diff --git a/src/error.rs b/src/error.rs
index ee9e73b..5560315 100644
--- a/src/error.rs
+++ b/src/error.rs
@@ -2,7 +2,7 @@ use std::{fmt, path::PathBuf};
 
 use colored::Colorize;
 
-#[derive(Debug)]
+#[derive(PartialEq, Eq, Debug)]
 pub enum Error {
     UnknownExtensionError(String),
     MissingExtensionError(String),
diff --git a/src/test.rs b/src/test.rs
index 3f523d5..2dcabe4 100644
--- a/src/test.rs
+++ b/src/test.rs
@@ -1,8 +1,11 @@
+use std::{convert::TryFrom};
+
+
+
 #[cfg(test)]
 mod cli {
-    
-    use std::{convert::TryFrom};
 
+    use std::convert::TryFrom;
     use crate::cli::clap_app;
     use crate::cli::Command;
     use crate::file::File;
@@ -10,6 +13,7 @@ mod cli {
     use crate::extensions::CompressionExtension::*;
     use crate::error::OuchResult;
 
+
     #[test]
     fn decompress_files_into_folder() -> OuchResult<()> {
         let matches = clap_app().
@@ -40,7 +44,7 @@ mod cli {
     fn decompress_files() -> OuchResult<()> {
         let matches = clap_app().
         get_matches_from(
-            vec!["ouch", "-i", "file.zip"]
+            vec!["ouch", "-i", "file.zip", "file.tar"]
         );
         let command_from_matches = Command::try_from(matches)?;
 
@@ -53,6 +57,10 @@ mod cli {
                             "file.zip".into(),
                             Zip,
                         ),
+                        (
+                            "file.tar".into(),
+                            Tar,
+                        ),
                     ],
                 ),
                 output: None,
@@ -61,4 +69,51 @@ mod cli {
 
         Ok(())
     }
+
+    #[test]
+    fn compress_files() -> OuchResult<()> {
+        let matches = clap_app().
+        get_matches_from(
+            vec!["ouch", "-i", "file", "file2.jpeg", "file3.ok", "-o", "file.tar"]
+        );
+        let command_from_matches = Command::try_from(matches)?;
+
+        assert_eq!(
+            command_from_matches,
+            Command { command_type: Compression(vec!["file".into(), "file2.jpeg".into(), "file3.ok".into()]), output: Some(File::WithExtension(("file.tar".into(), Tar))) }
+        );
+
+        Ok(())
+    }
+}
+
+#[cfg(test)]
+mod cli_errors {
+    
+    use std::convert::TryFrom;
+
+    use crate::cli::clap_app;
+    use crate::cli::Command;
+    use crate::file::File;
+    use crate::cli::CommandType::*;
+    use crate::extensions::CompressionExtension::*;
+    use crate::error::OuchResult;
+    use crate::error::Error;
+
+
+    #[test]
+    fn compress_files() -> OuchResult<()> {
+        let matches = clap_app().
+        get_matches_from(
+            vec!["ouch", "-i", "a_file", "file2.jpeg", "file3.ok"]
+        );
+        let res = Command::try_from(matches);
+
+        assert_eq!(
+            res,
+            Err(Error::InputsMustHaveBeenDecompressible("a_file".into()))
+        );
+
+        Ok(())
+    }
 }
\ No newline at end of file