test: update test and test helpers

Test helpers simplified since we now handle test waiting in the
queueUpdate function of the resize handle.
Column resizing test updated to affect multiple columns and more
explicitly check the width of the adjusted columns, not just verify
the delta.

ember-headless-table/src/test-support/index.ts

@@ -28,18 +28,9 @@ export function createHelpers(selectors: Selectors) {
 
     triggerEvent(element, 'mousedown', { clientX: startX, button: 0 });
     triggerEvent(element, 'mousemove', { clientX: targetX, button: 0 });
-
-    await new Promise((resolve) => setTimeout(resolve, 50));
-
     triggerEvent(element, 'mouseup', { clientX: targetX, button: 0 });
 
     await settled();
-
-    /**
-     * This has been super finnicky... :(
-     */
-    await new Promise((resolve) => setTimeout(resolve, 100));
-    await requestAnimationFrameSettled();
   }
 
   function horizontalScrollElement() {

test-app/tests/plugins/column-resizing/rendering-test.gts

@@ -297,9 +297,7 @@ module('Plugins | resizing', function (hooks) {
       }, 'All column preferences reset');
     });
 
-    test('it resizes each column', async function (assert) {
-      // Columns are set to equal widths so each of the four columns
-      // will initially be 250px wide in the 1000px wide container
+    test('it resizes each column and persists the new widths in the preferences', async function (assert) {
       ctx.setContainerWidth(1000);
       await render(
         <template>
@@ -314,30 +312,35 @@ module('Plugins | resizing', function (hooks) {
       debugAssert(`columnC doesn't exist`, columnC);
       debugAssert(`columnD doesn't exist`, columnD);
 
+      assert.equal(width(columnA), 300, 'col A has expected width before resize');
+      assert.equal(width(columnB), 250, 'col B has expected width before resize');
+      assert.equal(width(columnC), 250, 'col C has expected width before resize');
+      assert.equal(width(columnD), 200, 'col D has expected width before resize');
+
       await requestAnimationFrameSettled();
 
-      await assertChanges(
-        () => dragRight(columnB, 50),
-        [
-          { value: () => width(columnA), by: 50, msg: 'width of A increased by 50' },
-          { value: () => width(columnB), by: -50, msg: 'width of B decreased by 50' },
-          { value: () => width(columnC), by: 0, msg: 'width of C unchanged' },
-          { value: () => width(columnD), by: 0, msg: 'width of D unchanged' },
-        ]
-      );
+      // move the the resize handler between columns A & B 200px to the right
+      // increasing the width of column A and decreasing the width of columns
+      // to the right , while respecting the min width (128px)
+      await dragRight(columnB, 200);
+
+      assert.equal(width(columnA), 500, 'col A has expected width after resize');
+      assert.equal(width(columnB), 128, 'col B has expected width after resize');
+      assert.equal(width(columnC), 172, 'col C has expected width after resize');
+      assert.equal(width(columnD), 200, 'col D has expected width after resize');
 
       assert.deepEqual(preferences, {
         "plugins": {
           "ColumnResizing": {
             "columns": {
               "A": {
-                "width": "350"
+                "width": "500"
               },
               "B": {
-                "width": "200"
+                "width": "128"
               },
               "C": {
-                "width": "250"
+                "width": "172"
               },
               "D": {
                 "width": "200"