Add +/- buttons in scale deployment popup screen (#1191)

* Add @testing-library/jest-dom and @testing-library/react for writing test cases

* Make eslint check __mocks__/*.ts files

* Mock electron.ipcRenderer.on to prevent errors in React compoment test cases

* Mock <Trans /> from @lingui/macro as a component simplely returns children components

* Use optional chaining operator (?.) to avoid TypeError: Cannot read property 'replicas' of undefined

* Add jest-fetch-mock for mocking global.fetch, activate for all test cases in jest.setup.ts

* Add basic tests for <DeploymentScaleDialog /> to ensure it initialises/renders without errors

* Add +/- button for changing desired replicas, and its test cases

* Adjust the styles of +/- buttons container to make sure it aligns with the slider

* Refactor after rebase from master

* Use var defined in vars.scss

* Add flex align-center to slider-container and remove margin-top: -4px

* Use <Icon /> to replace <i/>

* Add flex gaps to plus-minus-container

Signed-off-by: Hung-Han (Henry) Chen <1474479+chenhunghan@users.noreply.github.com>

package.json

@@ -71,10 +71,14 @@
       "^.+\\.tsx?$": "ts-jest"
     },
     "moduleNameMapper": {
-      "\\.(css|scss)$": "<rootDir>/__mocks__/styleMock.ts"
+      "\\.(css|scss)$": "<rootDir>/__mocks__/styleMock.ts",
+      "^@lingui/macro$": "<rootDir>/__mocks__/@linguiMacro.ts"
     },
     "modulePathIgnorePatterns": [
       "<rootDir>/dist"
+    ],
+    "setupFiles": [
+      "<rootDir>/src/jest.setup.ts"
     ]
   },
   "build": {
@@ -264,6 +268,8 @@
     "@lingui/react": "^3.0.0-13",
     "@material-ui/core": "^4.10.1",
     "@rollup/plugin-json": "^4.1.0",
+    "@testing-library/jest-dom": "^5.11.5",
+    "@testing-library/react": "^11.1.0",
     "@types/chart.js": "^2.9.21",
     "@types/circular-dependency-plugin": "^5.0.1",
     "@types/color": "^3.0.1",
@@ -337,6 +343,7 @@
     "identity-obj-proxy": "^3.0.0",
     "include-media": "^1.4.9",
     "jest": "^26.0.1",
+    "jest-fetch-mock": "^3.0.3",
     "jest-mock-extended": "^1.0.10",
     "make-plural": "^6.2.1",
     "mini-css-extract-plugin": "^0.9.0",