test: More portable check for dpkg versions

This check should work regardless if dpkg was installed by dpkg
or by a native package manager like RPM or pkg.

Gbp-Dch: ignore

test/integration/framework

@@ -195,6 +195,9 @@ aptinternalplanner() { runapt "${APTINTERNALPLANNER}" "$@"; }
 dpkg() {
 	"${TMPWORKINGDIRECTORY}/rootdir/usr/bin/dpkg" "$@"
 }
+dpkg_version() {
+	command perl -MDpkg -E 'say $Dpkg::PROGVERSION'
+}
 dpkgcheckbuilddeps() {
 	command dpkg-checkbuilddeps --admindir="${TMPWORKINGDIRECTORY}/rootdir/var/lib/dpkg" "$@"
 }

test/integration/test-bug-661537-build-profiles-support

@@ -76,7 +76,7 @@ Building dependency tree...
 }
 
 msgtest 'Check if version of installed dpkg is high enough for' 'build profiles support'
-if dpkg --compare-versions "$(command dpkg-query --showformat='${Version}' --show dpkg)" 'ge' '1.17.14'; then
+if dpkg --compare-versions "$(dpkg_version)" 'ge' '1.17.14'; then
 	msgpass
 	testwithdpkg() {
 		msgtest "Test with" "dpkg-checkbuilddeps -d '$1' -P '$2'"

test/integration/test-bug-769609-triggers-still-pending-after-run

@@ -8,7 +8,7 @@ setupenvironment
 configarchitecture 'amd64'
 
 msgtest 'Check if installed dpkg supports' 'noawait trigger'
-if dpkg-checkbuilddeps -d 'dpkg (>= 1.16.1)' /dev/null; then
+if dpkg --compare-versions "$(dpkg_version)" 'ge' '1.16.1'; then
 	msgpass
 else
 	msgskip 'dpkg version too old'

test/integration/test-no-fds-leaked-to-maintainer-scripts

@@ -29,7 +29,7 @@ buildpackage "$BUILDDIR" 'unstable' 'main' 'native'
 rm -rf "$BUILDDIR"
 
 PKGNAME='fdleaks:all'
-if ! dpkg-checkbuilddeps -d 'dpkg (>= 1.16.2)' /dev/null >/dev/null 2>&1; then
+if dpkg --compare-versions "$(dpkg_version)" 'lt' '1.16.2'; then
 	PKGNAME='fdleaks'
 fi