Prefer `flat_map` over `map` + `flatten` in specs

Although `flat_map` is equivalent to `map` + `flatten(1)`
(note the level 1) we can apply this same refactoring to all cases.

1 files changed, 2 insertions, 2 deletions

diff --git a/spec/lib/gitlab/prometheus/metric_group_spec.rb b/spec/lib/gitlab/prometheus/metric_group_spec.rb
index 5cc6827488b..a45dd0af91e 100644
--- a/spec/lib/gitlab/prometheus/metric_group_spec.rb
+++ b/spec/lib/gitlab/prometheus/metric_group_spec.rb
@@ -17,7 +17,7 @@ describe Gitlab::Prometheus::MetricGroup do
     end
 
     it 'returns exactly three metric queries' do
-      expect(subject.map(&:metrics).flatten.map(&:id)).to contain_exactly(
+      expect(subject.flat_map(&:metrics).map(&:id)).to contain_exactly(
         common_metric_group_a.id, common_metric_group_b_q1.id,
         common_metric_group_b_q2.id)
     end
@@ -37,7 +37,7 @@ describe Gitlab::Prometheus::MetricGroup do
 
     subject do
       described_class.for_project(other_project)
-        .map(&:metrics).flatten
+        .flat_map(&:metrics)
         .map(&:id)
     end