diff --git a/doc/manual/src/contributing/testing.md b/doc/manual/src/contributing/testing.md
index 3d75ebe7b..0b45b88a3 100644
--- a/doc/manual/src/contributing/testing.md
+++ b/doc/manual/src/contributing/testing.md
@@ -133,17 +133,17 @@ ran test tests/functional/${testName}.sh... [PASS]
 or without `make`:
 
 ```shell-session
-$ ./mk/run-test.sh tests/functional/${testName}.sh
+$ ./mk/run-test.sh tests/functional/${testName}.sh tests/functional/init.sh
 ran test tests/functional/${testName}.sh... [PASS]
 ```
 
 To see the complete output, one can also run:
 
 ```shell-session
-$ ./mk/debug-test.sh tests/functional/${testName}.sh
-+ foo
+$ ./mk/debug-test.sh tests/functional/${testName}.sh tests/functional/init.sh
++(${testName}.sh:1) foo
 output from foo
-+ bar
++(${testName}.sh:2) bar
 output from bar
 ...
 ```
@@ -175,7 +175,7 @@ edit it like so:
 Then, running the test with `./mk/debug-test.sh` will drop you into GDB once the script reaches that point:
 
 ```shell-session
-$ ./mk/debug-test.sh tests/functional/${testName}.sh
+$ ./mk/debug-test.sh tests/functional/${testName}.sh tests/functional/init.sh
 ...
 + gdb blash blub
 GNU gdb (GDB) 12.1
diff --git a/mk/common-test.sh b/mk/common-test.sh
index 7ab25febf..00ccd1584 100644
--- a/mk/common-test.sh
+++ b/mk/common-test.sh
@@ -1,15 +1,27 @@
-test_dir=tests/functional
+# Remove overall test dir (at most one of the two should match) and
+# remove file extension.
+test_name=$(echo -n "$test" | sed \
+    -e "s|^unit-test-data/||" \
+    -e "s|^tests/functional/||" \
+    -e "s|\.sh$||" \
+    )
 
-test=$(echo -n "$test" | sed -e "s|^$test_dir/||")
-
-TESTS_ENVIRONMENT=("TEST_NAME=${test%.*}" 'NIX_REMOTE=')
+TESTS_ENVIRONMENT=(
+    "TEST_NAME=$test_name"
+    'NIX_REMOTE='
+    'PS4=+(${BASH_SOURCE[0]-$0}:$LINENO) '
+)
 
 : ${BASH:=/usr/bin/env bash}
 
+run () {
+   cd "$(dirname $1)" && env "${TESTS_ENVIRONMENT[@]}" $BASH -x -e -u -o pipefail $(basename $1)
+}
+
 init_test () {
-   cd "$test_dir" && env "${TESTS_ENVIRONMENT[@]}" $BASH -e init.sh 2>/dev/null > /dev/null
+   run "$init" 2>/dev/null > /dev/null
 }
 
 run_test_proper () {
-   cd "$test_dir/$(dirname $test)" && env "${TESTS_ENVIRONMENT[@]}" $BASH -e $(basename $test)
+   run "$test"
 }
diff --git a/mk/debug-test.sh b/mk/debug-test.sh
index b5b628ecd..52482c01e 100755
--- a/mk/debug-test.sh
+++ b/mk/debug-test.sh
@@ -3,9 +3,12 @@
 set -eu -o pipefail
 
 test=$1
+init=${2-}
 
 dir="$(dirname "${BASH_SOURCE[0]}")"
 source "$dir/common-test.sh"
 
-(init_test)
+if [ -n "$init" ]; then
+    (init_test)
+fi
 run_test_proper
diff --git a/mk/lib.mk b/mk/lib.mk
index e86a7f1a4..49abe9862 100644
--- a/mk/lib.mk
+++ b/mk/lib.mk
@@ -122,14 +122,15 @@ $(foreach script, $(bin-scripts), $(eval $(call install-program-in,$(script),$(b
