From e27bdec97bca2a41a18029a6910d3ba27fe2dcc9 Mon Sep 17 00:00:00 2001
From: Josh Kelley <joshkel@gmail.com>
Date: Wed, 13 Oct 2021 23:27:42 -0400
Subject: [PATCH] Add a regression test for #9653; fix `toHaveSize` usage

---
 test/specs/core.controller.tests.js |  2 +-
 test/specs/plugin.tooltip.tests.js  | 42 +++++++++++++++++++++++++++++
 2 files changed, 43 insertions(+), 1 deletion(-)

diff --git a/test/specs/core.controller.tests.js b/test/specs/core.controller.tests.js
index 48c1586a8cd..3b165b3b7dc 100644
--- a/test/specs/core.controller.tests.js
+++ b/test/specs/core.controller.tests.js
@@ -1926,7 +1926,7 @@ describe('Chart', function() {
     });
     it('cleans up metasets when the chart is destroyed', function() {
       this.chart.destroy();
-      expect(this.chart._metasets.length).toHaveSize(0);
+      expect(this.chart._metasets).toEqual([]);
     });
   });
 
diff --git a/test/specs/plugin.tooltip.tests.js b/test/specs/plugin.tooltip.tests.js
index 9cf619c5efa..ef0945d9537 100644
--- a/test/specs/plugin.tooltip.tests.js
+++ b/test/specs/plugin.tooltip.tests.js
@@ -1555,6 +1555,48 @@ describe('Plugin.Tooltip', function() {
       chart.tooltip.setActiveElements([{datasetIndex: 0, index: 0}], {x: 0, y: 0});
       expect(chart.tooltip.getActiveElements()[0].element).toBe(meta.data[0]);
     });
+
+    it('should update active elements when datasets are removed and added', async function() {
+      var dataset = {
+        label: 'Dataset 1',
+        data: [10, 20, 30],
+        pointHoverBorderColor: 'rgb(255, 0, 0)',
+        pointHoverBackgroundColor: 'rgb(0, 255, 0)'
+      };
+      var chart = window.acquireChart({
+        type: 'line',
+        data: {
+          datasets: [dataset],
+          labels: ['Point 1', 'Point 2', 'Point 3']
+        },
+        options: {
+          plugins: {
+            tooltip: {
+              mode: 'nearest',
+              intersect: true
+            }
+          }
+        }
+      });
+
+      var meta = chart.getDatasetMeta(0);
+      var point = meta.data[1];
+      var expectedPoint = jasmine.objectContaining({datasetIndex: 0, index: 1});
+
+      await jasmine.triggerMouseEvent(chart, 'mousemove', point);
+
+      expect(chart.tooltip.getActiveElements()).toEqual([expectedPoint]);
+
+      chart.data.datasets = [];
+      chart.update();
+
+      expect(chart.tooltip.getActiveElements()).toEqual([]);
+
+      chart.data.datasets = [dataset];
+      chart.update();
+
+      expect(chart.tooltip.getActiveElements()).toEqual([expectedPoint]);
+    });
   });
 
   describe('events', function() {