diff --git a/Cargo.lock b/Cargo.lock
index 21d28deb9..0fcebb018 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1281,7 +1281,6 @@ dependencies = [
  "assert_matches",
  "http",
  "janus_core",
- "janus_test_util",
  "mockito",
  "prio",
  "reqwest",
@@ -1302,6 +1301,7 @@ dependencies = [
  "base64",
  "bytes",
  "chrono",
+ "futures",
  "hex",
  "hpke-dispatch",
  "num_enum",
@@ -1314,6 +1314,9 @@ dependencies = [
  "serde_json",
  "thiserror",
  "tokio",
+ "tracing",
+ "tracing-log",
+ "tracing-subscriber",
 ]
 
 [[package]]
@@ -1337,7 +1340,6 @@ dependencies = [
  "itertools",
  "janus_core",
  "janus_server",
- "janus_test_util",
  "lazy_static",
  "libc",
  "mockito",
@@ -1377,23 +1379,6 @@ dependencies = [
  "warp",
 ]
 
-[[package]]
-name = "janus_test_util"
-version = "0.1.0"
-dependencies = [
- "assert_matches",
- "chrono",
- "futures",
- "janus_core",
- "prio",
- "rand",
- "ring",
- "tokio",
- "tracing",
- "tracing-log",
- "tracing-subscriber",
-]
-
 [[package]]
 name = "js-sys"
 version = "0.3.57"
@@ -1574,7 +1559,6 @@ dependencies = [
  "janus_client",
  "janus_core",
  "janus_server",
- "janus_test_util",
  "lazy_static",
  "prio",
  "rand",
diff --git a/Cargo.toml b/Cargo.toml
index 3156e6847..2a9e9255f 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,2 +1,3 @@
 [workspace]
-members = ["janus_core", "janus_client", "janus_server", "monolithic_integration_test", "test_util"]
+members = ["janus_core", "janus_client", "janus_server", "monolithic_integration_test"]
+resolver = "2"
diff --git a/Dockerfile b/Dockerfile
index 1af199492..e808c7262 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -9,7 +9,6 @@ COPY janus_core /src/janus_core
 COPY janus_client /src/janus_client
 COPY janus_server /src/janus_server
 COPY monolithic_integration_test /src/monolithic_integration_test
-COPY test_util /src/test_util
 COPY db/schema.sql /src/db/schema.sql
 RUN --mount=type=cache,target=/usr/local/cargo/registry --mount=type=cache,target=/src/target cargo build --release --bin $BINARY --features=prometheus && cp /src/target/release/$BINARY /$BINARY
 
diff --git a/janus_client/Cargo.toml b/janus_client/Cargo.toml
index 1d3fb8e3c..e37716cbd 100644
--- a/janus_client/Cargo.toml
+++ b/janus_client/Cargo.toml
@@ -22,7 +22,6 @@ 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"
 tracing-subscriber = { version = "0.3", features = ["std", "env-filter", "fmt"] }
diff --git a/janus_client/src/lib.rs b/janus_client/src/lib.rs
index 60353b182..d7b08221c 100644
--- a/janus_client/src/lib.rs
+++ b/janus_client/src/lib.rs
@@ -206,8 +206,11 @@ where
 mod tests {
     use super::*;
     use assert_matches::assert_matches;
-    use janus_core::{hpke::test_util::generate_hpke_config_and_private_key, message::TaskId};
-    use janus_test_util::{install_test_trace_subscriber, MockClock};
+    use janus_core::{
+        hpke::test_util::generate_hpke_config_and_private_key,
+        message::TaskId,
+        test_util::{install_test_trace_subscriber, MockClock},
+    };
     use mockito::mock;
     use prio::vdaf::prio3::Prio3;
     use url::Url;
diff --git a/janus_core/Cargo.toml b/janus_core/Cargo.toml
index fd3c2a508..9c72d140f 100644
--- a/janus_core/Cargo.toml
+++ b/janus_core/Cargo.toml
@@ -11,7 +11,7 @@ rust-version = "1.58"
 
 [features]
 database = ["bytes", "postgres-protocol", "postgres-types"]
-test-util = []
+test-util = ["assert_matches", "serde_json", "futures", "tracing", "tracing-log", "tracing-subscriber", "tokio/macros", "tokio/sync"]
 
