test: add --jobs tests

Testing that parallel execution actually works is a bit difficult, so
the most trivial way of doing it is to just have a bunch of sleep tests
and make sure that they run faster than would be possible if they were
run in serial.

Signed-off-by: Aleksa Sarai <cyphar@cyphar.com>

Dockerfile

@@ -2,8 +2,12 @@ ARG bashver=latest
 
 FROM bash:${bashver}
 
-RUN ln -s /opt/bats/bin/bats /usr/sbin/bats
+# Install parallel and accept the citation notice (we aren't using this in a
+# context where it make sense to cite GNU Parallel).
+RUN apk add --no-cache parallel && \
+    mkdir -p ~/.parallel && touch ~/.parallel/will-cite
 
+RUN ln -s /opt/bats/bin/bats /usr/sbin/bats
 COPY . /opt/bats/
 
 ENTRYPOINT ["bash", "/usr/sbin/bats"]

test/bats.bats

@@ -467,3 +467,19 @@ END_OF_ERR_MSG
   [ "${lines[5]}" = '# bar' ]
   [ "${lines[6]}" = '# baz' ]
 }
+
+@test "parallel test execution with --jobs" {
+  type -p parallel &>/dev/null || skip "--jobs requires GNU parallel"
+
+  SECONDS=0
+  run bats --jobs 10 "$FIXTURE_ROOT/parallel.bats"
+  duration="$SECONDS"
+  [ "$status" -eq 0 ]
+  # Make sure the lines are in-order.
+  [[ "${lines[0]}" == "1..10" ]]
+  for t in {1..10}; do
+    [[ "${lines[$t]}" == "ok $t slow test $t" ]]
+  done
+  # In theory it should take 3s, but let's give it bit of extra time instead.
+  [[ "$duration" -lt 20 ]]
+}

test/fixtures/bats/parallel.bats

@@ -0,0 +1,39 @@
+@test "slow test 1" {
+  sleep 3s
+}
+
+@test "slow test 2" {
+  sleep 3s
+}
+
+@test "slow test 3" {
+  sleep 3s
+}
+
+@test "slow test 4" {
+  sleep 3s
+}
+
+@test "slow test 5" {
+  sleep 3s
+}
+
+@test "slow test 6" {
+  sleep 3s
+}
+
+@test "slow test 7" {
+  sleep 3s
+}
+
+@test "slow test 8" {
+  sleep 3s
+}
+
+@test "slow test 9" {
+  sleep 3s
+}
+
+@test "slow test 10" {
+  sleep 3s
+}

test/fixtures/suite/parallel/parallel1.bats

@@ -0,0 +1 @@
+../../bats/parallel.bats

test/fixtures/suite/parallel/parallel2.bats

@@ -0,0 +1 @@
+../../bats/parallel.bats

test/fixtures/suite/parallel/parallel3.bats

@@ -0,0 +1 @@
+../../bats/parallel.bats

test/fixtures/suite/parallel/parallel4.bats

@@ -0,0 +1 @@
+../../bats/parallel.bats

test/suite.bats

@@ -126,3 +126,23 @@ fixtures suite
   [ "${lines[1]}" = 'ok 1 baz in a' ]
   [ "${lines[2]}" = 'ok 2 bar_in_b' ]
 }
+
+@test "parallel suite execution with --jobs" {
+  type -p parallel &>/dev/null || skip "--jobs requires GNU parallel"
+
+  SECONDS=0
+  run bats --jobs 40 "$FIXTURE_ROOT/parallel"
+  duration="$SECONDS"
+  [ "$status" -eq 0 ]
+  # Make sure the lines are in-order.
+  [[ "${lines[0]}" == "1..40" ]]
+  i=0
+  for s in {1..4}; do
+    for t in {1..10}; do
+      ((++i))
+      [[ "${lines[$i]}" == "ok $i slow test $t" ]]
+    done
+  done
+  # In theory it should take 3s, but let's give it bit of extra time instead.
+  [[ "$duration" -lt 20 ]]
+}