diff --git a/src/util/cli.rs b/src/util/cli.rs
index d6e7685..975df7c 100644
--- a/src/util/cli.rs
+++ b/src/util/cli.rs
@@ -7,7 +7,7 @@ pub fn to_file_size(size: u64) -> String {
     if size >= 512.0 {
         size /= 1024.0;
     } else {
-        return format!("{:.0} Bytes", size);
+        return format!("{:.0} Byte", size);
     }
     if size >= 512.0 {
         size /= 1024.0;
@@ -80,3 +80,52 @@ impl<T: Iterator> Iterator for ProgressIter<T> {
         }
     }
 }
+
+
+mod tests {
+
+    #[allow(unused_imports)]
+    use super::*;
+
+    #[test]
+    fn test_to_file_size() {
+        assert_eq!("0 Byte", to_file_size(0));
+        assert_eq!("1 Byte", to_file_size(1));
+        assert_eq!("15 Byte", to_file_size(15));
+        assert_eq!("456 Byte", to_file_size(456));
+        assert_eq!("0.7 KiB", to_file_size(670));
+        assert_eq!("237.0 KiB", to_file_size(242670));
+        assert_eq!("442.5 KiB", to_file_size(453170));
+        assert_eq!("0.7 MiB", to_file_size(753170));
+        assert_eq!("12.2 MiB", to_file_size(12753170));
+        assert_eq!("222.0 MiB", to_file_size(232753170));
+        assert_eq!("5.1 GiB", to_file_size(5435353170));
+        assert_eq!("291.1 GiB", to_file_size(312534553170));
+        assert_eq!("3.9 TiB", to_file_size(4312534553170));
+    }
+
+    #[test]
+    fn test_to_speed() {
+        assert_eq!("0 Byte/s", to_speed(0, 1.0));
+        assert_eq!("100 Byte/s", to_speed(100, 1.0));
+        assert_eq!("1.0 KiB/s", to_speed(100, 0.1));
+        assert_eq!("10 Byte/s", to_speed(100, 10.0));
+        assert_eq!("237.0 KiB/s", to_speed(242670, 1.0));
+        assert_eq!("0.7 MiB/s", to_speed(753170, 1.0));
+        assert_eq!("222.0 MiB/s", to_speed(232753170, 1.0));
+        assert_eq!("291.1 GiB/s", to_speed(312534553170, 1.0));
+        assert_eq!("3.9 TiB/s", to_speed(4312534553170, 1.0));
+    }
+
+    #[test]
+    fn test_to_duration() {
+        assert_eq!("0:00:00.0", to_duration(0.0));
+        assert_eq!("0:00:00.1", to_duration(0.1));
+        assert_eq!("0:00:01.0", to_duration(1.0));
+        assert_eq!("0:01:00.0", to_duration(60.0));
+        assert_eq!("1:00:00.0", to_duration(3600.0));
+        assert_eq!("2:02:02.2", to_duration(7322.2));
+    }
+
+
+}
diff --git a/src/util/compression.rs b/src/util/compression.rs
index 9297308..1cca334 100644
--- a/src/util/compression.rs
+++ b/src/util/compression.rs
@@ -274,3 +274,122 @@ impl Drop for CompressionStream {
         unsafe { squash_object_unref(self.stream as *mut libc::c_void); }
     }
 }
+
+
+mod tests {
+
+    #[allow(unused_imports)]
+    use super::*;
+
+    #[test]
+    fn test_parse() {
+        let method = Compression::from_string("deflate/1").unwrap();
+        assert_eq!(("deflate", 1), (method.name(), method.level()));
+        let method = Compression::from_string("zlib/2").unwrap();
+        assert_eq!(("deflate", 2), (method.name(), method.level()));
+        let method = Compression::from_string("gzip/3").unwrap();
+        assert_eq!(("deflate", 3), (method.name(), method.level()));
+        let method = Compression::from_string("brotli/1").unwrap();
+        assert_eq!(("brotli", 1), (method.name(), method.level()));
+        let method = Compression::from_string("lzma/1").unwrap();
+        assert_eq!(("lzma", 1), (method.name(), method.level()));
+        let method = Compression::from_string("lzma2/2").unwrap();
+        assert_eq!(("lzma", 2), (method.name(), method.level()));
+        let method = Compression::from_string("xz/3").unwrap();
+        assert_eq!(("lzma", 3), (method.name(), method.level()));
+        let method = Compression::from_string("lz4/1").unwrap();
+        assert_eq!(("lz4", 1), (method.name(), method.level()));
+    }
+
+    #[test]
+    fn test_to_string() {
+        assert_eq!("brotli/1", Compression::from_string("brotli/1").unwrap().to_string());
+        assert_eq!("deflate/1", Compression::from_string("gzip/1").unwrap().to_string());
+    }
+
+    #[allow(dead_code, needless_range_loop)]
+    fn test_data(n: usize) -> Vec<u8> {
+        let mut input = vec![0; n];
+        for i in 0..input.len() {
+            input[i] = (i * i * i) as u8;
+        }
+        input
+    }
+
+    #[allow(dead_code)]
+    fn test_compression(method: &str, min_lvl: u8, max_lvl: u8) {
+        let input = test_data(16*1024);
+        for i in min_lvl..max_lvl+1 {
+            let method = Compression::from_string(&format!("{}/{}", method, i)).unwrap();
+            println!("{}", method.to_string());
+            let compressed = method.compress(&input).unwrap();
+            let decompressed = method.decompress(&compressed).unwrap();
+            assert_eq!(input.len(), decompressed.len());
+            for i in 0..input.len() {
+                assert_eq!(input[i], decompressed[i]);
+            }
+        }
+    }
+
+    #[test]
+    fn test_compression_deflate() {
+        test_compression("deflate", 1, 9)
+    }
+
+    #[test]
+    fn test_compression_brotli() {
+        test_compression("brotli", 1, 11)
+    }
+
+    #[test]
+    fn test_compression_lzma() {
+        test_compression("lzma", 1, 9)
+    }
+
+    #[test]
+    fn test_compression_lz4() {
+        test_compression("lz4", 1, 11)
+    }
+
+    #[allow(dead_code)]
+    fn test_stream_compression(method: &str, min_lvl: u8, max_lvl: u8) {
+        let input = test_data(512*1024);
+        for i in min_lvl..max_lvl+1 {
+            let method = Compression::from_string(&format!("{}/{}", method, i)).unwrap();
+            println!("{}", method.to_string());
+            let mut compressor = method.compress_stream().unwrap();
+            let mut compressed = Vec::with_capacity(input.len());
+            compressor.process(&input, &mut compressed).unwrap();
+            compressor.finish(&mut compressed).unwrap();
+            let mut decompressor = method.decompress_stream().unwrap();
+            let mut decompressed = Vec::with_capacity(input.len());
+            decompressor.process(&compressed, &mut decompressed).unwrap();
+            decompressor.finish(&mut decompressed).unwrap();
+            assert_eq!(input.len(), decompressed.len());
+            for i in 0..input.len() {
+                assert_eq!(input[i], decompressed[i]);
+            }
+        }
+    }
+
+    #[test]
+    fn test_stream_compression_deflate() {
+        test_stream_compression("deflate", 1, 9)
+    }
+
+    #[test]
+    fn test_stream_compression_brotli() {
+        test_stream_compression("brotli", 1, 11)
+    }
+
+    #[test]
+    fn test_stream_compression_lzma() {
+        test_stream_compression("lzma", 1, 9)
+    }
+
+    #[test]
+    fn test_stream_compression_lz4() {
+        test_stream_compression("lz4", 1, 11)
+    }
+
+}