diff --git a/src/cli.rs b/src/cli.rs
index 722023f..efc0d13 100644
--- a/src/cli.rs
+++ b/src/cli.rs
@@ -1,6 +1,6 @@
 use clap::Parser;
 
-#[derive(Debug, Parser)]
+#[derive(Debug, PartialEq, Parser)]
 #[command(name = "onx")]
 #[command(version)]
 #[command(about)]
diff --git a/src/lib.rs b/src/lib.rs
index d2e8b59..fe87acc 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -56,3 +56,74 @@ pub fn render_cli_error(err: &CliError, pretty: bool) -> String {
   render_error(err, pretty)
     .unwrap_or_else(|_| "{\"error\":{\"code\":1,\"message\":\"Unexpected error.\"}}".to_string())
 }
+
+#[cfg(test)]
+mod tests {
+  use super::*;
+
+  #[test]
+  fn parse_cli_from_when_called_with_valid_program_name_it_should_return_cli() {
+    let result = parse_cli_from(["test"]);
+
+    assert_eq!(
+      result,
+      Ok(Cli {
+        api_key: None,
+        base_url: None,
+        pretty: false
+      })
+    );
+  }
+
+  #[test]
+  fn parse_cli_from_when_called_with_unknown_flag_it_should_return_usage_error() {
+    let result = parse_cli_from(["test", "--bogus"]);
+
+    assert!(result.is_err());
+    assert_eq!(result.as_ref().unwrap_err().code, 2);
+    assert!(
+      result
+        .as_ref()
+        .unwrap_err()
+        .message
+        .contains("unexpected argument")
+    );
+  }
+
+  #[test]
+  fn parse_cli_from_when_called_with_help_flag_it_should_return_info_with_code_0() {
+    let result = parse_cli_from(["test", "--help"]);
+
+    let err = result.unwrap_err();
+
+    assert_eq!(err.code, 0);
+    assert!(err.message.contains(env!("CARGO_PKG_DESCRIPTION")));
+  }
+
+  #[test]
+  fn parse_cli_from_when_called_with_version_flag_it_should_return_info_with_code_0() {
+    let result = parse_cli_from(["test", "--version"]);
+
+    let err = result.unwrap_err();
+
+    assert_eq!(err.code, 0);
+    assert!(err.message.contains(env!("CARGO_PKG_NAME")));
+    assert!(err.message.contains(env!("CARGO_PKG_VERSION")));
+  }
+
+  #[test]
+  fn render_cli_error_when_called_with_error_it_should_render_json() {
+    let error = CliError {
+      code: 1,
+      message: String::from("Something went wrong"),
+    };
+
+    let result = render_cli_error(&error, false);
+
+    assert_eq!(
+      result,
+      r#"{"error":{"code":1,"message":"Something went wrong"}}"#
+    );
+  }
+}
+
diff --git a/src/output.rs b/src/output.rs
index 67497ae..20fa183 100644
--- a/src/output.rs
+++ b/src/output.rs
@@ -31,3 +31,49 @@ pub fn render_error(err: &CliError, pretty: bool) -> CliResult<String> {
 
   render_json(&envelope, pretty)
 }
+
+#[cfg(test)]
+mod tests {
+  use super::*;
+  use serde_json::json;
+
+  #[test]
+  fn render_json_when_called_without_pretty_it_should_print_value() {
+    let data = json!({
+        "name": "Stevan",
+    });
+
+    let result = render_json(&data, false);
+
+    let expected = Ok(String::from(r#"{"name":"Stevan"}"#));
+    assert_eq!(result, expected);
+  }
+
+  #[test]
+  fn render_json_when_called_with_pretty_it_should_pretty_print_value() {
+    let data = json!({
+        "name": "Stevan",
+    });
+
+    let result = render_json(&data, true);
+
+    let expected = Ok(String::from("{\n  \"name\": \"Stevan\"\n}"));
+    assert_eq!(result, expected);
+  }
+
+  #[test]
+  fn render_error_when_called_with_error_it_should_render_properly() {
+    let error = CliError {
+      code: 1,
+      message: String::from("This is a test"),
+    };
+
+    let result = render_error(&error, false);
+
+    let expected = Ok(String::from(
+      r#"{"error":{"code":1,"message":"This is a test"}}"#,
+    ));
+    assert_eq!(result, expected);
+  }
+}
+