add changelog and spec

2 files changed, 17 insertions, 0 deletions

diff --git a/changelogs/unreleased/38394-smarter-interval.yml b/changelogs/unreleased/38394-smarter-interval.yml
new file mode 100644
index 00000000000..e641534813e
--- /dev/null
+++ b/changelogs/unreleased/38394-smarter-interval.yml
@@ -0,0 +1,5 @@
+---
+title: improve merge request realtime polling performance
+merge_request:
+author:
+type: fixed
diff --git a/spec/javascripts/smart_interval_spec.js b/spec/javascripts/smart_interval_spec.js
index c602eda9560..bc835198242 100644
--- a/spec/javascripts/smart_interval_spec.js
+++ b/spec/javascripts/smart_interval_spec.js
@@ -58,6 +58,18 @@ import '~/smart_interval';
           done();
         }, DEFAULT_LONG_TIMEOUT);
       });
+
+      it('does not increment while waiting for callback', function (done) {
+        const smartInterval = createDefaultSmartInterval({
+          callback: () => new Promise($.noop),
+        });
+
+        setTimeout(() => {
+          const oneInterval = smartInterval.cfg.startingInterval * DEFAULT_INCREMENT_FACTOR;
+          expect(smartInterval.getCurrentInterval()).toEqual(oneInterval);
+          done();
+        }, DEFAULT_SHORT_TIMEOUT);
+      });
     });
 
     describe('Public methods', function () {