From 0a2c8e4864dc30b6d1ed86a16793d37699707650 Mon Sep 17 00:00:00 2001
From: Erik Arvstedt <erik.arvstedt@gmail.com>
Date: Sat, 6 Feb 2021 09:38:58 +0100
Subject: [PATCH] run-tests: add option --copy-src

---
 test/lib/copy-src.sh | 18 ++++++++++++++++++
 test/run-tests.sh    | 15 +++++++++++++++
 2 files changed, 33 insertions(+)
 create mode 100644 test/lib/copy-src.sh

diff --git a/test/lib/copy-src.sh b/test/lib/copy-src.sh
new file mode 100644
index 0000000..71bc3a2
--- /dev/null
+++ b/test/lib/copy-src.sh
@@ -0,0 +1,18 @@
+# Re-run run-tests.sh in a snapshot copy of the source.
+# Maintain /tmp/nix-bitcoin-src as a source cache to minimize copies.
+
+tmp=$(mktemp -d '/tmp/nix-bitcoin-src.XXXXX')
+
+# Ignore errors from now on
+set +e
+
+# Move source cache if it exists (atomic)
+mv /tmp/nix-bitcoin-src $tmp/src 2>/dev/null
+
+rsync -a --delete --exclude='.git*' "$scriptDir/../" $tmp/src && \
+  echo "Copied src" && \
+  _nixBitcoinInCopySrc=1 $tmp/src/test/run-tests.sh "${args[@]}"
+
+# Set the current src as the source cache (atomic)
+mv -T $tmp/src /tmp/nix-bitcoin-src 2>/dev/null
+rm -rf $tmp
diff --git a/test/run-tests.sh b/test/run-tests.sh
index e59cc56..3f30408 100755
--- a/test/run-tests.sh
+++ b/test/run-tests.sh
@@ -42,12 +42,20 @@
 #     For now, creating NixOS containers requires root permissions.
 #     See ./lib/make-container.sh for a complete documentation.
 #
+#   Run tests from a snapshot copy of the source files
+#   ./run-tests.sh --copy-src|-c ...
+#
+#     This allows you to continue editing the nix-bitcoin sources while tests are running
+#     and reading source files.
+#     Files are copied to /tmp, a caching scheme helps minimizing copies.
+#
 #   To add custom scenarios, set the environment variable `scenarioOverridesFile`.
 
 set -eo pipefail
 
 scriptDir=$(cd "${BASH_SOURCE[0]%/*}" && pwd)
 
+args=("$@")
 scenario=
 outLinkPrefix=
 ciBuild=
@@ -77,6 +85,13 @@ while :; do
             shift
             ciBuild=1
             ;;
+        --copy-src|-c)
+            shift
+            if [[ ! $_nixBitcoinInCopySrc ]]; then
+                . "$scriptDir/lib/copy-src.sh"
+                exit
+            fi
+            ;;
         *)
             break
     esac