Introduce basic js unit tests

Signed-off-by: Thomas Citharel <tcit@tcit.fr>

js/package.json

@@ -5,7 +5,7 @@
   "scripts": {
     "serve": "vue-cli-service serve",
     "build": "vue-cli-service build --modern",
-    "test:unit": "vue-cli-service test:unit",
+    "test:unit": "LANG=en_US.UTF-8 LANGUAGE=en_US:en LC_ALL=en_US.UTF-8 vue-cli-service test:unit",
     "test:e2e": "vue-cli-service test:e2e",
     "lint": "vue-cli-service lint"
   },
@@ -39,6 +39,7 @@
     "tippy.js": "^6.2.3",
     "tiptap": "^1.26.0",
     "tiptap-extensions": "^1.29.1",
+    "unfetch": "^4.2.0",
     "v-tooltip": "2.0.2",
     "vue": "^2.6.11",
     "vue-apollo": "^3.0.3",
@@ -52,6 +53,7 @@
     "vuedraggable": "2.23.2"
   },
   "devDependencies": {
+    "@types/jest": "^24.0.19",
     "@types/leaflet": "^1.5.2",
     "@types/leaflet.locatecontrol": "^0.60.7",
     "@types/lodash": "^4.14.141",
@@ -69,6 +71,7 @@
     "@vue/cli-plugin-pwa": "~4.5.9",
     "@vue/cli-plugin-router": "~4.5.9",
     "@vue/cli-plugin-typescript": "~4.5.9",
+    "@vue/cli-plugin-unit-jest": "~4.5.0",
     "@vue/cli-service": "~4.5.9",
     "@vue/eslint-config-airbnb": "^5.0.2",
     "@vue/eslint-config-prettier": "^6.0.0",
@@ -79,6 +82,7 @@
     "eslint-plugin-import": "^2.20.2",
     "eslint-plugin-prettier": "^3.1.3",
     "eslint-plugin-vue": "^7.0.0",
+    "mock-apollo-client": "^0.4",
     "prettier": "2.2.1",
     "prettier-eslint": "^12.0.0",
     "sass": "^1.29.0",