 [dependencies]
 anyhow = "1"
@@ -30,6 +30,10 @@ serde = { version = "1.0.138", features = ["derive"] }
 thiserror = "1.0"
 tokio = { version = "^1.19", features = ["rt"] }
 
-[dev-dependencies]
-assert_matches = "1"
-serde_json = "1.0.82"
+# Dependencies required only if feature "test-util" is enabled
+assert_matches = { version = "1", optional = true }
+serde_json = { version = "1.0.82", optional = true }
+futures = { version = "0.3.21", optional = true }
+tracing = { version = "0.1.34", optional = true }
+tracing-log = { version = "0.1.3", optional = true }
+tracing-subscriber = { version = "0.3", features = ["std", "env-filter", "fmt"], optional = true }
diff --git a/janus_core/src/lib.rs b/janus_core/src/lib.rs
index c4b38ea0d..eb754e9c5 100644
--- a/janus_core/src/lib.rs
+++ b/janus_core/src/lib.rs
@@ -4,6 +4,8 @@ use tokio::task::JoinHandle;
 pub mod hpke;
 pub mod message;
 pub mod task;
+#[cfg(feature = "test-util")]
+pub mod test_util;
 pub mod time;
 
 /// This trait provides a mockable facade for [`tokio::task::spawn`].
diff --git a/test_util/src/dummy_vdaf.rs b/janus_core/src/test_util/dummy_vdaf.rs
similarity index 100%
rename from test_util/src/dummy_vdaf.rs
rename to janus_core/src/test_util/dummy_vdaf.rs
diff --git a/test_util/src/lib.rs b/janus_core/src/test_util/mod.rs
similarity index 98%
rename from test_util/src/lib.rs
rename to janus_core/src/test_util/mod.rs
index f456f0a42..b23d15ca9 100644
--- a/test_util/src/lib.rs
+++ b/janus_core/src/test_util/mod.rs
@@ -1,8 +1,8 @@
-use assert_matches::assert_matches;
-use janus_core::{
+use crate::{
     message::{Duration, Nonce, Time},
     time::Clock,
 };
+use assert_matches::assert_matches;
 use prio::{
     codec::Encode,
     vdaf::{self, PrepareTransition, VdafError},
@@ -17,7 +17,7 @@ pub mod dummy_vdaf;
 pub mod runtime;
 
 /// The Janus database schema.
-pub static SCHEMA: &str = include_str!("../../db/schema.sql");
+pub static SCHEMA: &str = include_str!("../../../db/schema.sql");
 
 /// This macro injects definitions of `DbHandle` and `ephemeral_datastore()`, for use in tests.
 /// It should be invoked once per binary target, and then `ephemeral_datastore()` can be called
@@ -168,7 +168,7 @@ macro_rules! define_ephemeral_datastore {
             ::tracing::trace!("Postgres container is up with URL {}", connection_string);
 
             // Create a random (ephemeral) key.
-            let datastore_key_bytes = ::janus_test_util::generate_aead_key_bytes();
+            let datastore_key_bytes = ::janus_core::test_util::generate_aead_key_bytes();
 
             DbHandle{
                 _db_container: db_container,
diff --git a/test_util/src/runtime.rs b/janus_core/src/test_util/runtime.rs
similarity index 99%
rename from test_util/src/runtime.rs
rename to janus_core/src/test_util/runtime.rs
index 7023ad8e7..566371104 100644
--- a/test_util/src/runtime.rs
+++ b/janus_core/src/test_util/runtime.rs
@@ -1,5 +1,5 @@
+use crate::Runtime;
 use futures::FutureExt;
-use janus_core::Runtime;
 use std::{
     collections::HashMap,
     future::Future,
diff --git a/janus_server/Cargo.toml b/janus_server/Cargo.toml
index 5ee19cfc5..273bfd200 100644
--- a/janus_server/Cargo.toml
+++ b/janus_server/Cargo.toml
@@ -11,7 +11,11 @@ tokio-console = ["console-subscriber"]
 jaeger = ["tracing-opentelemetry", "opentelemetry-jaeger"]
 otlp = ["tracing-opentelemetry", "opentelemetry-otlp", "opentelemetry-semantic-conventions", "tonic"]
 prometheus = ["opentelemetry-prometheus", "dep:prometheus"]
+<<<<<<< HEAD
 test-util = ["dep:janus_test_util", "dep:lazy_static", "dep:testcontainers"]
+=======
+test-util = ["janus_core/test-util", "lazy_static", "testcontainers"]
+>>>>>>> 8a0ce54 (Move `test_util` crate to `janus_core`)
 
