diff --git a/src/kernel-install/kernel-install.c b/src/kernel-install/kernel-install.c
index 408de8a0e5..a937d03166 100644
--- a/src/kernel-install/kernel-install.c
+++ b/src/kernel-install/kernel-install.c
@@ -404,15 +404,16 @@ static int context_set_path_strv(Context *c, char* const* strv, const char *sour
 
 static int context_set_plugins(Context *c, const char *s, const char *source) {
         _cleanup_strv_free_ char **v = NULL;
+        int r;
 
         assert(c);
 
         if (c->plugins || !s)
                 return 0;
 
-        v = strv_split(s, NULL);
-        if (!v)
-                return log_oom();
+        r = strv_split_full(&v, s, NULL, EXTRACT_UNQUOTE);
+        if (r < 0)
+                return log_error_errno(r, "Failed to parse plugin paths from %s: %m", source);
 
         return context_set_path_strv(c, v, source, "plugins", &c->plugins);
 }
diff --git a/src/kernel-install/test-kernel-install.sh b/src/kernel-install/test-kernel-install.sh
index 0e41979878..51d618e650 100755
--- a/src/kernel-install/test-kernel-install.sh
+++ b/src/kernel-install/test-kernel-install.sh
@@ -46,7 +46,13 @@ echo 'DTBDTBDTBDTB' >"$D/sources/subdir/whatever.dtb"
 
 export KERNEL_INSTALL_CONF_ROOT="$D/sources"
 # We "install" multiple plugins, but control which ones will be active via install.conf.
-export KERNEL_INSTALL_PLUGINS="${ukify_install} ${loaderentry_install} ${uki_copy_install}"
+KERNEL_INSTALL_PLUGINS="'${loaderentry_install}' '${uki_copy_install}'"
+if [[ -n "$ukify_install" ]]; then
+    # shellcheck disable=SC2089
+    KERNEL_INSTALL_PLUGINS="'${ukify_install}' $KERNEL_INSTALL_PLUGINS"
+fi
+# shellcheck disable=SC2090
+export KERNEL_INSTALL_PLUGINS
 export BOOT_ROOT="$D/boot"
 export BOOT_MNT="$D/boot"
 export MACHINE_ID='3e0484f3634a418b8e6a39e8828b03e3'
diff --git a/src/test/test-compress.c b/src/test/test-compress.c
index 868b862dc7..86311c6217 100644
--- a/src/test/test-compress.c
+++ b/src/test/test-compress.c
@@ -197,7 +197,7 @@ _unused_ static void test_compress_stream(const char *compression,
         ASSERT_OK(compress(src, dst, -1, &uncompressed_size));
 
         if (cat) {
-                assert_se(asprintf(&cmd, "%s %s | diff %s -", cat, pattern, srcfile) > 0);
+                assert_se(asprintf(&cmd, "%s %s | diff '%s' -", cat, pattern, srcfile) > 0);
                 assert_se(system(cmd) == 0);
         }
 
@@ -212,7 +212,7 @@ _unused_ static void test_compress_stream(const char *compression,
         r = decompress(dst, dst2, st.st_size);
         assert_se(r == 0);
 
-        assert_se(asprintf(&cmd2, "diff %s %s", srcfile, pattern2) > 0);
+        assert_se(asprintf(&cmd2, "diff '%s' %s", srcfile, pattern2) > 0);
         assert_se(system(cmd2) == 0);
 
         log_debug("/* test faulty decompression */");
diff --git a/src/udev/test-udev-spawn.c b/src/udev/test-udev-spawn.c
index 7cbccf32a6..a6079e3c61 100644
--- a/src/udev/test-udev-spawn.c
+++ b/src/udev/test-udev-spawn.c
@@ -52,7 +52,8 @@ static void test_event_spawn_self(const char *self, const char *arg, bool with_p
 
         log_debug("/* %s(%s, %s) */", __func__, arg, yes_no(with_pidfd));
 
-        assert_se(cmd = strjoin(self, " ", arg));
+        /* 'self' may contain spaces, hence needs to be quoted. */
+        assert_se(cmd = strjoin("'", self, "' ", arg));
 
         test_event_spawn_core(with_pidfd, cmd, result_buf, BUF_SIZE);
 
diff --git a/test/test-compare-versions.sh b/test/test-compare-versions.sh
index c40208be60..e9acd9cbee 100755
--- a/test/test-compare-versions.sh
+++ b/test/test-compare-versions.sh
@@ -4,32 +4,32 @@ set -e
 
 ANALYZE="${1:-systemd-analyze}"
 
