diff --git a/contrib/_test.sh b/contrib/_test.sh
index 38c73159d..c2f057ef2 100755
--- a/contrib/_test.sh
+++ b/contrib/_test.sh
@@ -29,50 +29,50 @@ cargo test -- --ignored --exact 'tests::test_panic_raw_ctx_should_terminate_abno
 export CARGO_TERM_VERBOSE=true
 
 # Defaults / sanity checks
-cargo build --all
-cargo test --all
+cargo build --locked --all
+cargo test --locked --all
 
 if [ "$DO_FEATURE_MATRIX" = true ]; then
-    cargo build --all --no-default-features
-    cargo test --all --no-default-features
+    cargo build --locked --all --no-default-features
+    cargo test --locked --all --no-default-features
 
     # All features
-    cargo build --all --no-default-features --features="$FEATURES"
-    cargo test --all --no-default-features --features="$FEATURES"
+    cargo build --locked --all --no-default-features --features="$FEATURES"
+    cargo test --locked --all --no-default-features --features="$FEATURES"
     # Single features
     for feature in ${FEATURES}
     do
-        cargo build --all --no-default-features --features="$feature"
-        cargo test --all --no-default-features --features="$feature"
+        cargo build --locked --all --no-default-features --features="$feature"
+        cargo test --locked --all --no-default-features --features="$feature"
     done
     # Features tested with 'std' feature enabled.
     for feature in ${FEATURES}
     do
-        cargo build --all --no-default-features --features="std,$feature"
-        cargo test --all --no-default-features --features="std,$feature"
+        cargo build --locked --all --no-default-features --features="std,$feature"
+        cargo test --locked --all --no-default-features --features="std,$feature"
     done
     # Other combos
-    RUSTFLAGS='--cfg=secp256k1_fuzz' RUSTDOCFLAGS='--cfg=secp256k1_fuzz' cargo test --all
-    RUSTFLAGS='--cfg=secp256k1_fuzz' RUSTDOCFLAGS='--cfg=secp256k1_fuzz' cargo test --all --features="$FEATURES"
-    cargo test --all --features="rand serde"
+    RUSTFLAGS='--cfg=secp256k1_fuzz' RUSTDOCFLAGS='--cfg=secp256k1_fuzz' cargo test --locked --all
+    RUSTFLAGS='--cfg=secp256k1_fuzz' RUSTDOCFLAGS='--cfg=secp256k1_fuzz' cargo test --locked --all --features="$FEATURES"
+    cargo test --locked --all --features="rand serde"
 
     if [ "$NIGHTLY" = true ]; then
-        cargo test --all --all-features
-        RUSTFLAGS='--cfg=secp256k1_fuzz' RUSTDOCFLAGS='--cfg=secp256k1_fuzz' cargo test --all --all-features
+        cargo test --locked --all --all-features
+        RUSTFLAGS='--cfg=secp256k1_fuzz' RUSTDOCFLAGS='--cfg=secp256k1_fuzz' cargo test --locked --all --all-features
     fi
 
     # Examples
-    cargo run --example sign_verify --features=bitcoin-hashes-std
-    cargo run --example sign_verify_recovery --features=recovery,bitcoin-hashes-std
-    cargo run --example generate_keys --features=rand-std
+    cargo run --locked --example sign_verify --features=bitcoin-hashes-std
+    cargo run --locked --example sign_verify_recovery --features=recovery,bitcoin-hashes-std
+    cargo run --locked --example generate_keys --features=rand-std
 fi
 
 if [ "$DO_LINT" = true ]
 then
-    cargo clippy --all-features --all-targets -- -D warnings
-    cargo clippy --example sign_verify --features=bitcoin-hashes-std -- -D warnings
-    cargo clippy --example sign_verify_recovery --features=recovery,bitcoin-hashes-std -- -D warnings
-    cargo clippy --example generate_keys --features=rand-std -- -D warnings
+    cargo clippy --locked --all-features --all-targets -- -D warnings
+    cargo clippy --locked --example sign_verify --features=bitcoin-hashes-std -- -D warnings
+    cargo clippy --locked --example sign_verify_recovery --features=recovery,bitcoin-hashes-std -- -D warnings
+    cargo clippy --locked --example generate_keys --features=rand-std -- -D warnings
 fi
 
 # Build the docs if told to (this only works with the nightly toolchain)
diff --git a/contrib/test.sh b/contrib/test.sh
index cd742e28e..46872fe72 100755
--- a/contrib/test.sh
+++ b/contrib/test.sh
@@ -3,6 +3,7 @@
 set -ex
 
 REPO_DIR=$(git rev-parse --show-toplevel)
+DEPS="recent minimal"
 
 # Webassembly stuff
 #
@@ -18,4 +19,22 @@ if [ "$DO_WASM" = true ]; then
     exit 0
 fi
 
-$REPO_DIR/contrib/_test.sh
+for dep in $DEPS
+do
+    "Cargo-$dep.lock" Cargo.lock
+    $REPO_DIR/contrib/_test.sh
+
+    if [ "$dep" = recent ];
+    then
+        # We always test committed dependencies but we want to warn if they could've been updated
+        cargo update
+        if diff Cargo-recent.lock Cargo.lock;
+        then
+            echo "Dependencies are up to date"
+        else
+            echo "::warning file=Cargo-recent.lock::Dependencies could be updated"
+        fi
+    fi
+done
+
+exit 0