             XCTFail("Unable to get test data.")
             return
         }
+
+        XCTAssertEqual(try TarContainer.formatOf(container: testData), .gnu)
 
         let entries = try TarContainer.open(container: testData)
 

            return
        }

        let entries = try TarContainer.open(container: testData)

        XCTAssertEqual(entries.count, 1)

            return
        }

        XCTAssertEqual(try TarContainer.formatOf(container: testData), .ustar)

        let entries = try TarContainer.open(container: testData)

        XCTAssertEqual(entries.count, 1)
