在Angular中进行单元测试时,可以使用Jasmine测试框架和Angular的测试工具来进行指令输入限制的测试。以下是一个示例解决方法:
假设我们有一个自定义指令,该指令限制用户只能输入数字:
import { Directive, ElementRef, HostListener } from '@angular/core';
@Directive({
selector: '[appNumberOnly]'
})
export class NumberOnlyDirective {
constructor(private el: ElementRef) { }
@HostListener('keydown', ['$event'])
onKeyDown(event: KeyboardEvent) {
// 只允许输入数字
if (![46, 8, 9, 27, 13, 110, 190].includes(event.keyCode) && (event.keyCode < 48 || event.keyCode > 57)) {
event.preventDefault();
}
}
}
然后,我们可以使用Jasmine和Angular的测试工具来编写单元测试:
import { TestBed, ComponentFixture } from '@angular/core/testing';
import { Component, DebugElement } from '@angular/core';
import { By } from '@angular/platform-browser';
import { NumberOnlyDirective } from './number-only.directive';
@Component({
template: ``
})
class TestComponent {}
describe('NumberOnlyDirective', () => {
let fixture: ComponentFixture;
let inputEl: DebugElement;
beforeEach(() => {
TestBed.configureTestingModule({
declarations: [NumberOnlyDirective, TestComponent]
});
fixture = TestBed.createComponent(TestComponent);
inputEl = fixture.debugElement.query(By.css('input'));
});
it('should prevent non-numeric input', () => {
inputEl.nativeElement.value = 'abc';
inputEl.triggerEventHandler('keydown', { keyCode: 65 });
expect(inputEl.nativeElement.value).toBe('');
inputEl.nativeElement.value = '123';
inputEl.triggerEventHandler('keydown', { keyCode: 66 });
expect(inputEl.nativeElement.value).toBe('123');
});
it('should allow numeric input', () => {
inputEl.nativeElement.value = '123';
inputEl.triggerEventHandler('keydown', { keyCode: 49 });
expect(inputEl.nativeElement.value).toBe('1231');
inputEl.nativeElement.value = '456';
inputEl.triggerEventHandler('keydown', { keyCode: 50 });
expect(inputEl.nativeElement.value).toBe('4562');
});
});
通过以上测试代码,我们可以测试指令是否正确限制了输入的内容。
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