diff --git a/test/README.testsuite b/test/README.testsuite
index 1b4736013d..da989c1e0d 100644
--- a/test/README.testsuite
+++ b/test/README.testsuite
@@ -8,7 +8,7 @@ $ sudo test/run-integration-tests.sh
 ninja: Entering directory `/home/zbyszek/src/systemd/build'
 ninja: no work to do.
 --x-- Running TEST-01-BASIC --x--
-+ make -C TEST-01-BASIC BUILD_DIR=/home/zbyszek/src/systemd/build clean setup run
++ make -C TEST-01-BASIC clean setup run
 make: Entering directory '/home/zbyszek/src/systemd/test/TEST-01-BASIC'
 TEST-01-BASIC CLEANUP: Basic systemd setup
 TEST-01-BASIC SETUP: Basic systemd setup
@@ -17,7 +17,7 @@ TEST-01-BASIC RUN: Basic systemd setup [OK]
 make: Leaving directory '/home/zbyszek/src/systemd/test/TEST-01-BASIC'
 --x-- Result of TEST-01-BASIC: 0 --x--
 --x-- Running TEST-02-CRYPTSETUP --x--
-+ make -C TEST-02-CRYPTSETUP BUILD_DIR=/home/zbyszek/src/systemd/build clean setup run
++ make -C TEST-02-CRYPTSETUP clean setup run
 
 If one of the tests fails, then $subdir/test.log contains the log file of
 the test.
@@ -41,6 +41,14 @@ $ sudo make -C test/TEST-01-BASIC BUILD_DIR=../../some-other-build/ ...
 Note that in the second case, the path is relative to the test case directory.
 An absolute path may also be used in both cases.
 
+Testing installed binaries instead of built
+===========================================
+
+To run the extended testsuite using the systemd installed on the system instead
+of the systemd from a build, use the NO_BUILD=1:
+
+$ sudo NO_BUILD=1 test/run-integration-tests
+
 Configuration variables
 =======================
 
diff --git a/test/TEST-01-BASIC/Makefile b/test/TEST-01-BASIC/Makefile
index 79fe9688b8..9b90a1c2bc 100644
--- a/test/TEST-01-BASIC/Makefile
+++ b/test/TEST-01-BASIC/Makefile
@@ -1,6 +1,4 @@
-BUILD_DIR=$(shell ../../tools/find-build-dir.sh)
-
 all setup run clean clean-again:
-	@basedir=../.. TEST_BASE_DIR=../ BUILD_DIR=$(BUILD_DIR) ./test.sh --$@
+	@TEST_BASE_DIR=../ ./test.sh --$@
 
 .PHONY: all setup run clean clean-again
diff --git a/test/TEST-01-BASIC/test.sh b/test/TEST-01-BASIC/test.sh
index 606b0dbfaf..66c35fe2b7 100755
--- a/test/TEST-01-BASIC/test.sh
+++ b/test/TEST-01-BASIC/test.sh
@@ -9,8 +9,9 @@ TEST_REQUIRE_INSTALL_TESTS=0
 
 test_append_files() {
     # install tests manually so the test is functional even when -Dinstall-tests=false
-    mkdir -p $1/usr/lib/systemd/tests/testdata/units/
-    cp -v $(dirname $0)/../units/{testsuite-01,end}.service $1/usr/lib/systemd/tests/testdata/units/
+    local dst="$1/usr/lib/systemd/tests/testdata/units/"
+    mkdir -p "$dst"
+    cp -v $TEST_UNITS_DIR/{testsuite-01,end}.service $TEST_UNITS_DIR/testsuite.target "$dst"
 }
 
 do_test "$@" 01
diff --git a/test/TEST-52-HONORFIRSTSHUTDOWN/Makefile b/test/TEST-52-HONORFIRSTSHUTDOWN/Makefile
index a06599081b..71487d7076 100644
--- a/test/TEST-52-HONORFIRSTSHUTDOWN/Makefile
+++ b/test/TEST-52-HONORFIRSTSHUTDOWN/Makefile
@@ -1,7 +1,5 @@
-BUILD_DIR=$(shell ../../tools/find-build-dir.sh)
-
 all setup run clean clean-again:
-	@basedir=../.. TEST_BASE_DIR=../ BUILD_DIR=$(BUILD_DIR) ./test.sh --$@
+	@TEST_BASE_DIR=../ ./test.sh --$@
 
 # finish option is used to run checks that can only be run outside of
 # the test execution. Example case, honor first shutdown, proof is obtained
@@ -11,6 +9,6 @@ all setup run clean clean-again:
 # the test will loop and will be terminated via a command timeout.
 # This just provides concrete confirmation.
 finish:
-	@basedir=../.. TEST_BASE_DIR=../ BUILD_DIR=$(BUILD_DIR) ./fini.sh --$@
+	@TEST_BASE_DIR=../ ./fini.sh --$@
 
