diff --git a/hbase-server/src/test/java/org/apache/hadoop/hbase/regionserver/throttle/TestFlushWithThroughputController.java b/hbase-server/src/test/java/org/apache/hadoop/hbase/regionserver/throttle/TestFlushWithThroughputController.java
index 61f9cd4969a..7aaa1538856 100644
--- a/hbase-server/src/test/java/org/apache/hadoop/hbase/regionserver/throttle/TestFlushWithThroughputController.java
+++ b/hbase-server/src/test/java/org/apache/hadoop/hbase/regionserver/throttle/TestFlushWithThroughputController.java
@@ -177,12 +177,18 @@ public class TestFlushWithThroughputController {
       .build());
     hbtu.waitTableAvailable(tableName);
     HRegionServer regionServer = hbtu.getRSForFirstRegionInTable(tableName);
+    double pressure = regionServer.getFlushPressure();
+    LOG.debug("Flush pressure before flushing: " + pressure);
     PressureAwareFlushThroughputController throughputController =
         (PressureAwareFlushThroughputController) regionServer.getFlushThroughputController();
     for (HRegion region : regionServer.getRegions()) {
       region.flush(true);
     }
-    assertEquals(0.0, regionServer.getFlushPressure(), EPSILON);
+    // We used to assert that the flush pressure is zero but after HBASE-15787 or HBASE-18294 we
+    // changed to use heapSize instead of dataSize to calculate the flush pressure, and since
+    // heapSize will never be zero, so flush pressure will never be zero either. So we changed the
+    // assertion here.
+    assertTrue(regionServer.getFlushPressure() < pressure);
     Thread.sleep(5000);
     boolean tablesOnMaster = LoadBalancer.isTablesOnMaster(hbtu.getConfiguration());
     if (tablesOnMaster) {