Angular Karma测试：为什么在未隔离的情况下同一测试会失败？

Question

我有一个Angular组件测试（它仅创建组件“ Edit-base-schema”，没有方法调用），在不进行其他测试的情况下可以正常运行。当我用18个组件执行所有18个测试时，相同的组件测试将失败。有趣的是，此组件在构造函数中没有依赖项注入（没有服务），并且ngOnInit方法为空。你有解释吗？

这是组件：

import { Component, OnInit, Input, ViewChild, ElementRef } from 
'@angular/core';
import { DimensionTree } from '../../swagger/models/dimension-tree';
import { SchemaWithItems } from '../../swagger/models/schema-with- 
items';
import { ZoomData } from '../../svg/svg-zoomable.directive';
import * as d3 from 'd3';
import { environment } from '../../../environments/environment';

@Component({
selector: 'app-edit-base-schema',
templateUrl: './edit-base-schema.component.html',
styleUrls: ['./edit-base-schema.component.scss']
})
export class EditBaseSchemaComponent implements OnInit {
transform: ZoomData = { x: 0, y: 0, k: 1.0 };

@ViewChild('imgSchema') imgSchema: ElementRef;

@ViewChild('svgElement') svgElement: ElementRef;

@ViewChild('svgHoster') svgHoster: ElementRef;

@Input()
schemaId: string;

private _schema: SchemaWithItems;

apiUrl = environment.apiUrl + '/api';

constructor() { }

ngOnInit() {

}


@Input()
get schema(): SchemaWithItems {
  return this._schema;
}

set schema(sc: SchemaWithItems) {
  this._schema = sc;
  if (!sc) {
    return;
}
setTimeout(() => {


  const svgElement: HTMLElement = this.svgHoster.nativeElement;
  const svgElementWidth = svgElement.offsetWidth;
  const svgElementHeight = svgElement.offsetHeight;
  if (svgElementWidth && svgElementHeight) {
    if (sc.imageHeight > svgElementHeight || sc.imageWidth > svgElementWidth) {
      const newK = Math.min(svgElementHeight / sc.imageHeight, svgElementWidth / sc.imageWidth);
      this.transform = {x: 0, y: 0, k: newK};
    }
  }

  }, 10);
}

onDrop($event: any) {
    const isLinkEvent: 'Link' | '' = 
$event.event.dataTransfer.getData('text');

// Coordinates
// The coordinates are relative to the image (not the schema, as the schema is not transformed)
const [x, y] = d3.clientPoint(this.imgSchema.nativeElement, $event.event);
if (isLinkEvent === 'Link') {
  const data = {
    width: 120, height: 80,
    locationX: x,
    locationY: y,
    cssClasses: '',
    itemPrefix: null,
    fontColor: '#000',
    fontFamily: 'Segoe UI', // Windows-only - no problem for empa, and uses browser-default on other systems
    fontSize: 12,
    itemTemplate: '',
    dataNumericId: null,
    url: 'https://www.empa.ch/web/empa',
    schemaItemId: 0,
    openLinkDirectly: true
  };

  this.schema.items.push(data);
}
if (!isLinkEvent) {
  // Dropped $event.element
  const treeData = <DimensionTree>$event.element.data;
  this.schema.items.push({
    width: 120, height: 80,
    locationX: x,
    locationY: y,
    cssClasses: '',
    fontColor: '#000',
    fontFamily: 'Segoe UI', // Windows-only - no problem for empa, and uses browser-default on other systems
    fontSize: 12,
    itemPrefix: treeData.itemPrefix,
    itemTemplate: '',
    schemaItemId: 0
  });
 }
}

getHeight() {
 return window.innerHeight;
}

onItemDelete(item) {
  const index = this.schema.items.indexOf(item);
  const copy = this.schema.items.concat([]);
  copy.splice(index, 1);
  this.schema.items = copy; // Set a copy of it as items
}


allowDrop(element) {
  // Return true/false based on element
  return true;
  }

}