 .PHONY: all setup run clean clean-again finish
diff --git a/test/run-integration-tests.sh b/test/run-integration-tests.sh
index e9307601ff..036c075eef 100755
--- a/test/run-integration-tests.sh
+++ b/test/run-integration-tests.sh
@@ -1,14 +1,46 @@
 #!/usr/bin/env bash
 set -e
 
-BUILD_DIR="$($(dirname "$0")/../tools/find-build-dir.sh)"
+if [ "$NO_BUILD" ]; then
+    BUILD_DIR=""
+elif BUILD_DIR="$($(dirname "$0")/../tools/find-build-dir.sh)"; then
+    ninja -C "$BUILD_DIR"
+else
+    echo "No build found, please set BUILD_DIR or NO_BUILD" >&2
+    exit 1
+fi
+
 if [ $# -gt 0 ]; then
-    args="$@"
+    args="$*"
 else
     args="setup run clean-again"
 fi
-args_no_clean=$(sed -r 's/\bclean.*\b//g' <<<$args)
-do_clean=$( [ "$args" = "$args_no_clean" ]; echo $? )
+
+VALID_TARGETS="all setup run clean clean-again"
+
+is_valid_target() {
+    for target in $VALID_TARGETS; do
+        [ "$1" = "$target" ] && return 0
+    done
+    return 1
+}
+
+# reject invalid make targets in $args
+for arg in $args; do
+    if ! is_valid_target "$arg"; then
+        echo "Invalid target: $arg" >&2
+        exit 1
+    fi
+done
+
+CLEAN=0
+CLEANAGAIN=0
+
+# separate 'clean' and 'clean-again' operations
+[[ "$args" =~ "clean-again" ]] && CLEANAGAIN=1
+args=${args/clean-again}
+[[ "$args" =~ "clean" ]] && CLEAN=1
+args=${args/clean}
 
 declare -A results
 declare -A times
@@ -18,16 +50,6 @@ FAILURES=0
 
 cd "$(dirname "$0")"
 
-# Let's always do the cleaning operation first, because it destroys the image
-# cache.
-if [ $do_clean = 1 ]; then
-    for TEST in TEST-??-* ; do
-        ( set -x ; make -C "$TEST" "BUILD_DIR=$BUILD_DIR" clean )
-    done
-
-    [ -n "$args_no_clean" ] || exit 0
-fi
-
 pass_deny_list() {
     for marker in $DENY_LIST_MARKERS $BLACKLIST_MARKERS; do
         if [ -f "$1/$marker" ]; then
@@ -38,28 +60,40 @@ pass_deny_list() {
     return 0
 }
 
-for TEST in TEST-??-* ; do
-    COUNT=$(($COUNT+1))
+# Let's always do the cleaning operation first, because it destroys the image
+# cache.
+if [ $CLEAN = 1 ]; then
+    for TEST in TEST-??-* ; do
+        ( set -x ; make -C "$TEST" clean )
+    done
+fi
 
-    pass_deny_list $TEST || continue
-    start=$(date +%s)
+# Run actual tests (if requested)
+if [[ $args =~ [a-z] ]]; then
+    for TEST in TEST-??-* ; do
+        COUNT=$(($COUNT+1))
 
-    echo -e "\n--x-- Running $TEST --x--"
-    set +e
-    ( set -x ; make -C "$TEST" "BUILD_DIR=$BUILD_DIR" $args_no_clean )
-    RESULT=$?
-    set -e
-    echo "--x-- Result of $TEST: $RESULT --x--"
+        pass_deny_list $TEST || continue
+        start=$(date +%s)
 
-    results["$TEST"]="$RESULT"
-    times["$TEST"]=$(( $(date +%s) - $start ))
+        echo -e "\n--x-- Running $TEST --x--"
+        set +e
+        ( set -x ; make -C "$TEST" $args )
+        RESULT=$?
+        set -e
+        echo "--x-- Result of $TEST: $RESULT --x--"
 
-    [ "$RESULT" -ne "0" ] && FAILURES=$(($FAILURES+1))
-done
+        results["$TEST"]="$RESULT"
+        times["$TEST"]=$(( $(date +%s) - $start ))
 
-if [ $FAILURES -eq 0 -a $do_clean = 1 ]; then
+        [ "$RESULT" -ne "0" ] && FAILURES=$(($FAILURES+1))
+    done
+fi
+
+# Run clean-again, if requested, and if no tests failed
+if [ $FAILURES -eq 0 -a $CLEANAGAIN = 1 ]; then
     for TEST in ${!results[@]}; do
-        ( set -x ; make -C "$TEST" "BUILD_DIR=$BUILD_DIR" clean-again )
+        ( set -x ; make -C "$TEST" clean-again )
     done
 fi
 
diff --git a/test/test-functions b/test/test-functions
index 837082890a..a9341445d5 100644
--- a/test/test-functions
+++ b/test/test-functions
@@ -43,6 +43,22 @@ if ! ROOTLIBDIR=$(pkg-config --variable=systemdutildir systemd); then
     ROOTLIBDIR=/usr/lib/systemd
 fi
 
