         using (var archive = archiveFactory.OpenArchive(new FileInfo(testArchive), readerOptions))
         {
             foreach (var entry in archive.Entries.Where(entry => !entry.IsDirectory))
@@ -317,6 +312,15 @@ public class ArchiveTests : ReaderTests
         VerifyFiles();
     }
 
+    private void ExtensionTest(string fullPath, IArchiveFactory archiveFactory)
+    {
+        var extension = Path.GetExtension(fullPath).Substring(1);
+        if (!int.TryParse(extension, out _) && "exe" != extension) //exclude parts
+        {
+            extension.Should().BeOneOf(archiveFactory.GetSupportedExtensions());
+        }
+    }
+
     protected void ArchiveFileSkip(
         string testArchive,
         string fileOrder,
diff --git a/tests/SharpCompress.Test/SevenZip/SevenZipArchiveTests.cs b/tests/SharpCompress.Test/SevenZip/SevenZipArchiveTests.cs
index da0a558b..c99ac558 100644
--- a/tests/SharpCompress.Test/SevenZip/SevenZipArchiveTests.cs
+++ b/tests/SharpCompress.Test/SevenZip/SevenZipArchiveTests.cs
@@ -83,10 +83,8 @@ public class SevenZipArchiveTests : ArchiveTests
 
     [Fact]
     public void SevenZipArchive_BZip2_Split() =>
-        Assert.Throws<InvalidOperationException>(() =>
-            ArchiveStreamRead(
-                ".7z",
-                null,
+        ArchiveStreamMultiRead(
+            null,
                 "Original.7z.001",
                 "Original.7z.002",
                 "Original.7z.003",
@@ -94,8 +92,7 @@ public class SevenZipArchiveTests : ArchiveTests
                 "Original.7z.005",
                 "Original.7z.006",
                 "Original.7z.007"
-            )
-        );
+            );
 
     //Same as archive as Original.7z.001 ... 007 files without the root directory 'Original\' in the archive - this caused the verify to fail
     [Fact]
@@ -150,17 +147,14 @@ public class SevenZipArchiveTests : ArchiveTests
 
     [Fact]
     public void SevenZipArchive_ZSTD_Split() =>
-        Assert.Throws<InvalidOperationException>(() =>
-            ArchiveStreamRead(
-                ".7z",
-                null,
-                "7Zip.ZSTD.Split.7z.001",
-                "7Zip.ZSTD.Split.7z.002",
-                "7Zip.ZSTD.Split.7z.003",
-                "7Zip.ZSTD.Split.7z.004",
-                "7Zip.ZSTD.Split.7z.005",
-                "7Zip.ZSTD.Split.7z.006"
-            )
+        ArchiveStreamMultiRead(
+            null,
+            "7Zip.ZSTD.Split.7z.001",
+            "7Zip.ZSTD.Split.7z.002",
+            "7Zip.ZSTD.Split.7z.003",
+            "7Zip.ZSTD.Split.7z.004",
+            "7Zip.ZSTD.Split.7z.005",
+            "7Zip.ZSTD.Split.7z.006"
         );
 
     [Fact]