 [dependencies]
 anyhow = "1"
@@ -62,6 +66,10 @@ url = { version = "2.2.2", features = ["serde"] }
 uuid = { version = "1.1.2", features = ["v4"] }
 warp = { version = "^0.3", features = ["tls"] }
 
+# Optional dependencies enabled by feature "test-util"
+lazy_static = { version = "1", optional = true }
+testcontainers = { version = "0.14.0", optional = true }
+
 [dev-dependencies]
 assert_matches = "1"
 hex = { version = "0.4.3", features = ["serde"] }
diff --git a/janus_server/src/aggregator.rs b/janus_server/src/aggregator.rs
index eafe58cf2..f51ebdfc1 100644
--- a/janus_server/src/aggregator.rs
+++ b/janus_server/src/aggregator.rs
@@ -70,7 +70,7 @@ use warp::{
 };
 
 #[cfg(test)]
-use janus_test_util::dummy_vdaf;
+use janus_core::test_util::dummy_vdaf;
 #[cfg(test)]
 use prio::vdaf::VdafError;
 
@@ -2091,8 +2091,8 @@ mod tests {
             HpkePrivateKey, Label,
         },
         message::{Duration, HpkeCiphertext, HpkeConfig, TaskId, Time},
+        test_util::{dummy_vdaf, install_test_trace_subscriber, run_vdaf, MockClock},
     };
-    use janus_test_util::{dummy_vdaf, install_test_trace_subscriber, run_vdaf, MockClock};
     use prio::{
         codec::Decode,
         field::Field64,
diff --git a/janus_server/src/aggregator/aggregate_share.rs b/janus_server/src/aggregator/aggregate_share.rs
index e89cea0b2..d1a69eaaa 100644
--- a/janus_server/src/aggregator/aggregate_share.rs
+++ b/janus_server/src/aggregator/aggregate_share.rs
@@ -85,7 +85,7 @@ impl CollectJobDriver {
 
             #[cfg(test)]
             VdafInstance::Fake => {
-                type FakeVdaf = janus_test_util::dummy_vdaf::VdafWithAggregationParameter<u8>;
+                type FakeVdaf = janus_core::test_util::dummy_vdaf::VdafWithAggregationParameter<u8>;
                 const VERIFY_KEY_LENGTH: usize = FakeVdaf::VERIFY_KEY_LENGTH;
                 self.step_collect_job_generic::<VERIFY_KEY_LENGTH, C, FakeVdaf>(
                     datastore,
@@ -438,14 +438,14 @@ mod tests {
     use assert_matches::assert_matches;
     use janus_core::{
         message::{Duration, HpkeCiphertext, HpkeConfigId, Interval, Nonce, Report, Role, TaskId},
+        test_util::{
+            dummy_vdaf::{AggregateShare, OutputShare, VdafWithAggregationParameter},
+            install_test_trace_subscriber,
+            runtime::TestRuntimeManager,
+            MockClock,
+        },
         Runtime,
     };
-    use janus_test_util::{
-        dummy_vdaf::{AggregateShare, OutputShare, VdafWithAggregationParameter},
-        install_test_trace_subscriber,
-        runtime::TestRuntimeManager,
-        MockClock,
-    };
     use mockito::mock;
     use std::str;
     use url::Url;
diff --git a/janus_server/src/aggregator/aggregation_job_creator.rs b/janus_server/src/aggregator/aggregation_job_creator.rs
index ef26c32a1..ad0b234a1 100644
--- a/janus_server/src/aggregator/aggregation_job_creator.rs
+++ b/janus_server/src/aggregator/aggregation_job_creator.rs
@@ -35,7 +35,10 @@ pub trait VdafHasAggregationParameter: private::Sealed {}
 impl<I, P, const L: usize> VdafHasAggregationParameter for prio::vdaf::poplar1::Poplar1<I, P, L> {}
 
