diff --git a/Cargo.lock b/Cargo.lock
index 8d12bfc..31d28d7 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1,19 +1,9 @@
 # This file is automatically @generated by Cargo.
 # It is not intended for manual editing.
-[[package]]
-name = "addr2line"
-version = "0.14.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7c0929d69e78dd9bf5408269919fcbcaeb2e35e5d43e5815517cdc6a8e11a423"
-dependencies = [
- "gimli",
-]
-
 [[package]]
 name = "adduser"
 version = "0.1.0"
 dependencies = [
- "assert_cli",
  "chrono",
  "clap",
  "derive_builder",
@@ -23,14 +13,9 @@ dependencies = [
  "regex",
  "simplelog",
  "tempfile",
+ "test_bin",
 ]
 
-[[package]]
-name = "adler"
-version = "0.2.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ee2a4ec343196209d6594e19543ae87a39f96d5534d7174822a3ad825dd6ed7e"
-
 [[package]]
 name = "aho-corasick"
 version = "0.7.13"
@@ -40,20 +25,6 @@ dependencies = [
  "memchr",
 ]
 
-[[package]]
-name = "assert_cli"
-version = "0.6.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a29ab7c0ed62970beb0534d637a8688842506d0ff9157de83286dacd065c8149"
-dependencies = [
- "colored",
- "difference",
- "environment",
- "failure",
- "failure_derive",
- "serde_json",
-]
-
 [[package]]
 name = "atty"
 version = "0.2.14"
@@ -71,20 +42,6 @@ version = "1.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "cdb031dd78e28731d87d56cc8ffef4a8f36ca26c38fe2de700543e627f8a464a"
 
-[[package]]
-name = "backtrace"
-version = "0.3.54"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2baad346b2d4e94a24347adeee9c7a93f412ee94b9cc26e5b59dea23848e9f28"
-dependencies = [
- "addr2line",
- "cfg-if 1.0.0",
- "libc",
- "miniz_oxide",
- "object",
- "rustc-demangle",
-]
-
 [[package]]
 name = "bitflags"
 version = "1.2.1"
@@ -97,12 +54,6 @@ version = "0.1.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "4785bdd1c96b2a846b2bd7cc02e86b6b3dbf14e7e53446c4f54c92a361040822"
 
-[[package]]
-name = "cfg-if"
-version = "1.0.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "baf1de4339761588bc0619e3cbc0120ee582ebb74b53b4efbf79117bd2da40fd"
-
 [[package]]
 name = "chrono"
 version = "0.4.19"
@@ -148,17 +99,6 @@ dependencies = [
  "syn",
 ]
 
-[[package]]
-name = "colored"
-version = "1.9.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f4ffc801dacf156c5854b9df4f425a626539c3a6ef7893cc0c5084a23f0b6c59"
-dependencies = [
- "atty",
- "lazy_static",
- "winapi",
-]
-
 [[package]]
 name = "darling"
 version = "0.10.2"
@@ -219,12 +159,6 @@ dependencies = [
  "syn",
 ]
 
-[[package]]
-name = "difference"
-version = "2.0.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "524cbf6897b527295dff137cec09ecf3a05f4fddffd7dfcd1585403449e74198"
-
 [[package]]
 name = "env_logger"
 version = "0.8.1"
@@ -238,34 +172,6 @@ dependencies = [
  "termcolor",
 ]
 
-[[package]]
-name = "environment"
-version = "0.1.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1f4b14e20978669064c33b4c1e0fb4083412e40fe56cbea2eae80fd7591503ee"
-
-[[package]]
-name = "failure"
-version = "0.1.8"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d32e9bd16cc02eae7db7ef620b392808b89f6a5e16bb3497d159c6b92a0f4f86"
-dependencies = [
- "backtrace",
- "failure_derive",
-]
-
-[[package]]
-name = "failure_derive"
-version = "0.1.8"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "aa4da3c766cd7a0db8242e326e9e4e081edd567072893ed320008189715366a4"
-dependencies = [
- "proc-macro2",
- "quote",
- "syn",
- "synstructure",
-]
-
 [[package]]
 name = "fnv"
 version = "1.0.7"
@@ -278,17 +184,11 @@ version = "0.1.15"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "fc587bc0ec293155d5bfa6b9891ec18a1e330c234f896ea47fbada4cadbe47e6"
 dependencies = [
- "cfg-if 0.1.10",
+ "cfg-if",
  "libc",
  "wasi 0.9.0+wasi-snapshot-preview1",
 ]
 
-[[package]]
-name = "gimli"
-version = "0.23.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f6503fe142514ca4799d4c26297c4248239fe8838d827db6bd6065c6ed29a6ce"
-
 [[package]]
 name = "hashbrown"
 version = "0.9.1"
@@ -335,12 +235,6 @@ dependencies = [
  "hashbrown",
 ]
 
