cli: Add test for unknown field in identity doc

Add a test to confirm that the identity can still be deserialized when an
unknown field is added.

Signed-off-by: Fintan Halpenny <fintan.halpenny@gmail.com>
X-Clacks-Overhead: GNU Terry Pratchett

radicle-cli/examples/rad-id-unknown-field.md

@@ -0,0 +1,47 @@
+The payloads in the identity document are extensible and arbitrary fields can be
+added. Here we will add an emoji alias for the heartwood project:
+
+```
+$ rad id update --title "Add emoji alias" --description "Adding alias field" --payload xyz.radicle.project alias '"❤️🪵"'
+✓ Identity revision 05100d3f0a73b9373681677158615a53ba51940e created
+╭────────────────────────────────────────────────────────────────────────╮
+│ Title    Add emoji alias                                               │
+│ Revision 05100d3f0a73b9373681677158615a53ba51940e                      │
+│ Blob     a0f421c928dcfc6eca129fc2ea1f50877de7dc20                      │
+│ Author   did:key:z6MknSLrJoTcukLrE435hVNQT4JUhbvWLX4kUzqkEStBU8Vi      │
+│ State    accepted                                                      │
+│ Quorum   yes                                                           │
+│                                                                        │
+│ Adding alias field                                                     │
+├────────────────────────────────────────────────────────────────────────┤
+│ ✓ did:key:z6MknSLrJoTcukLrE435hVNQT4JUhbvWLX4kUzqkEStBU8Vi alice (you) │
+╰────────────────────────────────────────────────────────────────────────╯
+
+@@ -1,13 +1,14 @@
+ {
+   "payload": {
+     "xyz.radicle.project": {
++      "alias": "❤️🪵",
+       "defaultBranch": "master",
+       "description": "Radicle Heartwood Protocol & Stack",
+       "name": "heartwood"
+     }
+   },
+   "delegates": [
+     "did:key:z6MknSLrJoTcukLrE435hVNQT4JUhbvWLX4kUzqkEStBU8Vi"
+   ],
+   "threshold": 1
+ }
+```
+
+We can see that the project payload still loads by using `rad ls` which will
+attempt to deserialize the payload:
+
+```
+$ rad ls
+╭───────────────────────────────────────────────────────────────────────────────────────────────────────────╮
+│ Name        RID                                 Visibility   Head      Description                        │
+├───────────────────────────────────────────────────────────────────────────────────────────────────────────┤
+│ heartwood   rad:z42hL2jL4XNk6K8oHQaSWfMgCL7ji   public       f2de534   Radicle Heartwood Protocol & Stack │
+╰───────────────────────────────────────────────────────────────────────────────────────────────────────────╯
+```

radicle-cli/tests/commands.rs

@@ -627,6 +627,35 @@ fn rad_id_conflict() {
         .unwrap();
 }
 
+#[test]
+fn rad_id_unknown_field() {
+    let mut environment = Environment::new();
+    let alice = environment.node(config::node("alice"));
+    let working = tempfile::tempdir().unwrap();
+    let working = working.path();
+
+    // Setup a test repository.
+    fixtures::repository(working.join("alice"));
+
+    test(
+        "examples/rad-init.md",
+        working.join("alice"),
+        Some(&alice.home),
+        [],
+    )
+    .unwrap();
+
+    let alice = alice.spawn();
+
+    test(
+        "examples/rad-id-unknown-field.md",
+        working.join("alice"),
+        Some(&alice.home),
+        [],
+    )
+    .unwrap();
+}
+
 #[test]
 fn rad_node_connect() {
     let mut environment = Environment::new();