ci: add tests coverage

.github/codecov.yml

@@ -0,0 +1,17 @@
+github_checks:
+  annotations: true
+
+codecov:
+  require_ci_to_pass: yes
+
+coverage:
+  precision: 2
+  round: down
+  range: 65...100
+
+  status:
+    # Learn more at https://docs.codecov.io/docs/commit-status
+    project:
+      default:
+        target: 65%
+        threshold: 0.05 # allow this much decrease on project

.github/workflows/tests-coverage.yml

@@ -0,0 +1,21 @@
+name: Tests coverage
+
+on: pull_request
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - name: Setup Node.js 14.x
+        uses: actions/setup-node@v2
+        with:
+          node-version: 14.x
+      - name: Install and test
+        run: |
+          yarn --frozen-lockfile
+          yarn test:app --coverage
+      - name: Test Coverage
+        uses: codecov/codecov-action@v3
+        with:
+          fail_ci_if_error: true