typescript unit test with import statement fails

[ochemerys]

Environment
Provide version numbers for the following components (information can be retrieved by running tns info in your project folder or by inspecting the package.json of the project):
-- tns doctor returns:

• Component nativescript has 5.0.1 version and is up to date.
• Component tns-core-modules has 5.0.3 version and is up to date.
• Component tns-android has 5.0.0 version and is up to date.
• Component tns-ios has 5.0.0 version and is up to date.
  -- package file:
  --- dependencies

    "nativescript-angular": "~7.0.0",
    "nativescript-theme-core": "~1.0.4",
    "nativescript-unit-test-runner": "^0.3.4",
    "tns-core-modules": "~5.0.2",
--- devDependencies 
    "@angular/compiler-cli": "~7.0.0",
    "@nativescript/schematics": "~0.4.0",
    "@ngtools/webpack": "~7.0.0",
    "@types/chai": "^4.1.7",
    "@types/mocha": "^5.2.5",
    "chai": "4.2.0",
    "karma": "3.1.1",
    "karma-chai": "0.1.0",
    "karma-mocha": "1.3.0",
    "karma-nativescript-launcher": "0.4.0",
    "mocha": "5.2.0",
    "nativescript-dev-typescript": "~0.7.0",
    "nativescript-dev-webpack": "~0.18.0",
    "typescript": "^3.1.6"

Describe the bug
angular application typescript unit test with import statement fails with error:
ReferenceError: Can't find variable: exports

To Reproduce

1. follow document https://docs.nativescript.org/tooling/testing.

tns test init 

and select mocha. Run test

tns test ios --emulator

Test runs successfully.

2. add typing

npm i @types/chai --save-dev

3. create example.spec.ts with content:

import { assert } from 'chai'

describe('Array', function () {
	describe('#indexOf()', function () {
		it('should return -1 when the value is not present', function () {
			assert.equal(-1, [1,2,3].indexOf(5));
			assert.equal(-1, [1,2,3].indexOf(0));
		});
	});
});

tns test ios --emulator

Test fails

4. modify example.spec.ts to remove import statement:

describe('Array', function () {
	describe('#indexOf()', function () {
		it('should return -1 when the value is not present', function () {
			chai.assert.equal(-1, [1,2,3].indexOf(5));
			chai.assert.equal(-1, [1,2,3].indexOf(0));
		});
	});
});

run test 
tns test ios --emulator

Test is successful.

5. modify example.spec.ts to add import statement:

import { AppComponent } from '../app/app.component'
describe('Array', function () {
	describe('#indexOf()', function () {
		it('should return -1 when the value is not present', function () {
			chai.assert.equal(-1, [1,2,3].indexOf(5));
			chai.assert.equal(-1, [1,2,3].indexOf(0));
		});
	});
});

tns test ios --emulator

Test fails again with error:

25 11 2018 12:33:01.031:WARN [NativeScript / 12.1 (12.1; iPhone)]: Adapter did not report total number of specs.
NativeScript / 12.1 (12.1; iPhone)  /base/src/tests/example.spec.js?60ad106197c3f92cbc2e05ab96de86321ec139ae at line 0 FAILED
        ReferenceError: Can't find variable: exports
NativeScript / 12.1 (12.1; iPhone): Executed 1 of null (1 FAILED) ERROR (0.008 secs / 0 secs)

[NickIliev]

@ochemerys it is possible that the assert from chai is clashing with other TypeScript declared variables.

Try craete a custom config file and remove the import { assert } from 'chai' the following:

import * as chai from "chai";
export const assert: typeof chai.assert = (<any>global).chai.assert;

like done here

[ochemerys]

Thank you for your response,
I was able to run test without import statement

describe('Array', function () {
describe('#indexOf()', function () {
it('should return -1 when the value is not present', function () {
chai.assert.equal(-1, [1,2,3].indexOf(5));
chai.assert.equal(-1, [1,2,3].indexOf(0));
});
});
});

but when I added there import statement:
import { AppComponent } from '../app/app.component'

test fails again with the same error.

so for me problem is not chai, but import statement itself
Does it mean that I have declare every module as global?

Thank you.

[NickIliev]

No need to import all modules as global ones - only the assert from chai is enough.

[ochemerys]

Sorry I was out of my place and was not able to test. I followed your instructions and still have the same issue:
8 11 2018 20:41:32.441:WARN [NativeScript / 12.1 (12.1; iPhone)]: Adapter did not report total number of specs.
CONSOLE LOG file:///app/tns_modules/nativescript-unit-test-runner/main-view-model.js:254:20: NSUTR: completed test run.
NativeScript / 12.1 (12.1; iPhone) /base/src/tests/example.spec.js?4166a63b8fa14f25cec0cebae16daf46c08e4115 at line 0 FAILED
ReferenceError: Can't find variable: exports
NativeScript / 12.1 (12.1; iPhone): Executed 1 of null (1 FAILED) ERROR (0.005 secs / 0 secs)

[ochemerys]

It is very easy to reproduce:

tns create ng-mocha-testdemo --ng
cd ng-mocha-testdemo
npm install
tns test init (and select mocha)
npm i @types/mocha --save-dev

go to tests folder
add test-config.ts with the content you provided
rename existing example.js into example.ts
add first line to example.ts
import { assert } from './test-config';

then run test

tns test ios

[ochemerys]

I think the problem is in a new angular project structure
In my project with old structure tests work perfectly well, but when I generated a new structure , tests ends with posted above error.
new generated project structure structure

Thank you.

[ochemerys]

temporary workaround is here