-$ANALYZE compare-versions 1 lt 2
-$ANALYZE compare-versions 1 '<' 2
-$ANALYZE compare-versions 1 le 2
-$ANALYZE compare-versions 1 '<=' 2
-$ANALYZE compare-versions 1 ne 2
-$ANALYZE compare-versions 1 '!=' 2
-( ! $ANALYZE compare-versions 1 ge 2 )
-( ! $ANALYZE compare-versions 1 '>=' 2 )
-( ! $ANALYZE compare-versions 1 eq 2 )
-( ! $ANALYZE compare-versions 1 '==' 2 )
-( ! $ANALYZE compare-versions 1 gt 2 )
-( ! $ANALYZE compare-versions 1 '>' 2 )
+"$ANALYZE" compare-versions 1 lt 2
+"$ANALYZE" compare-versions 1 '<' 2
+"$ANALYZE" compare-versions 1 le 2
+"$ANALYZE" compare-versions 1 '<=' 2
+"$ANALYZE" compare-versions 1 ne 2
+"$ANALYZE" compare-versions 1 '!=' 2
+( ! "$ANALYZE" compare-versions 1 ge 2 )
+( ! "$ANALYZE" compare-versions 1 '>=' 2 )
+( ! "$ANALYZE" compare-versions 1 eq 2 )
+( ! "$ANALYZE" compare-versions 1 '==' 2 )
+( ! "$ANALYZE" compare-versions 1 gt 2 )
+( ! "$ANALYZE" compare-versions 1 '>' 2 )
 
-test "$($ANALYZE compare-versions 1 2)" = '1 < 2'
-test "$($ANALYZE compare-versions 2 2)" = '2 == 2'
-test "$($ANALYZE compare-versions 2 1)" = '2 > 1'
-test "$($ANALYZE compare-versions '' '')" = "'' == ''"
+test "$("$ANALYZE" compare-versions 1 2)" = '1 < 2'
+test "$("$ANALYZE" compare-versions 2 2)" = '2 == 2'
+test "$("$ANALYZE" compare-versions 2 1)" = '2 > 1'
+test "$("$ANALYZE" compare-versions '' '')" = "'' == ''"
 
 set +e
 
-$ANALYZE compare-versions 1 2; ret1=$?
-$ANALYZE compare-versions 2 2; ret2=$?
-$ANALYZE compare-versions 2 1; ret3=$?
+"$ANALYZE" compare-versions 1 2; ret1=$?
+"$ANALYZE" compare-versions 2 2; ret2=$?
+"$ANALYZE" compare-versions 2 1; ret3=$?
 
 set -e
 
-test $ret1 == 12
-test $ret2 == 0
-test $ret3 == 11
+test "$ret1" == 12
+test "$ret2" == 0
+test "$ret3" == 11
diff --git a/test/test-fstab-generator.sh b/test/test-fstab-generator.sh
index af8fa7c226..24a2533f16 100755
--- a/test/test-fstab-generator.sh
+++ b/test/test-fstab-generator.sh
@@ -44,9 +44,9 @@ test_one() (
     fi
 
     if [[ "${input##*/}" =~ \.fstab\.input ]]; then
-        SYSTEMD_LOG_LEVEL=debug SYSTEMD_IN_INITRD="$initrd" SYSTEMD_SYSFS_CHECK=no SYSTEMD_PROC_CMDLINE="fstab=yes root=fstab" SYSTEMD_FSTAB="$input" SYSTEMD_SYSROOT_FSTAB="/dev/null" $generator "$out" "$out" "$out"
+        SYSTEMD_LOG_LEVEL=debug SYSTEMD_IN_INITRD="$initrd" SYSTEMD_SYSFS_CHECK=no SYSTEMD_PROC_CMDLINE="fstab=yes root=fstab" SYSTEMD_FSTAB="$input" SYSTEMD_SYSROOT_FSTAB="/dev/null" "$generator" "$out" "$out" "$out"
     else
-        SYSTEMD_LOG_LEVEL=debug SYSTEMD_IN_INITRD="$initrd" SYSTEMD_SYSFS_CHECK=no SYSTEMD_PROC_CMDLINE="fstab=no $(cat "$input")" $generator "$out" "$out" "$out"
+        SYSTEMD_LOG_LEVEL=debug SYSTEMD_IN_INITRD="$initrd" SYSTEMD_SYSFS_CHECK=no SYSTEMD_PROC_CMDLINE="fstab=no $(cat "$input")" "$generator" "$out" "$out" "$out"
     fi
 
     # The option x-systemd.growfs creates symlink to system's systemd-growfs@.service in .mount.wants directory.
diff --git a/test/test-sysusers.sh.in b/test/test-sysusers.sh.in
index 9af253f6c7..fdeae2c898 100755
--- a/test/test-sysusers.sh.in
+++ b/test/test-sysusers.sh.in
@@ -53,7 +53,7 @@ for f in $(find "$SOURCE"/test-*.input | sort -V); do
     echo "*** Running $f"
     prepare_testdir "${f%.input}"
     cp "$f" "$TESTDIR/usr/lib/sysusers.d/test.conf"
-    $SYSUSERS --root="$TESTDIR"
+    "$SYSUSERS" --root="$TESTDIR"
 
     compare "${f%.*}" ""
 done
@@ -62,7 +62,7 @@ for f in $(find "$SOURCE"/test-*.input | sort -V); do
     echo "*** Running $f on stdin"
     prepare_testdir "${f%.input}"
     touch "$TESTDIR/etc/sysusers.d/test.conf"
-    $SYSUSERS --root="$TESTDIR" - <"$f"
+    "$SYSUSERS" --root="$TESTDIR" - <"$f"
 
