Update README.md

README.md

@@ -6,3 +6,51 @@
 [![npm bundle size (scoped version)](https://img.shields.io/bundlephobia/minzip/@uniswap/sdk/latest.svg)](https://bundlephobia.com/result?p=@uniswap/sdk@latest)
 
 In-depth documentation on this SDK is available at [uniswap.org](https://uniswap.org/docs/v2/SDK/getting-started/).
+
+## Running tests
+
+To run the tests, follow these steps. You must have at least node v10 and [yarn](https://yarnpkg.com/) installed.
+
+First clone the repository:
+
+```sh
+git clone https://github.com/Uniswap/uniswap-sdk.git
+```
+
+Move into the uniswap-sdk working directory
+
+```sh
+cd uniswap-sdk/
+```
+
+Install dependencies
+
+```sh
+yarn install
+```
+
+Run tests
+
+```sh
+yarn test
+```
+
+You should see output like the following:
+
+```sh
+yarn run v1.22.4
+$ tsdx test
+ PASS  test/constants.test.ts
+ PASS  test/pair.test.ts
+ PASS  test/fraction.test.ts
+ PASS  test/miscellaneous.test.ts
+ PASS  test/entities.test.ts
+ PASS  test/trade.test.ts
+
+Test Suites: 1 skipped, 6 passed, 6 of 7 total
+Tests:       3 skipped, 82 passed, 85 total
+Snapshots:   0 total
+Time:        5.091s
+Ran all test suites.
+✨  Done in 6.61s.
+```