-[[package]]
-name = "itoa"
-version = "0.4.6"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "dc6f3ad7b9d11a0c00842ff8de1b60ee58661048eb8049ed33c73594f359d7e6"
-
 [[package]]
 name = "lazy_static"
 version = "1.4.0"
@@ -359,7 +253,7 @@ version = "0.4.11"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "4fabed175da42fed1fa0746b0ea71f412aa9d35e76e95e59b192c64b9dc2bf8b"
 dependencies = [
- "cfg-if 0.1.10",
+ "cfg-if",
 ]
 
 [[package]]
@@ -368,16 +262,6 @@ version = "2.3.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "3728d817d99e5ac407411fa471ff9800a778d88a24685968b36824eaf4bee400"
 
-[[package]]
-name = "miniz_oxide"
-version = "0.4.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0f2d26ec3309788e423cfbf68ad1800f061638098d76a83681af979dc4eda19d"
-dependencies = [
- "adler",
- "autocfg",
-]
-
 [[package]]
 name = "num-integer"
 version = "0.1.43"
@@ -397,12 +281,6 @@ dependencies = [
  "autocfg",
 ]
 
-[[package]]
-name = "object"
-version = "0.22.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8d3b63360ec3cb337817c2dbd47ab4a0f170d285d8e5a2064600f3def1402397"
-
 [[package]]
 name = "os_str_bytes"
 version = "2.4.0"
@@ -531,35 +409,6 @@ dependencies = [
  "winapi",
 ]
 
-[[package]]
-name = "rustc-demangle"
-version = "0.1.18"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6e3bad0ee36814ca07d7968269dd4b7ec89ec2da10c4bb613928d3077083c232"
-
-[[package]]
-name = "ryu"
-version = "1.0.5"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "71d301d4193d031abdd79ff7e3dd721168a9572ef3fe51a1517aba235bd8f86e"
-
-[[package]]
-name = "serde"
-version = "1.0.117"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b88fa983de7720629c9387e9f517353ed404164b1e482c970a90c1a4aaf7dc1a"
-
-[[package]]
-name = "serde_json"
-version = "1.0.59"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "dcac07dbffa1c65e7f816ab9eba78eb142c6d44410f4eeba1e26e4f5dfa56b95"
-dependencies = [
- "itoa",
- "ryu",
- "serde",
-]
-
 [[package]]
 name = "simplelog"
 version = "0.8.0"
@@ -594,25 +443,13 @@ dependencies = [
  "unicode-xid",
 ]
 
-[[package]]
-name = "synstructure"
-version = "0.12.4"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b834f2d66f734cb897113e34aaff2f1ab4719ca946f9a7358dba8f8064148701"
-dependencies = [
- "proc-macro2",
- "quote",
- "syn",
- "unicode-xid",
-]
-
 [[package]]
 name = "tempfile"
 version = "3.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7a6e24d9338a0a5be79593e2fa15a648add6138caa803e2d5bc782c371732ca9"
 dependencies = [
- "cfg-if 0.1.10",
+ "cfg-if",
  "libc",
  "rand",
  "redox_syscall",
@@ -629,6 +466,12 @@ dependencies = [
  "winapi-util",
 ]
 
+[[package]]
+name = "test_bin"
+version = "0.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1937bab04b0bd0f2c19628d3408fb6dd78faf5aa60f4bdb03212507a9b7314ba"
+
 [[package]]
 name = "textwrap"
 version = "0.12.1"
diff --git a/Cargo.toml b/Cargo.toml
index 057e55d..0750c6e 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -21,10 +21,11 @@ chrono = "0.4"
 env_logger = "0.8"
 derive_builder = "0.9"
 clap = "3.0.0-beta"
-assert_cli = "0.6"
 
 [dev-dependencies]
 tempfile = "3.1"
+test_bin= "0.3"
+
 
 # optimize for size at cost of compilation speed.
 [profile.release]
diff --git a/src/user/shadow_fields.rs b/src/user/shadow_fields.rs
index 115e39a..14629c3 100644
--- a/src/user/shadow_fields.rs
+++ b/src/user/shadow_fields.rs
@@ -26,6 +26,11 @@ impl Shadow {
     pub fn get_username(&self) -> &str {
         &self.username.username
     }
+
+    pub fn set_username(&mut self, username: crate::Username) {
+        self.username = username;
+    }
+
     #[must_use]
     pub fn get_password(&self) -> &str {
         &self.password.password
diff --git a/src/userlib/mod.rs b/src/userlib/mod.rs
index e504254..6e25227 100644
--- a/src/userlib/mod.rs
+++ b/src/userlib/mod.rs
@@ -231,10 +231,16 @@ impl UserDBWrite for UserDBLocal {
                 Err("Failed to create the user. A user with the same Name already exists".into())
             } else {
                 let opened = self.source_files.lock_all_get();
-                let (mut locked_p, mut _locked_s, mut _locked_g) =
+                let (mut locked_p, mut locked_s, mut _locked_g) =
                     opened.expect("failed to lock files!");
-                dbg!(&locked_p);
+                //dbg!(&locked_p);
                 locked_p.append(format!("{}", new_user))?;
+                if let Some(shadow) = new_user.get_shadow() {
+                    info!("Adding shadow entry {}", shadow);
+                    locked_s.append(format!("{}", shadow))?;
+                } else {
+                    warn!("Omitting shadow entry!")
+                }
                 assert!(self
                     .users
                     .insert(args.username.to_owned(), new_user)
diff --git a/tests/create_user_test.rs b/tests/create_user_test.rs
index cb214e4..d26d349 100644
--- a/tests/create_user_test.rs
+++ b/tests/create_user_test.rs
@@ -1,4 +1,5 @@
 extern crate adduser;
+extern crate test_bin;
 mod testfiles;
 
