diff --git a/tests/mypy.sh b/tests/mypy.sh
index af0cb055ae305f6dab9dd8896ab572d6f0c97af9..76d73b27ada3cc3675938359b7393238512b1d7f 100755
--- a/tests/mypy.sh
+++ b/tests/mypy.sh
@@ -28,20 +28,19 @@ set -u
 
 if [ -z "${G_TEST_SRCDIR-}" ]; then
     me="$(readlink -f "$0")"
-    srcdir="${me%/*}"
-    G_TEST_SRCDIR="${srcdir%/*}"
+    G_TEST_SRCDIR="${me%/*}"
 fi
 
-cd "$G_TEST_SRCDIR"
+cd "$G_TEST_SRCDIR/.."
 
 export MYPYPATH="${PYTHONPATH:="$(pwd)"}"
 
 i=0
 for script in \
-    "${G_TEST_SRCDIR}"/*.py \
-    "${G_TEST_SRCDIR}"/pressure-vessel-test-ui \
-    "${G_TEST_SRCDIR}"/sysroot/*.py \
-    "${G_TEST_SRCDIR}"/tests/*.py \
+    ./*.py \
+    ./pressure-vessel-test-ui \
+    ./sysroot/*.py \
+    ./tests/*.py \
 ; do
     i=$((i + 1))
     if [ "x${MYPY:="$(command -v mypy || echo false)"}" = xfalse ]; then
diff --git a/tests/pycodestyle.sh b/tests/pycodestyle.sh
index cd33d6bf49fb9ed5fde892fb4d18fabfe05fb72c..2e3b6146cd586a527ceb036ae0098036beb8b762 100755
--- a/tests/pycodestyle.sh
+++ b/tests/pycodestyle.sh
@@ -28,11 +28,10 @@ set -u
 
 if [ -z "${G_TEST_SRCDIR-}" ]; then
     me="$(readlink -f "$0")"
-    srcdir="${me%/*}"
-    G_TEST_SRCDIR="${srcdir%/*}"
+    G_TEST_SRCDIR="${me%/*}"
 fi
 
-cd "$G_TEST_SRCDIR"
+cd "$G_TEST_SRCDIR/.."
 
 if [ "x${PYCODESTYLE:=pycodestyle}" = xfalse ] || \
         [ -z "$(command -v "$PYCODESTYLE")" ]; then
@@ -48,10 +47,10 @@ echo "1..1"
 
 if "${PYCODESTYLE}" \
     --ignore=E402,W503 \
-    "$G_TEST_SRCDIR"/*.py \
-    "${G_TEST_SRCDIR}"/pressure-vessel-test-ui \
-    "${G_TEST_SRCDIR}"/sysroot/*.py \
-    "${G_TEST_SRCDIR}"/tests/*.py \
+    ./*.py \
+    ./pressure-vessel-test-ui \
+    ./sysroot/*.py \
+    ./tests/*.py \
     >&2; then
     echo "ok 1 - $PYCODESTYLE reported no issues"
 else
diff --git a/tests/pyflakes.sh b/tests/pyflakes.sh
index 8da6f8dd7680e27f4284b19a399a0fca8a92203d..5511bfa24b14ca28d8dbd2ecc88aa8a016f4e32d 100755
--- a/tests/pyflakes.sh
+++ b/tests/pyflakes.sh
@@ -28,20 +28,19 @@ set -u
 
 if [ -z "${G_TEST_SRCDIR-}" ]; then
     me="$(readlink -f "$0")"
-    srcdir="${me%/*}"
-    G_TEST_SRCDIR="${srcdir%/*}"
+    G_TEST_SRCDIR="${me%/*}"
 fi
 
-cd "$G_TEST_SRCDIR"
+cd "$G_TEST_SRCDIR/.."
 
 if [ "x${PYFLAKES:=pyflakes3}" = xfalse ] || \
         [ -z "$(command -v "$PYFLAKES")" ]; then
     echo "1..0 # SKIP pyflakes3 not found"
 elif "${PYFLAKES}" \
-    "${G_TEST_SRCDIR}"/*.py \
-    "${G_TEST_SRCDIR}"/pressure-vessel-test-ui \
-    "${G_TEST_SRCDIR}"/sysroot/*.py \
-    "${G_TEST_SRCDIR}"/tests/*.py \
+    ./*.py \
+    ./pressure-vessel-test-ui \
+    ./sysroot/*.py \
+    ./tests/*.py \
     >&2; then
     echo "1..1"
     echo "ok 1 - $PYFLAKES reported no issues"
diff --git a/tests/relocatable-install.py b/tests/relocatable-install.py
index 04897a36881bdee858d61d283fddde5340126d75..2829b243da38dfd85112920ad89c7d9df8b60345 100755
--- a/tests/relocatable-install.py
+++ b/tests/relocatable-install.py
@@ -122,8 +122,10 @@ def check_dependencies(test, relocatable_install, path, is_wrapper=False):
         stdout=subprocess.PIPE,
         universal_newlines=True,
     )
+    stdout = subproc.stdout
+    assert stdout is not None       # for mypy
 
-    for line in subproc.stdout:
+    for line in stdout:
         line = line.strip()
 
         if (
diff --git a/tests/shellcheck.sh b/tests/shellcheck.sh
index 85dbaff91d12c20b8982bc0b632ae9db276d2cf3..f952e51278e76623bb1e09865192c167d4fcec8e 100755
--- a/tests/shellcheck.sh
+++ b/tests/shellcheck.sh
@@ -28,19 +28,18 @@ fi
 
 if [ -z "${G_TEST_SRCDIR-}" ]; then
     me="$(readlink -f "$0")"
-    srcdir="${me%/*}"
-    G_TEST_SRCDIR="${srcdir%/*}"
+    G_TEST_SRCDIR="${me%/*}"
 fi
 
-cd "$G_TEST_SRCDIR"
+cd "$G_TEST_SRCDIR/.."
 
 n=0
 for shell_script in \
-        pressure-vessel-unruntime \
-        pressure-vessel-unruntime-scout \
-        pressure-vessel-unruntime-test-ui \
-        pressure-vessel-locale-gen \
-        tests/*.sh \
+        ./pressure-vessel-unruntime \
+        ./pressure-vessel-unruntime-scout \
+        ./pressure-vessel-unruntime-test-ui \
+        ./pressure-vessel-locale-gen \
+        ./tests/*.sh \
         ; do
     n=$((n + 1))