Encountering the error message "Expected undefined to be truthy" while testing the creation of a Component

Recently, I've been tasked with enhancing my skill set by writing Jasmine/Karma tests for an Angular 9 application. After completing an online tutorial and doing some research via Google, I began working on my initial test cases independently. However, I seem to have hit a roadblock that I'm struggling to overcome.

The HTML code I am working with is as follows:

<div class="container-fluid">
<div class="center">
  <div class="welcome-container">
    <div class="title">PCPlan</div>
  </div>
  <mat-card>
    <div class="login-form">
      <div class="inputs">
        <mat-form-field class="formfield-min-width">
          <input matInput type="text" placeholder="AD Username" [(ngModel)]="model.username" (keyup.enter)="login()" tabindex="0" autofocus="true"/>
          <button mat-button *ngIf="model.username" matSuffix mat-icon-button aria-label="username" (click)="model.username=''" tabindex="-1">
            <i class="fas fa-times-circle"></i>
          </button>
        </mat-form-field>

        <mat-form-field class="formfield-min-width">
          <input matInput type="password" placeholder="Password" [(ngModel)]="model.password" (keyup.enter)="login()" tabindex="0" autofocus="true"/>
          <button mat-button *ngIf="model.password" matSuffix mat-icon-button aria-label="password" (click)="model.password=''" tabindex="-1">
            <i class="fas fa-times-circle"></i>
          </button>
        </mat-form-field>
      </div>

      <button mat-raised-button color="primary" (click)="login()" class="login-button">LOG IN</button>

      <div>
        <div *ngIf="errMsg" style="color:indianred; font-weight: bold">{{errMsg}}</div>
      </div>

    </div>
  </mat-card>
</div>

My .ts file includes the following:

[Insert TypeScript content here]

Lastly, here is a snippet from my spec file:

[Include information about the spec file here]

I am currently facing an issue where the error message "Expected undefined to be truthy" is being displayed. Despite my efforts, I haven't been able to resolve this issue. I suspect there might be some simple mistake that I am overlooking. Any assistance or guidance would be greatly appreciated.

Answer №1

After diving deeper into the code I was testing, I realized it was much more intricate than anything I had encountered in tutorials before. By properly mocking everything in the constructor during beforeEach, I was able to resolve the error that had been plaguing me.

A special thanks goes out to hugomosh for their insightful comment that ultimately guided me towards the solution earlier today.

Answer №2

Upon reviewing the fixture from the beforeEach block (1) and the it-test block (2), it became evident that the fixture is defined after the test block is completed, leading to the failure of the entire test. Initially, the console displayed that the fixture is undefined (statement 2), followed by the appearance of a defined fixture with mocks and other elements (statement 1). It was a peculiar discovery, but I managed to troubleshoot my way out of it.

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