diff --git a/lib/tests/sources.sh b/lib/tests/sources.sh
index e148d023c854..68d21d2aa6d3 100755
--- a/lib/tests/sources.sh
+++ b/lib/tests/sources.sh
@@ -11,7 +11,7 @@ die() {
 if test -n "${TEST_LIB:-}"; then
   NIX_PATH=nixpkgs="$(dirname "$TEST_LIB")"
 else
-  NIX_PATH=nixpkgs="$(cd $(dirname ${BASH_SOURCE[0]})/../..; pwd)"
+  NIX_PATH=nixpkgs="$(cd "$(dirname "${BASH_SOURCE[0]}")/../.."; pwd)"
 fi
 export NIX_PATH
 
@@ -20,7 +20,7 @@ clean_up() {
   rm -rf "$work"
 }
 trap clean_up EXIT
-cd $work
+cd "$work"
 
 touch {README.md,module.o,foo.bar}
 
@@ -30,7 +30,7 @@ touch {README.md,module.o,foo.bar}
 dir="$(nix eval --impure --raw --expr '(with import <nixpkgs/lib>; "${
   cleanSource ./.
 }")')"
-(cd $dir; find) | sort -f | diff -U10 - <(cat <<EOF
+(cd "$dir"; find) | sort -f | diff -U10 - <(cat <<EOF
 .
 ./foo.bar
 ./README.md
@@ -41,7 +41,7 @@ EOF
 dir="$(nix eval --impure --raw --expr '(with import <nixpkgs/lib>; "${
   cleanSourceWith { src = '"$work"'; filter = path: type: ! hasSuffix ".bar" path; }
 }")')"
-(cd $dir; find) | sort -f | diff -U10 - <(cat <<EOF
+(cd "$dir"; find) | sort -f | diff -U10 - <(cat <<EOF
 .
 ./module.o
 ./README.md
@@ -51,7 +51,7 @@ EOF
 dir="$(nix eval --impure --raw --expr '(with import <nixpkgs/lib>; "${
   cleanSourceWith { src = cleanSource '"$work"'; filter = path: type: ! hasSuffix ".bar" path; }
 }")')"
-(cd $dir; find) | sort -f | diff -U10 - <(cat <<EOF
+(cd "$dir"; find) | sort -f | diff -U10 - <(cat <<EOF
 .
 ./README.md
 EOF