Add test-util features to hide test utilities

We had a handful of items intended for use exclusively in tests that
were marked `pub` so that targets like `monolithic_integration_test` can
use them, but tagged `#[doc(hidden)]` because they aren't part of the
proper public interface to any component of Janus. We now instead hide
those test utilities behind a new `test-util` feature defined on crates
`janus_core`, `janus_client` and `janus_server`. We could also have
moved items to the `test_util` crate but there's something to be said
for having e.g. the code that inserts tasks into the datastore be right
next to all the other datastore code, instead of `test_util/lib.rs`
becoming a dumping ground of items unrelated to each other save that
they are used in tests. Additionally, if we ever want to "promote" any
of these `test_util` items to being used in production configurations,
that's a simple matter of deleting a `#[cfg(feature = "test-util")]`
instead of having to move a function and annihilate its git history.

Resolves #141

janus_client/Cargo.toml

@@ -21,6 +21,7 @@ url = "2.2.2"
 
 [dev-dependencies]
 assert_matches = "1"
+janus_core = { path = "../janus_core", features = ["test-util"]}
 janus_test_util = { path = "../test_util" }
 mockito = "0.31.0"
 tracing-log = "0.1.3"

janus_core/Cargo.toml

@@ -11,6 +11,7 @@ rust-version = "1.58"
 
 [features]
 database = ["bytes", "postgres-protocol", "postgres-types"]
+test-util = []
 
 [dependencies]
 anyhow = "1"

janus_core/src/hpke.rs

@@ -170,8 +170,7 @@ pub fn open(
         .map_err(Into::into)
 }
 
-// This is public to allow use in integration tests.
-#[doc(hidden)]
+#[cfg(feature = "test-util")]
 pub mod test_util {
     use crate::{
         hpke::HpkePrivateKey,

janus_server/Cargo.toml

@@ -11,6 +11,7 @@ tokio-console = ["console-subscriber"]
 jaeger = ["tracing-opentelemetry", "opentelemetry-jaeger"]
 otlp = ["tracing-opentelemetry", "opentelemetry-otlp", "opentelemetry-semantic-conventions", "tonic"]
 prometheus = ["opentelemetry-prometheus", "dep:prometheus"]
+test-util = []
 
 [dependencies]
 anyhow = "1"
@@ -62,6 +63,7 @@ warp = { version = "^0.3", features = ["tls"] }
 assert_matches = "1"
 hex = { version = "0.4.3", features = ["serde"] }
 hyper = "0.14.19"
+janus_server = { path = ".", features = ["test-util"] }
 janus_test_util = { path = "../test_util" }
 lazy_static = "1"
 libc = "0.2.126"

janus_server/src/datastore.rs

@@ -138,8 +138,8 @@ pub struct Transaction<'a, C: Clock> {
 }
 
 impl<C: Clock> Transaction<'_, C> {
-    // This is pub to be used in integration tests
-    #[doc(hidden)]
+    /// Allows tests to insert tasks into the datastore.
+    #[cfg(feature = "test-util")]
     #[tracing::instrument(skip(self), err)]
     pub async fn put_task(&self, task: &Task) -> Result<(), Error> {
         let aggregator_role = AggregatorRole::from_role(task.role)?;
@@ -817,10 +817,9 @@ impl<C: Clock> Transaction<'_, C> {
             .transpose()
     }
 
-    /// get_aggregation_jobs_for_task_id returns all aggregation jobs for a given task ID. It is
-    /// intended for use in tests.
+    /// get_aggregation_jobs_for_task_id returns all aggregation jobs for a given task ID.
+    #[cfg(feature = "test-util")]
     #[tracing::instrument(skip(self), err)]
-    #[doc(hidden)]
     pub async fn get_aggregation_jobs_for_task_id<const L: usize, A: vdaf::Aggregator<L>>(
         &self,
         task_id: TaskId,

janus_server/src/message.rs

@@ -456,7 +456,7 @@ impl Decode for CollectResp {
     }
 }
 
-#[doc(hidden)]
+#[cfg(feature = "test-util")]
 pub mod test_util {
     use super::{Nonce, TaskId};
     use janus_core::message::{Report, Time};

janus_server/src/task.rs

@@ -301,8 +301,7 @@ impl Task {
     }
 }
 
-// This is public to allow use in integration tests.
-#[doc(hidden)]
+#[cfg(feature = "test-util")]
 pub mod test_util {
     use std::iter;
 

monolithic_integration_test/Cargo.toml

@@ -12,7 +12,7 @@ deadpool-postgres = "0.10.1"
 futures = "0.3.21"
 janus_core = { path = "../janus_core" }
 janus_client = { path = "../janus_client" }
-janus_server = { path = "../janus_server" }
+janus_server = { path = "../janus_server", features = ["test-util"] }
 lazy_static = "1"
 prio = "0.8.0"
 rand = "0.8"