docs: Document lint tests

Author: Mason Simon

test/README.md

@@ -3,17 +3,18 @@ utilities in their entirety. It does not contain unit tests, which
 can be found in [/src/test](/src/test), [/src/wallet/test](/src/wallet/test),
 etc.
 
-There are currently two sets of tests in this directory:
+This directory contains the following sets of tests:
 
 - [functional](/test/functional) which test the functionality of
 bitcoind and bitcoin-qt by interacting with them through the RPC and P2P
 interfaces.
 - [util](/test/util) which tests the bitcoin utilities, currently only
 bitcoin-tx.
+- [lint](/test/lint/) which perform various static analysis checks.
 
 The util tests are run as part of `make check` target. The functional
-tests are run by the travis continuous build process whenever a pull
-request is opened. Both sets of tests can also be run locally.
+tests and lint scripts are run by the travis continuous build process whenever a pull
+request is opened. All sets of tests can also be run locally.
 
 # Running tests locally
 
@@ -30,7 +31,7 @@ The ZMQ functional test requires a python ZMQ library. To install it:
 
 #### Running the tests
 
-Individual tests can be run by directly calling the test script, eg:
+Individual tests can be run by directly calling the test script, e.g.:
 
 ```
 test/functional/feature_rbf.py
@@ -180,6 +181,26 @@ Note: gdb attach step may require `sudo`
 Util tests can be run locally by running `test/util/bitcoin-util-test.py`.
 Use the `-v` option for verbose output.
 
+### Lint tests
+
+#### Dependencies
+
+The lint tests require codespell and flake8. To install: `pip3 install codespell flake8`.
+
+#### Running the tests
+
+Individual tests can be run by directly calling the test script, e.g.:
+
+```
+test/lint/lint-filenames.sh
+```
+
+You can run all the shell-based lint tests by running:
+
+```
+test/lint/lint-all.sh
+```
+
 # Writing functional tests
 
 You are encouraged to write functional tests for new or existing features.