     compare "${f%.*}" "on stdin"
 done
@@ -72,9 +72,9 @@ for f in $(find "$SOURCE"/test-*.input | sort -V); do
     prepare_testdir "${f%.input}"
     touch "$TESTDIR/etc/sysusers.d/test.conf"
     # this overrides test.conf which is masked on disk
-    $SYSUSERS --root="$TESTDIR" --replace=/etc/sysusers.d/test.conf - <"$f"
+    "$SYSUSERS" --root="$TESTDIR" --replace=/etc/sysusers.d/test.conf - <"$f"
     # this should be ignored
-    $SYSUSERS --root="$TESTDIR" --replace=/usr/lib/sysusers.d/test.conf - <"$SOURCE/test-1.input"
+    "$SYSUSERS" --root="$TESTDIR" --replace=/usr/lib/sysusers.d/test.conf - <"$SOURCE/test-1.input"
 
     compare "${f%.*}" "on stdin with --replace"
 done
@@ -84,9 +84,9 @@ echo "*** Testing --inline"
 prepare_testdir "$SOURCE/inline"
 # copy a random file to make sure it is ignored
 cp "$f" "$TESTDIR/etc/sysusers.d/confuse.conf"
-$SYSUSERS --root="$TESTDIR" --inline \
-          "u     u1   222 -     - /bin/zsh" \
-          "g     g1   111"
+"$SYSUSERS" --root="$TESTDIR" --inline \
+            "u     u1   222 -     - /bin/zsh" \
+            "g     g1   111"
 
 compare "$SOURCE/inline" "(--inline)"
 
@@ -95,19 +95,19 @@ echo "*** Testing --inline with --replace"
 prepare_testdir "$SOURCE/inline"
 # copy a random file to make sure it is ignored
 cp "$f" "$TESTDIR/etc/sysusers.d/confuse.conf"
-$SYSUSERS --root="$TESTDIR" \
-          --inline \
-          --replace=/etc/sysusers.d/confuse.conf \
-          "u     u1   222 -     - /bin/zsh" \
-          "g     g1   111"
+"$SYSUSERS" --root="$TESTDIR" \
+            --inline \
+            --replace=/etc/sysusers.d/confuse.conf \
+            "u     u1   222 -     - /bin/zsh" \
+            "g     g1   111"
 
 compare "$SOURCE/inline" "(--inline --replace=…)"
 
 echo "*** Testing --inline with no /etc"
 rm -rf "${TESTDIR:?}/etc"
-$SYSUSERS --root="$TESTDIR" --inline \
-          "u     u1   222 -     - /bin/zsh" \
-          "g     g1   111"
+"$SYSUSERS" --root="$TESTDIR" --inline \
+            "u     u1   222 -     - /bin/zsh" \
+            "g     g1   111"
 
 compare "$SOURCE/inline" "(--inline)"
 
@@ -136,7 +136,7 @@ for f in $(find "$SOURCE"/test-*.input | sort -V); do
     echo "*** Running $f (with login.defs)"
     prepare_testdir "${f%.input}"
     cp "$f" "$TESTDIR/usr/lib/sysusers.d/test.conf"
-    $SYSUSERS --root="$TESTDIR"
+    "$SYSUSERS" --root="$TESTDIR"
 
     # shellcheck disable=SC2050
     [ @ENABLE_COMPAT_MUTABLE_UID_BOUNDARIES@ = 1 ] && bound=555 || bound=$system_guid_max
@@ -152,7 +152,7 @@ for f in $(find "$SOURCE"/test-*.input | sort -V); do
     echo "*** Running $f (with login.defs symlinked)"
     prepare_testdir "${f%.input}"
     cp "$f" "$TESTDIR/usr/lib/sysusers.d/test.conf"
-    $SYSUSERS --root="$TESTDIR"
+    "$SYSUSERS" --root="$TESTDIR"
 
     # shellcheck disable=SC2050
     [ @ENABLE_COMPAT_MUTABLE_UID_BOUNDARIES@ = 1 ] && bound=555 || bound=$system_guid_max
@@ -166,7 +166,7 @@ for f in $(find "$SOURCE"/unhappy-*.input | sort -V); do
     echo "*** Running test $f"
     prepare_testdir "${f%.input}"
     cp "$f" "$TESTDIR/usr/lib/sysusers.d/test.conf"
-    SYSTEMD_LOG_LEVEL=info $SYSUSERS --root="$TESTDIR" 2>&1 | tail -n1 | sed -r 's/^[^:]+:[^:]+://' >"$TESTDIR/err"
+    SYSTEMD_LOG_LEVEL=info "$SYSUSERS" --root="$TESTDIR" 2>&1 | tail -n1 | sed -r 's/^[^:]+:[^:]+://' >"$TESTDIR/err"
     if ! diff -u "$TESTDIR/err"  "${f%.*}.expected-err"; then
         echo >&2 "**** Unexpected error output for $f"
         cat >&2 "$TESTDIR/err"