 #[cfg(test)]
-impl VdafHasAggregationParameter for janus_test_util::dummy_vdaf::VdafWithAggregationParameter<u8> {}
+impl VdafHasAggregationParameter
+    for janus_core::test_util::dummy_vdaf::VdafWithAggregationParameter<u8>
+{
+}
 
 mod private {
     pub trait Sealed {}
@@ -43,7 +46,7 @@ mod private {
     impl<I, P, const L: usize> Sealed for prio::vdaf::poplar1::Poplar1<I, P, L> {}
 
     #[cfg(test)]
-    impl Sealed for janus_test_util::dummy_vdaf::VdafWithAggregationParameter<u8> {}
+    impl Sealed for janus_core::test_util::dummy_vdaf::VdafWithAggregationParameter<u8> {}
 }
 
 pub struct AggregationJobCreator<C: Clock> {
@@ -409,11 +412,11 @@ mod tests {
     use janus_core::{
         message::{Interval, Nonce, Report, Role, TaskId, Time},
         task::VdafInstance,
+        test_util::{
+            dummy_vdaf::VdafWithAggregationParameter, install_test_trace_subscriber, MockClock,
+        },
         time::Clock,
     };
-    use janus_test_util::{
-        dummy_vdaf::VdafWithAggregationParameter, install_test_trace_subscriber, MockClock,
-    };
     use prio::{
         codec::ParameterizedDecode,
         vdaf::{
diff --git a/janus_server/src/aggregator/aggregation_job_driver.rs b/janus_server/src/aggregator/aggregation_job_driver.rs
index 1927c1f7e..4adc7f96b 100644
--- a/janus_server/src/aggregator/aggregation_job_driver.rs
+++ b/janus_server/src/aggregator/aggregation_job_driver.rs
@@ -803,11 +803,11 @@ mod tests {
         },
         message::{Duration, HpkeConfig, Interval, Nonce, NonceChecksum, Report, Role, TaskId},
         task::VdafInstance,
+        test_util::{
+            install_test_trace_subscriber, run_vdaf, runtime::TestRuntimeManager, MockClock,
+        },
         Runtime,
     };
-    use janus_test_util::{
-        install_test_trace_subscriber, run_vdaf, runtime::TestRuntimeManager, MockClock,
-    };
     use mockito::mock;
     use prio::{
         codec::Encode,
diff --git a/janus_server/src/binary_utils/job_driver.rs b/janus_server/src/binary_utils/job_driver.rs
index 604acde4f..93fb7e651 100644
--- a/janus_server/src/binary_utils/job_driver.rs
+++ b/janus_server/src/binary_utils/job_driver.rs
@@ -200,8 +200,10 @@ where
 mod tests {
     use super::*;
     use crate::{message::AggregationJobId, task::VdafInstance};
-    use janus_core::message::TaskId;
-    use janus_test_util::{install_test_trace_subscriber, runtime::TestRuntimeManager, MockClock};
+    use janus_core::{
+        message::TaskId,
+        test_util::{install_test_trace_subscriber, runtime::TestRuntimeManager, MockClock},
+    };
     use tokio::sync::Mutex;
 
     #[tokio::test]
diff --git a/janus_server/src/datastore.rs b/janus_server/src/datastore.rs
index abd8f18d2..4bc9945c2 100644
--- a/janus_server/src/datastore.rs
+++ b/janus_server/src/datastore.rs
@@ -2918,7 +2918,7 @@ pub mod test_util {
     use super::{Crypter, Datastore};
     use janus_core::time::Clock;
 
-    janus_test_util::define_ephemeral_datastore!();
+    janus_core::define_ephemeral_datastore!();
 }
 
