fix: add jest coverage config to package.json (#3896)

* fix: add jest coverage config to package.json

* fix: add running test instructions to CONTRIBUTING.md

* fix: respond to zzmp comments

* fix: lower test thresholds
Co-authored-by: Lynn Yu <lynn.yu@uniswap.org>

CONTRIBUTING.md

-
 # Contributing
 
 Thank you for your interest in contributing to the Uniswap interface! 🦄
@@ -15,10 +14,20 @@ Thank you for your interest in contributing to the Uniswap interface! 🦄
 1. `yarn install`
 1. `yarn build`
 
+## Running unit tests
+
+- Run unit tests: `yarn test`
+- Run unit tests and show test coverage info for all tests: `yarn test --watchAll`
+
+## Running cypress integration tests
+
+1. `yarn build:e2e`
+2. `yarn test:e2e`
+
 ## Engineering standards
 
-Code merged into the `main` branch of this repository should adhere to high standards of correctness and maintainability. 
-Use your best judgment when applying these standards.  If code is in the critical path, will be frequently visited, or 
+Code merged into the `main` branch of this repository should adhere to high standards of correctness and maintainability.
+Use your best judgment when applying these standards. If code is in the critical path, will be frequently visited, or
 makes large architectural changes, consider following all the standards.
 
 - Have at least one engineer approve of large code refactorings
@@ -39,7 +48,7 @@ The following points should help guide your development:
   - Avoid adding steps to the development/build processes
   - The build must be deterministic, i.e. a particular commit hash always produces the same build
 - Decentralization: anyone can run the interface
-  - An Ethereum node should be the only critical dependency 
+  - An Ethereum node should be the only critical dependency
   - All other external dependencies should only enhance the UX ([graceful degradation](https://developer.mozilla.org/en-US/docs/Glossary/Graceful_degradation))
 - Accessibility: anyone can use the interface
   - The interface should be responsive, small and also run well on low performance devices (majority of swaps on mobile!)
@@ -48,14 +57,14 @@ The following points should help guide your development:
 
 Releases are cut automatically from the `main` branch Monday-Thursday in the morning according to the [release workflow](./.github/workflows/release.yaml).
 
-Fix pull requests should be merged whenever ready and tested. 
+Fix pull requests should be merged whenever ready and tested.
 If a fix is urgently needed in production, releases can be manually triggered on [GitHub](https://github.com/Uniswap/uniswap-interface/actions/workflows/release.yaml)
 after the fix is merged into `main`.
 
 Features should not be merged into `main` until they are ready for users.
 When building larger features or collaborating with other developers, create a new branch from `main` to track its development.
 Use the automatic Vercel preview for sharing the feature to collect feedback.  
-When the feature is ready for review, create a new pull request from the feature branch into `main` and request reviews from 
+When the feature is ready for review, create a new pull request from the feature branch into `main` and request reviews from
 the appropriate UX reviewers (PMs or designers).
 
 ## Finding a first issue
@@ -65,7 +74,7 @@ Start with issues with the label
 
 # Translations
 
-Uniswap uses [Crowdin](https://crowdin.com/project/uniswap-interface) for managing translations. 
+Uniswap uses [Crowdin](https://crowdin.com/project/uniswap-interface) for managing translations.
 [This workflow](./.github/workflows/crowdin.yaml) uploads new strings for translation to the Crowdin project whenever code using the [lingui translation macros](https://lingui.js.org/ref/macro.html) is merged into `main`.
 
 Every hour, translations are synced back down from Crowdin to the repository in [this other workflow](./.github/workflows/crowdin-sync.yaml).

package.json

@@ -16,11 +16,32 @@
     "prepare": "yarn contracts:compile && yarn graphql:generate && yarn i18n:compile",
     "start": "react-scripts start",
     "build": "react-scripts build",
-    "test": "react-scripts test",
+    "test": "react-scripts test --coverage",
     "build:e2e": "env-cmd -f .env yarn build",
     "test:e2e": "start-server-and-test 'serve build -l 3000' http://localhost:3000 'cypress open'",
     "test:e2e:ci": "start-server-and-test 'serve build -l 3000' http://localhost:3000 'cypress run --record'"
   },
+  "jest": {
+    "collectCoverageFrom": 
+    [
+      "src/components/**/*.ts*", 
+      "src/hooks/**/*.ts*", 
+      "src/lib/hooks/**/*.ts*", 
+      "src/lib/state/**/*.ts*", 
+      "src/lib/utils/**/*.ts*", 
+      "src/pages/**/*.ts*",
+      "src/state/**/*.ts*",
+      "src/utils/**/*.ts*"
+    ],
+    "coverageThreshold": {
+      "global": {
+        "branches": 4,
+        "functions": 6,
+        "lines": 9,
+        "statements": 9
+      }
+    }
+  },
   "browserslist": {
     "production": [
       ">0.2%",