tests: add some basic tests for rendering outputs

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);
+  }
+}
+