add some tests for the enum macro

tests/enum.rs

@@ -0,0 +1,59 @@
+use macroconf::ConfigEnum;
+use miniconf::{Error::Traversal, JsonCoreSlash, JsonPath, Traversal::Access, TreeKey};
+use rstest::*;
+use serde::{Deserialize, Serialize};
+use std::str::from_utf8;
+
+/// Description
+#[derive(Default, ConfigEnum, Serialize, Deserialize)]
+enum Test {
+    #[default]
+    Variant1,
+    Variant2,
+    Variant3,
+}
+
+#[test]
+fn nodes() {
+    let nodes = Test::nodes::<JsonPath<String>>()
+        .map(|p| p.unwrap().0.into_inner())
+        .collect::<Vec<_>>();
+    assert_eq!(
+        nodes,
+        vec![".value", ".variants", ".description", ".default"]
+    );
+}
+
+#[fixture]
+#[once]
+fn test() -> Test {
+    Test::Variant2
+}
+
+#[rstest]
+#[case("/", "\"Variant2\"")]
+#[case("/value", "\"Variant2\"")]
+#[case("/description", "\"Description\"")]
+#[case("/default", "\"Variant1\"")]
+#[case("/variants", "[\"Variant1\",\"Variant2\",\"Variant3\"]")]
+fn serialize(test: &Test, #[case] path: &str, #[case] expected: &str) {
+    let mut buffer = [0u8; 64];
+    let len = test.get_json(path, &mut buffer).unwrap();
+    assert_eq!(from_utf8(&buffer[..len]), Ok(expected));
+}
+
+#[rstest]
+#[case("/", Ok(10))]
+#[case("/value", Ok(10))]
+#[case("/variants", Err(Traversal(Access(0, "Cannot write limits"))))]
+#[case("/default", Err(Traversal(Access(0, "Cannot write limits"))))]
+#[case("/description", Err(Traversal(Access(0, "Cannot write limits"))))]
+fn deserialize(
+    #[case] path: &str,
+    #[case] expected: Result<usize, miniconf::Error<serde_json_core::de::Error>>,
+) {
+    let mut config = Test::Variant2;
+
+    let res = config.set_json(path, b"\"Variant3\"");
+    assert_eq!(res, expected);
+}