New snapshot tests (#134)

* Changes project-related structures to use `BTreeMap` instead of `HashMap` for children to aid determiniusm
* Changes imfs-related structures to have total ordering and use `BTreeSet` instead of `HashSet`
* Upgrades dependencies to `bx_dom_weak`1.2.0 and rbx_xml 0.5.0 to aid in more determinism stuff
* Re-exposes the `RbxSession`'s root project via `root_project()`
* Implements `Default` for a couple things
* Tweaks visualization code to support visualizing trees not attached to an `RbxSession`
* Adds an ID-invariant comparison method for `rbx_tree` relying on previous determinism changes
* Adds a (disabled) test to start finding issues in the reconciler with regards to communicativity of snapshot application
* Adds a snapshot testing system that operates on `RbxTree` and associated metadata, which are committed in this change

server/tests/snapshot_snapshots.rs

@@ -0,0 +1,68 @@
+mod test_util;
+
+use std::path::Path;
+
+use pretty_assertions::assert_eq;
+
+use librojo::{
+    imfs::Imfs,
+    project::Project,
+    rbx_snapshot::{SnapshotContext, snapshot_project_tree},
+};
+
+use crate::test_util::{
+    snapshot::*,
+};
+
+macro_rules! generate_snapshot_tests {
+    ($($name: ident),*) => {
+        $(
+            paste::item! {
+                #[test]
+                fn [<snapshot_ $name>]() {
+                    let _ = env_logger::try_init();
+
+                    let tests_folder = Path::new(env!("CARGO_MANIFEST_DIR")).join("../test-projects");
+                    let project_folder = tests_folder.join(stringify!($name));
+                    run_snapshot_test(&project_folder);
+                }
+            }
+        )*
+    };
+}
+
+generate_snapshot_tests!(
+    empty,
+    multi_partition_game,
+    nested_partitions,
+    single_partition_game,
+    single_partition_model,
+    transmute_partition
+);
+
+fn run_snapshot_test(path: &Path) {
+    println!("Running snapshot from project: {}", path.display());
+
+    let project = Project::load_fuzzy(path)
+        .expect("Couldn't load project file for snapshot test");
+
+    let mut imfs = Imfs::new();
+    imfs.add_roots_from_project(&project)
+        .expect("Could not add IMFS roots to snapshot project");
+
+    let context = SnapshotContext {
+        plugin_context: None,
+    };
+
+    let mut snapshot = snapshot_project_tree(&context, &imfs, &project)
+        .expect("Could not generate snapshot for snapshot test");
+
+    if let Some(snapshot) = snapshot.as_mut() {
+        anonymize_snapshot(path, snapshot);
+    }
+
+    match read_expected_snapshot(path) {
+        Some(expected_snapshot) => assert_eq!(snapshot, expected_snapshot),
+        None => write_expected_snapshot(path, &snapshot),
+    }
+}