Ui snapshot testing

[akshaymhetre]

Child of #1075

Snapshot based unit testing for UI

[akshaymhetre]

Referred following doc to integrate Jest with angular :
https://medium.com/@nerdic.coder/how-to-use-jest-unit-tests-with-angular-87509b500158

Apart from this, was getting TS:2339 : property 'toMatchSnapshot' does not exist on type Matchers<ComponentFixture>

Resolved this by adding globals diagnosis configuration (also added options which were default for jest-preset-angular)

"jest": {
"preset": "jest-preset-angular",
"setupFilesAfterEnv": [
"/src/setupJest.ts"
],
"globals": {
"ts-jest": {
"tsConfig": "/src/tsconfig.spec.json", // default for jest-preset-angular
"stringifyContentPathRegex": "\.html$", // default for jest-preset-angular
"astTransformers": ["node_modules/jest-preset-angular/InlineHtmlStripStylesTransformer"], // default for jest-preset-angular
"diagnostics": {
"ignoreCodes": ["6059", "18002", "18003", "TS2339"] //apart from TS2339 all were default for jest-preset-angular
}
}
}
},