CI: Use a separate script to run integration tests

In preparation for using the `run_task.sh` script from
`rust-bitcoin-maintainer-tools` pull the integration stuff out of
`test.sh` and into a separate script. Update the CI job to use the new
script.

Includes switch to the dtolnay runner (maintaining use of stable toolchain).

.github/workflows/rust.yml

@@ -31,12 +31,12 @@ jobs:
         env: ${{ matrix.env }}
         run: ./contrib/test.sh
 
-  integrations-tests:
-    name: Integration Tests
+  Integration:
+    name: Integration tests - stable toolchain
     runs-on: ubuntu-latest
     strategy:
+      fail-fast: false
       matrix:
-        rust: [stable]
         bitcoinversion:
           [
             "0.18.0",
@@ -48,15 +48,11 @@ jobs:
             "0.21.0",
           ]
     steps:
-      - name: Checkout Crate
-        uses: actions/checkout@v2
-      - name: Checkout Toolchain
-        uses: actions-rs/toolchain@v1
-        with:
-          profile: minimal
-          toolchain: ${{ matrix.rust }}
-          override: true
-      - name: Running test script
+      - name: "Checkout repo"
+        uses: actions/checkout@v4
+      - name: "Select toolchain"
+        uses: dtolnay/rust-toolchain@stable
+      - name: "Run integration tests"
         env:
           BITCOINVERSION: ${{ matrix.bitcoinversion }}
-        run: ./contrib/test.sh
+        run: ./contrib/integration_test.sh

contrib/integration_test.sh

@@ -0,0 +1,45 @@
+#!/usr/bin/env bash
+#
+# Run the integration test optionally downloading Bitcoin Core binary if BITCOINVERSION is set.
+
+set -euo pipefail
+
+REPO_DIR=$(git rev-parse --show-toplevel)
+
+# Make all cargo invocations verbose.
+export CARGO_TERM_VERBOSE=true
+
+main() {
+    # If a specific version of Bitcoin Core is set then download the binary.
+    if [ -n "${BITCOINVERSION+x}" ]; then
+        download_binary
+    fi
+
+    need_cmd bitcoind
+
+    cd integration_test
+    ./run.sh
+}
+
+download_binary() {
+    wget https://bitcoincore.org/bin/bitcoin-core-$BITCOINVERSION/bitcoin-$BITCOINVERSION-x86_64-linux-gnu.tar.gz
+    tar -xzvf bitcoin-$BITCOINVERSION-x86_64-linux-gnu.tar.gz
+    export PATH=$PATH:$(pwd)/bitcoin-$BITCOINVERSION/bin
+}
+
+err() {
+    echo "$1" >&2
+    exit 1
+}
+
+need_cmd() {
+    if ! command -v "$1" > /dev/null 2>&1
+    then err "need '$1' (command not found)"
+    fi
+}
+
+#
+# Main script
+#
+main "$@"
+exit 0