docs(README): document extra args

README.md

@@ -32,23 +32,31 @@ use({
 
 _NOTE_: all usages of `require('neotest').run.run` can be mapped to a command in your config (this is not included and should be done by the user)
 
-### Test single function
+#### Test single function
 
 To test a single test hover over the test and run `require('neotest').run.run()`
 
-### Test File
+#### Test file
 
 To test a file run `require('neotest').run.run(vim.fn.expand('%'))`
 
-### Test Directory
+#### Test directory
 
 To test a directory run `require('neotest').run.run("path/to/directory")`
 
-### Test Suite
+#### Test suite
 
 To test the full test suite run `require('neotest').run.run("path/to/root_project")`
 e.g. `require('neotest').run.run(vim.fn.getcwd())`, presuming that vim's directory is the same as the project root
 
+#### Additional arguments
+
+Additional arguments for the go test command can be sent using the `extra_args` field e.g.
+
+```lua
+require('neotest').run.run({path, extra_args = {"-race"}})
+```
+
 ## Contributing
 
 This project is maintained by the nvim golang community. Please raise a PR if you are interested in adding new functionality or fixing any bugs