 #[cfg(test)]
@@ -2938,10 +2938,10 @@ mod tests {
     use janus_core::{
         hpke::{self, associated_data_for_aggregate_share, HpkeApplicationInfo, Label},
         message::{Duration, ExtensionType, HpkeConfigId, Interval, Role, Time},
-    };
-    use janus_test_util::{
-        dummy_vdaf::{self, VdafWithAggregationParameter},
-        generate_aead_key, install_test_trace_subscriber, MockClock,
+        test_util::{
+            dummy_vdaf::{self, VdafWithAggregationParameter},
+            generate_aead_key, install_test_trace_subscriber, MockClock,
+        },
     };
     use prio::{
         field::{Field128, Field64},
diff --git a/janus_server/tests/server_shutdown.rs b/janus_server/tests/server_shutdown.rs
index 473509b67..d31dcc868 100644
--- a/janus_server/tests/server_shutdown.rs
+++ b/janus_server/tests/server_shutdown.rs
@@ -22,7 +22,7 @@ use std::{
 };
 use wait_timeout::ChildExt;
 
-janus_test_util::define_ephemeral_datastore!();
+janus_core::define_ephemeral_datastore!();
 
 /// Try to find an open port by binding to an ephemeral port, saving the port
 /// number, and closing the listening socket. This may still fail due to race
diff --git a/monolithic_integration_test/Cargo.toml b/monolithic_integration_test/Cargo.toml
index dc757febd..21e44c712 100644
--- a/monolithic_integration_test/Cargo.toml
+++ b/monolithic_integration_test/Cargo.toml
@@ -10,7 +10,7 @@ publish = false
 chrono = "0.4.19"
 deadpool-postgres = "0.10.1"
 futures = "0.3.21"
-janus_core = { path = "../janus_core" }
+janus_core = { path = "../janus_core", features = ["test-util"] }
 janus_client = { path = "../janus_client" }
 janus_server = { path = "../janus_server", features = ["test-util"] }
 lazy_static = "1"
@@ -19,7 +19,6 @@ rand = "0.8"
 reqwest = { version = "0.11.11", default-features = false, features = ["rustls-tls"] }
 ring = "0.16.20"
 testcontainers = "0.14.0"
-janus_test_util = { path = "../test_util" }
 tokio = { version = "^1.19", features = ["full", "tracing"] }
 tokio-postgres = { version = "0.7.6", features = ["with-chrono-0_4"] }
 tracing = "0.1.34"
diff --git a/monolithic_integration_test/tests/integration_test.rs b/monolithic_integration_test/tests/integration_test.rs
index 34ab20a67..9cd5cda94 100644
--- a/monolithic_integration_test/tests/integration_test.rs
+++ b/monolithic_integration_test/tests/integration_test.rs
@@ -6,6 +6,7 @@ use janus_core::{
     },
     message::{Duration, HpkeConfig, Interval, Role, TaskId},
     task::VdafInstance,
+    test_util::install_test_trace_subscriber,
     time::{Clock, RealClock},
     TokioRuntime,
 };
@@ -19,7 +20,6 @@ use janus_server::{
     message::{CollectReq, CollectResp},
     task::{test_util::generate_aggregator_auth_token, Task, PRIO3_AES128_VERIFY_KEY_LENGTH},
 };
-use janus_test_util::install_test_trace_subscriber;
 use prio::{
     codec::{Decode, Encode},
     field::Field64,
@@ -46,7 +46,7 @@ use tokio::{
 };
 use url::Url;
 
-janus_test_util::define_ephemeral_datastore!();
+janus_core::define_ephemeral_datastore!();
 
 #[tokio::test(flavor = "multi_thread")]
 async fn end_to_end() {
diff --git a/test_util/Cargo.toml b/test_util/Cargo.toml
deleted file mode 100644
index 207899424..000000000
--- a/test_util/Cargo.toml
+++ /dev/null
@@ -1,23 +0,0 @@
-[package]
-name = "janus_test_util"
-version = "0.1.0"
-edition = "2021"
-license = "MPL-2.0"
-rust-version = "1.58"
-publish = false
-
-[dependencies]
-assert_matches = "1"
-chrono = "0.4"
-futures = "0.3.21"
-janus_core = { path = "../janus_core" }
-prio = "0.8.0"
-rand = "0.8"
-ring = "0.16.20"
-tracing = "0.1.34"
-tracing-log = "0.1.3"
-tracing-subscriber = { version = "0.3", features = ["std", "env-filter", "fmt"] }
-tokio = { version = "^1.19", features = ["rt", "sync"] }
-
-[dev-dependencies]
-tokio = { version = "*", features = ["macros"] }