Add tests for subreaper-less Tini

If we're going to make subreaper support an option, we should ensure
that running without subreaper support also works.

ci/run_build.sh

@@ -13,11 +13,18 @@ export SOURCE_DIR="$(readlink -f "${SOURCE_DIR}")"
 export DIST_DIR="$(readlink -f "${DIST_DIR}")"
 export BUILD_DIR="$(readlink -f "${BUILD_DIR}")"
 
+# Configuration
+: ${FORCE_SUBREAPER:="1"}
+export FORCE_SUBREAPER
+
 
 # Our build platform doesn't have those newer Linux flags, but we want Tini to have subreaper support
 # We also use those in our tests
-export CFLAGS="-DPR_SET_CHILD_SUBREAPER=36 -DPR_GET_CHILD_SUBREAPER=37"
-
+CFLAGS="-DPR_SET_CHILD_SUBREAPER=36 -DPR_GET_CHILD_SUBREAPER=37"
+if [[ "${FORCE_SUBREAPER}" -eq 1 ]]; then
+  # If FORCE_SUBREAPER is requested, then we set those CFLAGS for the Tini build
+  export CFLAGS
+fi
 
 # Ensure Python output is not buffered (to make tests output clearer)
 export PYTHONUNBUFFERED=1
@@ -69,6 +76,7 @@ virtualenv --system-site-packages "${VENV}"
 
 # Don't use activate because it does not play nice with nounset
 export PATH="${VENV}/bin:${PATH}"
+export CFLAGS  # We need them to build our test suite, regardless of FORCE_SUBREAPER
 
 # Install test dependencies
 pip install psutil python-prctl

ddist.sh

@@ -14,5 +14,10 @@ rm -f "${HERE}/dist"/*
 # Create the build image
 docker build -t "${IMG}" .
 
-# Run the build
-docker run --rm --volume="${HERE}:${SRC}" -e BUILD_DIR=/tmp/tini-build -e SOURCE_DIR="${SRC}" "${IMG}" "${SRC}/ci/run_build.sh"
+# Run test without subreaper support, don't copy build files here
+docker run --rm \
+  --volume="${HERE}:${SRC}" \
+  -e BUILD_DIR=/tmp/tini-build \
+  -e SOURCE_DIR="${SRC}" \
+  -e FORCE_SUBREAPER="${FORCE_SUBREAPER}" \
+  "${IMG}" "${SRC}/ci/run_build.sh"

run_tests.sh

@@ -0,0 +1,13 @@
+#!/bin/bash
+set -o errexit
+set -o nounset
+
+REL_HERE=$(dirname "${BASH_SOURCE}")
+HERE=$(cd "${REL_HERE}"; pwd)
+
+for i in $(seq 0 1); do
+  export FORCE_SUBREAPER="${i}"
+  echo "Testing with FORCE_SUBREAPER=${FORCE_SUBREAPER}"
+  "${HERE}/ddist.sh"
+  "${HERE}/dtest.sh"
+done

test/run_inner_tests.py

@@ -13,12 +13,17 @@ def main():
     proxy = os.path.join(src, "test", "subreaper-proxy.py")
     tini = os.path.join(build, "tini")
 
-    for target, env in [
-        ([proxy, tini, "--"], {}),
-        ([tini, "-s", "--"], {}),
-        ([tini, "--"], {"TINI_SUBREAPER": ""}),
-    ]:
+    subreaper_support = bool(int(os.environ["FORCE_SUBREAPER"]))
 
+    tests = [([proxy, tini, "--"], {}),]
+
+    if subreaper_support:
+        tests.extend([
+            ([tini, "-s", "--"], {}),
+            ([tini, "--"], {"TINI_SUBREAPER": ""}),
+            ])
+
+    for target, env in tests:
         # Run the reaping test
         print "Running reaping test ({0} with env {1})".format(" ".join(target), env)
         p = subprocess.Popen(target + [os.path.join(src, "test", "reaping", "stage_1.py")],
@@ -26,7 +31,11 @@ def main():
                              stdout=subprocess.PIPE, stderr=subprocess.PIPE)
 
         out, err = p.communicate()
-        assert "zombie reaping won't work" not in err, "Warning message was output!"
+
+        if subreaper_support:
+            # If subreaper support sin't available, Tini won't looku p its subreaper bit
+            # and will output the error message here.
+            assert "zombie reaping won't work" not in err, "Warning message was output!"
         ret = p.wait()
         assert ret == 0, "Reaping test failed!"