Remove unused variable from test

Address code review feedback: remove unused testFile variable

Co-authored-by: adamhathcock <527620+adamhathcock@users.noreply.github.com>

src/SharpCompress/Factories/ArjFactory.cs

@@ -28,12 +28,19 @@ namespace SharpCompress.Factories
             int bufferSize = ReaderOptions.DefaultBufferSize
         )
         {
-            var arjHeader = new ArjMainHeader(new ArchiveEncoding());
-            if (arjHeader.Read(stream) == null)
+            try
+            {
+                var arjHeader = new ArjMainHeader(new ArchiveEncoding());
+                if (arjHeader.Read(stream) == null)
+                {
+                    return false;
+                }
+                return true;
+            }
+            catch
             {
                 return false;
             }
-            return true;
         }
 
         public IReader OpenReader(Stream stream, ReaderOptions? options) =>

tests/SharpCompress.Test/ArchiveTests.cs

@@ -654,4 +654,31 @@ public class ArchiveTests : ReaderTests
             Assert.Equal(3, archive.Entries.Count());
         }
     }
+
+    [Fact]
+    public void ArchiveFactory_IsArchive_NonArchiveFile_ShouldReturnFalse()
+    {
+        // Test that ArchiveFactory.IsArchive returns false instead of throwing
+        // when called on a non-archive file (regression test for issue #1060)
+        using (var stream = new MemoryStream(new byte[] { 0x00, 0x01, 0x02, 0x03, 0x04 }))
+        {
+            var result = ArchiveFactory.IsArchive(stream, out var type);
+            Assert.False(result);
+            Assert.Null(type);
+        }
+    }
+
+    [Fact]
+    public void ArchiveFactory_IsArchive_ValidArchive_ShouldReturnTrue()
+    {
+        // Test that ArchiveFactory.IsArchive correctly identifies valid archives
+        var testArchive = Path.Combine(TEST_ARCHIVES_PATH, "Zip.bzip2.noEmptyDirs.zip");
+
+        using (var stream = File.OpenRead(testArchive))
+        {
+            var result = ArchiveFactory.IsArchive(stream, out var type);
+            Assert.True(result);
+            Assert.Equal(ArchiveType.Zip, type);
+        }
+    }
 }