Avoid building inside the source dir in autopkgtest

autopkgtest says:
Tests may not modify the source tree (and may not have write access to it).

We don't really modify the source of course, but we created our build/
directory in the tree, which seems to work just fine (for now), but lets
be nice.

1 files changed, 19 insertions, 8 deletions

diff --git a/debian/tests/run-tests b/debian/tests/run-tests
index ff3359fae..461042641 100644
--- a/debian/tests/run-tests
+++ b/debian/tests/run-tests
@@ -1,19 +1,30 @@
 #!/bin/sh
-
 set -e
 
-if [ ! -e build/CMakeCache.txt ]; then
-    mkdir build || true
-    ( cd build && cmake .. )
+SOURCE_DIR="$(pwd)"
+if [ -z "$AUTOPKGTEST_TMP" ]; then
+   BUILD_DIR=''
+   cleanup() {
+      if [ -n "$BUILD_DIR" ]; then cd /; rm -rf -- "$BUILD_DIR"; fi
+      BUILD_DIR=''
+   }
+   trap 'cleanup' 0 HUP INT QUIT ILL ABRT FPE SEGV PIPE TERM
+   BUILD_DIR="$(mktemp -d)"
+else
+   BUILD_DIR="$AUTOPKGTEST_TMP"
+fi
+
+if [ ! -e "${BUILD_DIR}/CMakeCache.txt" ]; then
+   cmake -S "$SOURCE_DIR" -B "$BUILD_DIR"
 fi
 
-make -C build/test/interactive-helper
+make -C "${BUILD_DIR}/test/interactive-helper"
 
 # run tests against the installed apt, use "env -i" to ensure
 # the host env does not pollute our environment
 env -i \
-APT_INTEGRATION_TESTS_SOURCE_DIR=$(pwd) \
-APT_INTEGRATION_TESTS_HELPERS_BIN_DIR=$(pwd)/build/test/interactive-helper \
+APT_INTEGRATION_TESTS_SOURCE_DIR="${SOURCE_DIR}" \
+APT_INTEGRATION_TESTS_HELPERS_BIN_DIR="${BUILD_DIR}/test/interactive-helper" \
 APT_INTEGRATION_TESTS_METHODS_DIR=/usr/lib/apt/methods \
 APT_INTEGRATION_TESTS_LIBEXEC_DIR=/usr/lib/apt/ \
 APT_INTEGRATION_TESTS_INTERNAL_SOLVER=/usr/lib/apt/solvers/apt \
@@ -23,4 +34,4 @@ APT_INTEGRATION_TESTS_BUILD_DIR=/usr/bin \
 APT_INTEGRATION_TESTS_FTPARCHIVE_BIN_DIR=/usr/bin \
 APT_INTEGRATION_TESTS_LIBRARY_PATH=/dev/null/does/not/exist \
 APT_INTEGRATION_TESTS_ARTIFACTS_DIR="${AUTOPKGTEST_ARTIFACTS}" \
-./test/integration/run-tests -q
+"${SOURCE_DIR}/test/integration/run-tests" -q