 $(foreach script, $(bin-scripts), $(eval programs-list += $(script)))
 $(foreach script, $(noinst-scripts), $(eval programs-list += $(script)))
 $(foreach template, $(template-files), $(eval $(call instantiate-template,$(template))))
+install_test_init=tests/functional/init.sh
 $(foreach test, $(install-tests), \
-  $(eval $(call run-install-test,$(test))) \
+  $(eval $(call run-test,$(test),$(install_test_init))) \
   $(eval installcheck: $(test).test))
 $(foreach test-group, $(install-tests-groups), \
-  $(eval $(call run-install-test-group,$(test-group))) \
+  $(eval $(call run-test-group,$(test-group),$(install_test_init))) \
   $(eval installcheck: $(test-group).test-group) \
   $(foreach test, $($(test-group)-tests), \
-    $(eval $(call run-install-test,$(test))) \
+    $(eval $(call run-test,$(test),$(install_test_init))) \
     $(eval $(test-group).test-group: $(test).test)))
 
 $(foreach file, $(man-pages), $(eval $(call install-data-in, $(file), $(mandir)/man$(patsubst .%,%,$(suffix $(file))))))
diff --git a/mk/run-test.sh b/mk/run-test.sh
index 1a1d65930..da9c5a473 100755
--- a/mk/run-test.sh
+++ b/mk/run-test.sh
@@ -8,6 +8,7 @@ yellow=""
 normal=""
 
 test=$1
+init=${2-}
 
 dir="$(dirname "${BASH_SOURCE[0]}")"
 source "$dir/common-test.sh"
@@ -21,7 +22,9 @@ if [ -t 1 ]; then
 fi
 
 run_test () {
-    (init_test 2>/dev/null > /dev/null)
+    if [ -n "$init" ]; then
+        (init_test 2>/dev/null > /dev/null)
+    fi
     log="$(run_test_proper 2>&1)" && status=0 || status=$?
 }
 
diff --git a/mk/tests.mk b/mk/tests.mk
index ec8128bdf..bac9b704a 100644
--- a/mk/tests.mk
+++ b/mk/tests.mk
@@ -2,19 +2,22 @@
 
 test-deps =
 
-define run-install-test
+define run-bash
 
-  .PHONY: $1.test
-  $1.test: $1 $(test-deps)
-	@env BASH=$(bash) $(bash) mk/run-test.sh $1 < /dev/null
-
-  .PHONY: $1.test-debug
-  $1.test-debug: $1 $(test-deps)
-	@env BASH=$(bash) $(bash) mk/debug-test.sh $1 < /dev/null
+  .PHONY: $1
+  $1: $2
+	@env BASH=$(bash) $(bash) $3 < /dev/null
 
 endef
 
-define run-install-test-group
+define run-test
+
+  $(eval $(call run-bash,$1.test,$1 $(test-deps),mk/run-test.sh $1 $2))
+  $(eval $(call run-bash,$1.test-debug,$1 $(test-deps),mk/debug-test.sh $1 $2))
+
+endef
+
+define run-test-group
 
   .PHONY: $1.test-group
 
diff --git a/tests/functional/common/vars-and-functions.sh.in b/tests/functional/common/vars-and-functions.sh.in
index 967d6be54..848988af9 100644
--- a/tests/functional/common/vars-and-functions.sh.in
+++ b/tests/functional/common/vars-and-functions.sh.in
@@ -4,7 +4,7 @@ if [[ -z "${COMMON_VARS_AND_FUNCTIONS_SH_SOURCED-}" ]]; then
 
 COMMON_VARS_AND_FUNCTIONS_SH_SOURCED=1
 
-export PS4='+(${BASH_SOURCE[0]-$0}:$LINENO) '
+set +x
 
 export TEST_ROOT=$(realpath ${TMPDIR:-/tmp}/nix-test)/${TEST_NAME:-default/tests\/functional//}
 export NIX_STORE_DIR