 #[test]
@@ -30,54 +31,93 @@ fn test_create_user_function() {
             .build()
             .unwrap(),
     );
-    let pf2 = fs::read_to_string(&p.path).unwrap();
+    let password_file_string = fs::read_to_string(&p.path).unwrap();
+    let shadow_file_string = fs::read_to_string(&p.path).unwrap();
     assert_eq!(user_res.unwrap().get_username().unwrap(), "test2");
     let pflines = pf.lines();
-    let pflines2 = pf2.lines();
+    let pflines2 = password_file_string.lines();
     for (l1, l2) in pflines.zip(pflines2) {
         dbg!(l1, l2);
         assert!(l1 == l2);
     }
-    assert!(pf2.lines().last().unwrap().starts_with("test2"));
+    assert!(password_file_string
+        .lines()
+        .last()
+        .unwrap()
+        .starts_with("test2"));
+    assert!(shadow_file_string
+        .lines()
+        .last()
+        .unwrap()
+        .starts_with("test2"));
 }
 #[test]
 fn test_create_user_binary() {
     use testfiles::Fixture;
 
-    use adduser::api::UserDBWrite;
-    use adduser::api::UserRead;
     use std::fs;
 
     let p = Fixture::copy("passwd");
     let s = Fixture::copy("shadow");
     let g = Fixture::copy("group");
 
-    dbg!(&p, &s, &g);
+    //dbg!(&p, &s, &g);
 
-    let pf = fs::read_to_string(&p.path).unwrap();
+    let passwd_string = fs::read_to_string(&p.path).unwrap();
+    let passwd_lines = passwd_string.lines();
+    let shadow_string = fs::read_to_string(&s.path).unwrap();
+    let shadow_lines = shadow_string.lines();
 
-    let mf = adduser::Files {
-        passwd: Some(p.path.clone()),
-        shadow: Some(s.path),
-        group: Some(g.path),
-    };
-
-    let mut db = adduser::UserDBLocal::load_files(mf).unwrap();
-
-    let user_res: Result<&adduser::User, adduser::UserLibError> = db.new_user(
-        adduser::api::CreateUserArgs::builder()
-            .username("test2")
-            // .delete_home(adduser::api::DeleteHome::Delete)
-            .build()
-            .unwrap(),
+    let out = test_bin::get_test_bin("create_user")
+        .args(&[
+            "testuser3",
+            "-p",
+            p.path.to_str().unwrap(),
+            "-s",
+            s.path.to_str().unwrap(),
+            "-g",
+            g.path.to_str().unwrap(),
+        ])
+        .output()
+        .expect("Failed to run the command");
+    println!(
+        "The output after running: {}",
+        String::from_utf8_lossy(&out.stdout)
     );
-    let pf2 = fs::read_to_string(&p.path).unwrap();
-    assert_eq!(user_res.unwrap().get_username().unwrap(), "test2");
-    let pflines = pf.lines();
-    let pflines2 = pf2.lines();
-    for (l1, l2) in pflines.zip(pflines2) {
-        dbg!(l1, l2);
+    println!(
+        "The error after running: {}",
+        String::from_utf8_lossy(&out.stderr)
+    );
+    assert_eq!(String::from_utf8_lossy(&out.stdout), "");
+    assert_eq!(String::from_utf8_lossy(&out.stderr), "");
+
+    let passwd_string_after = fs::read_to_string(&p.path).unwrap();
+    let passwd_lines_after = passwd_string_after.lines();
+    let shadow_string_after = fs::read_to_string(&s.path).unwrap();
+    let shadow_lines_after = shadow_string_after.lines();
+    for (l1, l2) in passwd_lines.zip(passwd_lines_after) {
+        //dbg!(l1, l2);
         assert!(l1 == l2);
     }
-    assert!(pf2.lines().last().unwrap().starts_with("test2"));
+    assert_eq!(
+        passwd_string_after
+            .lines()
+            .last()
+            .unwrap()
+            .starts_with("testuser3"),
+        true
+    );
+    //dbg!(&shadow_string_after);
+    for (l1, l2) in shadow_lines.zip(shadow_lines_after) {
+        //dbg!(l1, l2);
+        assert!(l1 == l2);
+    }
+    assert_eq!(
+        shadow_string_after
+            .lines()
+            .last()
+            .unwrap()
+            .starts_with("testuser3"),
+        true
+    );
 }