T1264497: DataGrid - fix separator height for grouped columns (DevExpress#28902)

Co-authored-by: Vladimir Bushmanov <[email protected]>

Author: Ambrozy

e2e/testcafe-devextreme/tests/dataGrid/columnResizing.ts

@@ -0,0 +1,69 @@
+import { createScreenshotsComparer } from 'devextreme-screenshot-comparer';
+import DataGrid from 'devextreme-testcafe-models/dataGrid';
+
+import url from '../../helpers/getPageUrl';
+import { createWidget } from '../../helpers/createWidget';
+
+fixture`Column resizing`
+  .page(url(__dirname, '../container.html'));
+
+test('column separator should starts from the parent', async (t) => {
+  const { takeScreenshot, compareResults } = createScreenshotsComparer(t);
+  const dataGrid = new DataGrid('#container');
+  async function makeColumnSeparatorScreenshot(index: number) {
+    await dataGrid.resizeHeader(index, 0, false);
+    await t.expect(await takeScreenshot(`column-separator-${index}.png`)).ok();
+    await t.dispatchEvent(dataGrid.element, 'mouseup');
+  }
+
+  await makeColumnSeparatorScreenshot(1);
+  await makeColumnSeparatorScreenshot(2);
+  await makeColumnSeparatorScreenshot(3);
+  await makeColumnSeparatorScreenshot(4);
+  await makeColumnSeparatorScreenshot(5);
+  await makeColumnSeparatorScreenshot(6);
+  await makeColumnSeparatorScreenshot(7);
+  await makeColumnSeparatorScreenshot(8);
+  await makeColumnSeparatorScreenshot(9);
+
+  await t
+    .expect(compareResults.isValid())
+    .ok(compareResults.errorMessages());
+}).before(async () => createWidget('dxDataGrid', {
+  dataSource: [{
+    ID: 1,
+    Country: 'Brazil',
+    Area: 8515767,
+    Population_Urban: 0.85,
+    Population_Rural: 0.15,
+    Population_Total: 205809000,
+    GDP_Agriculture: 0.054,
+    GDP_Industry: 0.274,
+    GDP_Services: 0.672,
+    GDP_Total: 2353025,
+  }],
+  keyExpr: 'ID',
+  columnWidth: 100,
+  allowColumnResizing: true,
+  showBorders: true,
+  editing: {
+    allowUpdating: true,
+  },
+  columns: ['Country', {
+    dataField: 'Population_Total',
+    visible: false,
+  }, {
+    caption: 'Population',
+    columns: ['Population_Rural', {
+      caption: 'By Sector',
+      columns: ['GDP_Total', {
+        caption: 'not resizable',
+        dataField: 'ID',
+        allowResizing: false,
+      }, 'GDP_Agriculture', 'GDP_Industry'],
+    }],
+  }, {
+    caption: 'Nominal GDP',
+    columns: ['GDP_Total', 'Population_Urban'],
+  }, 'Area'],
+}));