diff --git a/dev-ada/langkit/langkit-2018.ebuild b/dev-ada/langkit/langkit-2018.ebuild
index 6fe74a78bc9a8..348ef449845aa 100644
--- a/dev-ada/langkit/langkit-2018.ebuild
+++ b/dev-ada/langkit/langkit-2018.ebuild
@@ -5,7 +5,7 @@ EAPI=6
 
 PYTHON_COMPAT=( python2_7 )
 
-inherit python-single-r1
+inherit python-single-r1 multiprocessing
 
 MYP=${PN}-gpl-${PV}
 
@@ -24,6 +24,7 @@ DEPEND="${PYTHON_DEPS}
 	dev-ada/gnatcoll-bindings[iconv,shared]
 	dev-python/mako
 	dev-python/pyyaml
+	<dev-python/pyyaml-5
 	dev-python/enum34
 	dev-python/funcy
 	dev-python/docutils
@@ -35,7 +36,7 @@ S="${WORKDIR}"/${MYP}-src
 PATCHES=( "${FILESDIR}"/${P}-gentoo.patch )
 
 src_test() {
-	testsuite/testsuite.py --show-error-output | tee testsuite.log
+	testsuite/testsuite.py -j $(makeopts_jobs) --show-error-output | tee testsuite.log
 	grep -q FAILED testsuite.log && die "Test failed"
 }
 
diff --git a/dev-ada/langkit/langkit-2019.ebuild b/dev-ada/langkit/langkit-2019.ebuild
index 1cc699ee20a63..72bcd4d3adbb3 100644
--- a/dev-ada/langkit/langkit-2019.ebuild
+++ b/dev-ada/langkit/langkit-2019.ebuild
@@ -5,7 +5,7 @@ EAPI=7
 
 PYTHON_COMPAT=( python2_7 )
 
-inherit python-single-r1
+inherit python-single-r1 multiprocessing
 
 MYP=${P}-20190510-19B8C
 
@@ -36,7 +36,7 @@ S="${WORKDIR}"/${MYP}-src
 PATCHES=( "${FILESDIR}"/${P}-gentoo.patch )
 
 src_test() {
-	testsuite/testsuite.py --show-error-output | tee testsuite.log
+	testsuite/testsuite.py -j $(makeopts_jobs) --show-error-output | tee testsuite.log
 	grep -q FAILED testsuite.log && die "Test failed"
 }