+# The calling test.sh scripts have TEST_BASE_DIR set via their Makefile, but we don't need them to provide it
+TEST_BASE_DIR=${TEST_BASE_DIR:-$(realpath $(dirname "$BASH_SOURCE"))}
+TEST_UNITS_DIR="$TEST_BASE_DIR/units"
+SOURCE_DIR=$(realpath "$TEST_BASE_DIR/..")
+TOOLS_DIR="$SOURCE_DIR/tools"
+
+# note that find-build-dir.sh will return $BUILD_DIR if provided, else it will try to find it
+if ! BUILD_DIR=$($TOOLS_DIR/find-build-dir.sh); then
+    if [ "$NO_BUILD" ]; then
+        BUILD_DIR=$SOURCE_DIR
+    else
+        echo "ERROR: no build found, please set BUILD_DIR or use NO_BUILD" >&2
+        exit 1
+    fi
+fi
+
 PATH_TO_INIT=$ROOTLIBDIR/systemd
 [ "$SYSTEMD_JOURNALD" ] || SYSTEMD_JOURNALD=$(which -a $BUILD_DIR/systemd-journald $ROOTLIBDIR/systemd-journald 2>/dev/null | grep '^/' -m1)
 [ "$SYSTEMD_JOURNAL_REMOTE" ] || SYSTEMD_JOURNAL_REMOTE=$(which -a $BUILD_DIR/systemd-journal-remote $ROOTLIBDIR/systemd-journal-remote 2>/dev/null | grep '^/' -m1)
@@ -50,6 +66,17 @@ PATH_TO_INIT=$ROOTLIBDIR/systemd
 [ "$SYSTEMD_NSPAWN" ] || SYSTEMD_NSPAWN=$(which -a $BUILD_DIR/systemd-nspawn systemd-nspawn 2>/dev/null | grep '^/' -m1)
 [ "$JOURNALCTL" ] || JOURNALCTL=$(which -a $BUILD_DIR/journalctl journalctl 2>/dev/null | grep '^/' -m1)
 
+TESTFILE=${BASH_SOURCE[1]}
+if [ -z "$TESTFILE" ]; then
+    echo "ERROR: test-functions must be sourced from one of the TEST-*/test.sh scripts" >&2
+    exit 1
+fi
+TESTNAME=$(basename $(dirname $(realpath $TESTFILE)))
+STATEDIR="$BUILD_DIR/test/$TESTNAME"
+STATEFILE="$STATEDIR/.testdir"
+IMAGESTATEDIR="$STATEDIR/.."
+TESTLOG="$STATEDIR/test.log"
+
 BASICTOOLS=(
     awk
     basename
@@ -148,11 +175,6 @@ DEBUGTOOLS=(
     vi
 )
 
-STATEDIR="${BUILD_DIR:-.}/test/$(basename $(dirname $(realpath $0)))"
-STATEFILE="$STATEDIR/.testdir"
-IMAGESTATEDIR="$STATEDIR/.."
-TESTLOG="$STATEDIR/test.log"
-
 is_built_with_asan() {
     if ! type -P objdump >/dev/null; then
         ddebug "Failed to find objdump. Assuming systemd hasn't been built with ASAN."
@@ -663,7 +685,7 @@ install_dmevent() {
     fi
 }
 
-install_systemd() {
+install_compiled_systemd() {
     ddebug "Install compiled systemd"
 
     local _ninja_bin=$(type -P ninja || type -P ninja-build)
@@ -672,6 +694,42 @@ install_systemd() {
         exit 1
     fi
     (set -x; DESTDIR=$initdir "$_ninja_bin" -C $BUILD_DIR install)
+}
+
+install_debian_systemd() {
+    ddebug "Install debian systemd"
+
+    local _systemd_pkgs=$(apt-cache showsrc systemd | grep -m 1 -E '^Binary:' | cut -d ':' -f 2 | tr -d ,)
+    local _files=""
+    for deb in $_systemd_pkgs; do
+        _files=$(dpkg-query -L $deb 2>/dev/null) || continue
+        ddebug "Install debian files from package $deb"
+        for file in $_files; do
+            [ -e "$file" ] || continue
+            [ -d "$file" ] && continue
+            inst $file
+        done
+    done
+}
+
+install_distro_systemd() {
+    ddebug "Install distro systemd"
+
+    if [ "$LOOKS_LIKE_DEBIAN" ]; then
+        install_debian_systemd
+    else
+        dfatal "NO_BUILD not supported for this distro"
+        exit 1
+    fi
+}
+
+install_systemd() {
+    if [ "$NO_BUILD" ]; then
+        install_distro_systemd
+    else
+        install_compiled_systemd
+    fi
+
     # remove unneeded documentation
     rm -fr $initdir/usr/share/{man,doc}