cob: Improve stability of test setup

We employ various tricks to ensure that tests are reproducible.
In this case, having stable commit ids allows us to test specific
traversal orders of a COB history in cases of concurrent updates.

radicle-cob/Cargo.toml

@@ -12,6 +12,11 @@ edition = "2021"
 license = "MIT OR Apache-2.0"
 keywords = ["radicle", "cob", "cobs"]
 
+[features]
+default = []
+# Only used for testing. Ensures that commit ids are stable.
+stable-commit-ids = []
+
 [dependencies]
 fastrand = { version = "2.0.0" }
 log = { version = "0.4.17" }

radicle-cob/src/backend/git/change.rs

@@ -261,6 +261,7 @@ fn write_commit(
 ) -> Result<(Oid, Timestamp), error::Create> {
     let trailers: Vec<OwnedTrailer> = vec![trailers::ResourceCommitTrailer::from(resource).into()];
     let author = repo.signature()?;
+    #[allow(unused_variables)]
     let timestamp = author.when().seconds();
 
     let mut headers = Headers::new();
@@ -273,6 +274,15 @@ fn write_commit(
     );
     let author = Author::try_from(&author)?;
 
+    #[cfg(feature = "stable-commit-ids")]
+    // Ensures the commit id doesn't change on every run.
+    let (author, timestamp) = (
+        Author {
+            time: git_ext::author::Time::new(1514817556, 0),
+            ..author
+        },
+        1514817556,
+    );
     #[cfg(debug_assertions)]
     let (author, timestamp) = if let Ok(s) = std::env::var(crate::git::RAD_COMMIT_TIME) {
         // SAFETY: It's ok to panic here, since this is only enabled in debug mode.

radicle/Cargo.toml

@@ -64,3 +64,8 @@ qcheck = { version = "1", default-features = false }
 path = "../radicle-crypto"
 version = "0"
 features = ["test"]
+
+[dev-dependencies.radicle-cob]
+path = "../radicle-cob"
+version = "0"
+features = ["stable-commit-ids"]

radicle/src/test.rs

@@ -92,15 +92,13 @@ pub mod setup {
         fn default() -> Self {
             let root = tempfile::tempdir().unwrap();
 
-            Self::new(root)
+            Self::new(root, MockSigner::default())
         }
     }
 
     impl Node {
-        pub fn new(root: impl AsRef<Path>) -> Self {
+        pub fn new(root: impl AsRef<Path>, signer: MockSigner) -> Self {
             let root = root.as_ref().to_path_buf();
-            let mut rng = fastrand::Rng::new();
-            let signer = MockSigner::new(&mut rng);
             let home = root.join("home");
             let paths = Home::new(home.as_path()).unwrap();
             let storage = Storage::open(paths.storage()).unwrap();
@@ -138,10 +136,12 @@ pub mod setup {
     }
 
     impl NodeRepo {
+        #[track_caller]
         pub fn fetch(&self, from: &Node) -> Vec<RefUpdate> {
             super::fetch(&self.repo, from.signer.public_key(), Namespaces::All).unwrap()
         }
 
+        #[track_caller]
         pub fn checkout(&self) -> &NodeRepoCheckout {
             self.checkout.as_ref().unwrap()
         }
@@ -240,9 +240,9 @@ pub mod setup {
     impl Default for Network {
         fn default() -> Self {
             let tmp = tempfile::tempdir().unwrap();
-            let alice = Node::new(tmp.path().join("alice"));
+            let alice = Node::new(tmp.path().join("alice"), MockSigner::from_seed([!0; 32]));
-            let mut bob = Node::new(tmp.path().join("bob"));
+            let mut bob = Node::new(tmp.path().join("bob"), MockSigner::from_seed([!1; 32]));
-            let mut eve = Node::new(tmp.path().join("eve"));
+            let mut eve = Node::new(tmp.path().join("eve"), MockSigner::from_seed([!2; 32]));
             let repo = alice.project();
             let rid = repo.id;
 

radicle/src/test/fixtures.rs

@@ -10,7 +10,7 @@ use crate::storage::git::Storage;
 use crate::storage::refs::SignedRefs;
 
 /// The birth of the radicle project, January 1st, 2018.
-const RADICLE_EPOCH: i64 = 1514817556;
+pub const RADICLE_EPOCH: i64 = 1514817556;
 
 /// Create a new storage with a project.
 pub fn storage<P: AsRef<Path>, G: Signer>(path: P, signer: &G) -> Result<Storage, rad::InitError> {