diff --git a/tests/common.sh b/tests/common.sh
index af60285..d333bb8 100644
--- a/tests/common.sh
+++ b/tests/common.sh
@@ -1,12 +1,18 @@
 
-basedir=..
-testdir="$basedir/tests"
-bindir="$basedir"
+basedir=$(cd $srcdir && pwd)
+datadir=$(pwd)
+bindir="$datadir/.."
 
 sbsign=$bindir/sbsign
 sbverify=$bindir/sbverify
 sbattach=$bindir/sbattach
 
-key="$testdir/private-key.rsa"
-cert="$testdir/public-cert.pem"
-image="$testdir/test.pecoff"
+key="$datadir/private-key.rsa"
+cert="$datadir/public-cert.pem"
+image="$datadir/test.pecoff"
+
+tempdir=$(mktemp --directory)
+exit_trap='rm -rf $tempdir'
+trap "$exit_trap" EXIT
+
+cd "$tempdir"
diff --git a/tests/sign-attach-verify.sh b/tests/sign-attach-verify.sh
index 333308e..2040229 100755
--- a/tests/sign-attach-verify.sh
+++ b/tests/sign-attach-verify.sh
@@ -2,11 +2,10 @@
 
 . "$srcdir/common.sh"
 
-sig=test.sig
-signed=test.signed
+sig="test.sig"
+signed="test.signed"
 
-trap 'rm -f "$sig" "$signed"' EXIT
-
-"$sbsign" --cert "$cert" --key "$key" --detached --output $sig "$image"
-"$sbattach" --attach $sig $signed
+"$sbsign" --cert "$cert" --key "$key" --detached --output "$sig" "$image"
+cp "$image" "$signed"
+"$sbattach" --attach "$sig" "$signed"
 "$sbverify" --cert "$cert" "$signed"
diff --git a/tests/sign-verify-detached.sh b/tests/sign-verify-detached.sh
index 02c583e..951e4a3 100755
--- a/tests/sign-verify-detached.sh
+++ b/tests/sign-verify-detached.sh
@@ -2,9 +2,7 @@
 
 . "$srcdir/common.sh"
 
-sig=test.sig
-
-trap 'rm -f "$sig"' EXIT
+sig="test.sig"
 
 "$sbsign" --cert "$cert" --key "$key" --detached --output $sig "$image"
 "$sbverify" --cert "$cert" --detached $sig "$image"
diff --git a/tests/sign-verify.sh b/tests/sign-verify.sh
index bc9bceb..38324e8 100755
--- a/tests/sign-verify.sh
+++ b/tests/sign-verify.sh
@@ -2,5 +2,7 @@
 
 . "$srcdir/common.sh"
 
-"$sbsign" --cert "$cert" --key "$key" --output test.signed "$image"
-"$sbverify" --cert "$cert" test.signed
+signed="test.signed"
+
+"$sbsign" --cert "$cert" --key "$key" --output "$signed" "$image"
+"$sbverify" --cert "$cert" "$signed"