Add documentation about environment variables

README.md

@@ -79,6 +79,18 @@ yarn run lint
 
 ### Test
 
+Disable API tests OR define all required etherscan API keys.
+
+```bash
+export DISABLE_API_TESTS=1
+# OR
+export EXPLORER_API_KEY_MAINNET=
+export EXPLORER_API_KEY_RINKEBY=
+export EXPLORER_API_KEY_FUSE=
+export EXPLORER_API_KEY_MATIC=
+export EXPLORER_API_KEY_FANTOM=
+```
+
 Test all the packages in the monorepo.
 
 ```bash

packages/payment-detection/README.md

@@ -64,3 +64,22 @@ The code generation is included in the pre-build script and can be run manually:
 ```
 yarn codegen
 ```
+
+# Test
+
+The `Multichain` `InfoRetriever` tests require etherscan API keys.
+
+Before running the payment-detection tests, disable API tests OR define all
+required etherscan API keys.
+
+```bash
+export DISABLE_API_TESTS=1
+# OR
+export EXPLORER_API_KEY_MAINNET=
+export EXPLORER_API_KEY_RINKEBY=
+export EXPLORER_API_KEY_FUSE=
+export EXPLORER_API_KEY_MATIC=
+export EXPLORER_API_KEY_FANTOM=
+
+yarn run test
+```