Jest test of Typescript shows wrong error lines

Question

I am running a sample Jest test on a structure, and I find that the errors in my output summary from Jest are off by a couple of lines.

Package.json

"devDependencies": {
    "@types/jest": "^22.0.1",
    "jest": "^22.1.4",
    "jest-preset-angular": "^5.0.0",
    "ts-jest": "^22.0.1",
    "typescript": "^2.6.2"
},

Output:

Venue › Venue Structure › should have all the structure fields

expect(received).toBeDefined()

Expected value to be defined, instead received
  undefined

  20 |              it('should be an instance of DataStructure', () => {
  21 |                      expect(VenueInfo instanceof DataStructure).toBeTruthy();
> 22 |              })
  23 |
  24 |              it('should have the proper number of data fields', () => {
  25 |                      expect(VenueInfo.NumberOfFields).toBe(14);              // LastUpdated is added automatically

  at src/structures/Venue.spec.ts:22:35

However, the test is question is actually at line 29, based on the text from the it().

Venue.spec.ts:

import { TestBed, ComponentFixture } from '@angular/core/testing';
import { NO_ERRORS_SCHEMA } from '@angular/core';

import { Venue } from './Venue';
import { DataStructure } from '../library/base/DataStructure';

describe('Venue', () => {
    let VenueInfo: Venue;

    beforeEach(() => {
        VenueInfo = new Venue();
    });

    describe('Class', () => {

        it('should be an instance of Venue', () => {
            expect(VenueInfo instanceof Venue).toBeTruthy();    ;
        });

        it('should be an instance of DataStructure', () => {
            expect(VenueInfo instanceof DataStructure).toBeTruthy();
        })

        it('should have the proper number of data fields', () => {
            expect(VenueInfo.NumberOfFields).toBe(14);          });
    });

    describe('Venue Structure', () => {
        it('should have all the structure fields', () => {
            expect(VenueInfo.Key).toBeDefined();
            expect(VenueInfo.Description).toBeDefined();
            expect(VenueInfo.Address1).toBeDefined();
            expect(VenueInfo.Address2).toBeDefined();
            expect(VenueInfo.City).toBeDefined();
            expect(VenueInfo.Province).toBeDefined();
            expect(VenueInfo.Country).toBeDefined();
            expect(VenueInfo.PostalCode).toBeDefined();
            expect(VenueInfo.Telephone).toBeDefined();
            expect(VenueInfo.Latitude).toBeDefined();
            expect(VenueInfo.Longitude).toBeDefined();
            expect(VenueInfo.MajorIntersection).toBeDefined();
            expect(VenueInfo.DartBoards).toBeDefined();
        });
    });
});

tsconfig.json

{
    "compilerOptions": {
        "allowSyntheticDefaultImports": true,
        "declaration": false,
        "emitDecoratorMetadata": true,
        "experimentalDecorators": true,
        "lib": [
            "dom",
            "es2015"
        ],
        "module": "es2015",
        "moduleResolution": "node",
        "sourceMaps": true,
        "target": "es5"
    },
    "include": [
        "src/**/*.ts"
    ],
    "exclude": [
        "node_modules",
        "src/**/*.spec.ts",
        "src/test-config"
    ],
    "compileOnSave": false,
    "atom": {
        "rewriteTsconfig": false
    }
}

From early configurations, I also had a tsconfig.spec.ts in the src directory of my Ionic application, which also has the sourceMaps: true, but does not seem to have any impact.

tsconfig.spec.json (not sure what uses this as I cannot find a reference to the file):

{
    "extends": "../tsconfig.json",
    "compilerOptions": {
        "allowJs": true,
        "module": "commonjs",
        "outDir": "../out-tsc/spec",
        "sourceMaps": true,
        "target": "es5"
    },
    "files": [
        "**/*.ts"
    ],
    "include": [
        "*.spec.ts",
        "**/*.spec.ts",
        "**/*.d.ts",
        "test-config/*.ts",
        "test-config/**/*.ts"
    ]
}

Answer 1

Jest test of Typescript shows wrong error lines

Make sure your tsconfig.json has sourceMap: true