Angular 4 Karma Unit Testing, not detecting the tests - angularjs

Question

I am trying to introduce unit testing to my Angular 4 project. I am using Karma for it. I have done the configuration. It shows a connected screen. But it shows not tests! I have one test under src/app/ directory.
This error appears in console.
{
"originalErr": {
"__zone_symbol__currentTask": {
"type": "microTask",
"state": "notScheduled",
"source": "Promise.then",
"zone": "<root>",
"cancelFn": null,
"runCount": 0
}
},
"__zone_symbol__currentTask": {
"type": "microTask",
"state": "notScheduled",
"source": "Promise.then",
"zone": "<root>",
"cancelFn": null,
"runCount": 0
}
}
1st.spec.ts
describe('1st tests', () => {
it('true is true', () => expect(true).toBe(true));
});
karma.config.js
module.exports = function(config) {
var appBase = 'src/'; // transpiled app JS and map files
var appAssets = '/base/app/'; // component assets fetched by Angular's compiler
// Testing helpers (optional) are conventionally in a folder called `testing`
var testingBase = 'src/testing/'; // transpiled test JS and map files
var testingSrcBase = 'src/testing/'; // test source TS files
config.set({
basePath: '',
frameworks: ['jasmine'],
plugins: [
require('karma-jasmine'),
require('karma-chrome-launcher'),
require('karma-jasmine-html-reporter')
],
client: {
builtPaths: [appBase, testingBase], // add more spec base paths as needed
clearContext: false // leave Jasmine Spec Runner output visible in browser
},
customLaunchers: {
// From the CLI. Not used here but interesting
// chrome setup for travis CI using chromium
Chrome_travis_ci: {
base: 'Chrome',
flags: ['--no-sandbox']
}
},
files: [
// System.js for module loading
'node_modules/systemjs/dist/system.src.js',
// Polyfills
'node_modules/core-js/client/shim.js',
// zone.js
'node_modules/zone.js/dist/zone.js',
'node_modules/zone.js/dist/long-stack-trace-zone.js',
'node_modules/zone.js/dist/proxy.js',
'node_modules/zone.js/dist/sync-test.js',
'node_modules/zone.js/dist/jasmine-patch.js',
'node_modules/zone.js/dist/async-test.js',
'node_modules/zone.js/dist/fake-async-test.js',
// RxJs
{ pattern: 'node_modules/rxjs/**/*.js', included: false, watched: false },
{ pattern: 'node_modules/rxjs/**/*.js.map', included: false, watched: false },
// Paths loaded via module imports:
// Angular itself
{ pattern: 'node_modules/#angular/**/*.js', included: false, watched: false },
{ pattern: 'node_modules/#angular/**/*.js.map', included: false, watched: false },
{ pattern: appBase + '/systemjs.config.js', included: false, watched: false },
{ pattern: appBase + '/systemjs.config.extras.js', included: false, watched: false },
'karma-test-shim.js', // optionally extend SystemJS mapping e.g., with barrels
// transpiled application & spec code paths loaded via module imports
{ pattern: appBase + '**/*.js', included: false, watched: true },
{ pattern: testingBase + '**/*.js', included: false, watched: true },
// Asset (HTML & CSS) paths loaded via Angular's component compiler
// (these paths need to be rewritten, see proxies section)
{ pattern: appBase + '**/*.html', included: false, watched: true },
{ pattern: appBase + '**/*.css', included: false, watched: true },
// Paths for debugging with source maps in dev tools
{ pattern: appBase + '**/*.ts', included: false, watched: false },
{ pattern: appBase + '**/*.js.map', included: false, watched: false },
{ pattern: testingSrcBase + '**/*.ts', included: false, watched: false },
{ pattern: testingBase + '**/*.js.map', included: false, watched: false}
],
// Proxied base paths for loading assets
proxies: {
// required for modules fetched by SystemJS
'/base/src/node_modules/': '/base/node_modules/'
},
exclude: [],
preprocessors: {},
reporters: ['progress', 'kjhtml'],
port: 9876,
colors: true,
logLevel: config.LOG_INFO,
autoWatch: true,
browsers: ['Chrome'],
singleRun: false
})
}
Karma Connection Screen:
Any lead to help, will be helpful.