Function checkNodeDescendants

src/cdk/tree/tree.spec.ts:1692–1709

(node: Element, expectedNode: any[], currentIndex: number)

  }

  function checkNodeDescendants(node: Element, expectedNode: any[], currentIndex: number) {
    let expectedDescendant = 0;

    for (let i = currentIndex + 1; i < expectedTree.length; ++i) {
      if (expectedTree[i].length > expectedNode.length) {
        ++expectedDescendant;
      } else if (expectedTree[i].length === expectedNode.length) {
        break;
      }
    }

    const actualDescendant = getNodes(node).length;
    if (actualDescendant !== expectedDescendant) {
      missedExpectations.push(
        `Expected node descendant num to be ${expectedDescendant} but was ${actualDescendant}`,
      );
    }
  }

  getNodes(treeElement).forEach((node, index) => {
    const expected = expectedTree ? expectedTree[index] : null;