meson: utilize test priority with sufficiently new meson

+ it's more efficient to schedule longer tests before shorter tests
- we get a warning (if meson is new enough to use priorities)

Priority numbers: I took the config tests as baseline.
I didn't touch tests with "is_parallel: false".

.gitlab-ci.yml

@@ -85,7 +85,7 @@ archive:
 build:
   <<: *build
   script:
-    - meson build_ci --default-library=static --prefix=$PREFIX -Dwerror=true -Dextra_tests=enabled --fatal-meson-warnings
+    - meson build_ci --default-library=static --prefix=$PREFIX -Dwerror=true -Dextra_tests=enabled
     - ninja -C build_ci
     - ninja -C build_ci install >/dev/null
     - ${MESON_TEST} --suite unit --suite config --suite dnstap --no-suite snowflake

ci/debian-buster/Dockerfile

@@ -136,3 +136,8 @@ RUN wget -O /var/opt/scanner.zip https://binaries.sonarsource.com/Distribution/s
 RUN unzip -d /var/opt /var/opt/wrapper.zip
 RUN unzip -d /var/opt /var/opt/scanner.zip
 ENV PATH "$PATH:/var/opt/build-wrapper-linux-x86:/var/opt/sonar-scanner-4.4.0.2170-linux/bin"
+
+# let's get newer meson from backports
+RUN echo 'deb http://deb.debian.org/debian buster-backports main' > /etc/apt/sources.list.d/backports.list
+RUN apt-get update -qq
+RUN apt-get -t buster-backports install -y -qqq meson

tests/dnstap/meson.build

@@ -5,5 +5,7 @@ test('dnstap',
   args: [ sbin_dir / 'kresd' ],
   suite: [ 'postinstall', 'dnstap' ],
   timeout: 120, # it may need to fetch go packages, etc.
+  # it takes relatively long time
+  kwargs: meson.version().version_compare('<0.52') ? {} : { 'priority': 5 },
 )
 

tests/unit/meson.build

@@ -29,5 +29,7 @@ foreach unit_test : unit_tests
     'unit.' + unit_test[0],
     exec_test,
     suite: 'unit',
+    # they take very short time
+    kwargs: meson.version().version_compare('<0.52') ? {} : { 'priority': -5 },
   )
 endforeach