Allow more time for CI events test (#22589)

CI is sometimes slow, so 100ms was not enough time for all events
to be sent and processed in `http/events_test.go`.

We bumped that timeout to a full 1 second, but also added a trick at
the end to shorten the timeout once the expected number of events
have been receieved. This way, once the test has passed, we only
wait 100ms for any "extra" events to make the test fail, instead
of waiting for the full 1 second before we let the test pass. This
should keep the test relatively fast, while still allowing for it to
be slow sometimes.

http/events_test.go

@@ -235,7 +235,8 @@ func TestEventsSubscribeNamespaces(t *testing.T) {
 				conn.Close(websocket.StatusNormalClosure, "")
 			})
 			sendEvents()
-			ctx, cancel := context.WithTimeout(ctx, 100*time.Millisecond)
+			// CI is sometimes slow, so this timeout is high initially
+			ctx, cancel := context.WithTimeout(ctx, 1*time.Second)
 			defer cancel()
 			gotEvents := 0
 			for {
@@ -250,6 +251,14 @@ func TestEventsSubscribeNamespaces(t *testing.T) {
 				}
 				t.Log(string(msg))
 				gotEvents += 1
+
+				// if we got as many as we expect, shorten the test so we don't waste time,
+				// but still allow time for "extra" events to come in and make us fail
+				if gotEvents == testCase.expectedEvents {
+					ctx2, cancel2 := context.WithTimeout(ctx, 100*time.Millisecond)
+					t.Cleanup(cancel2)
+					ctx = ctx2
+				}
 			}
 			assert.Equal(t, testCase.expectedEvents, gotEvents)
 		})