Update functional tests documentation

x-pack/plugins/apm/readme.md

@@ -80,19 +80,38 @@ For debugging access Elasticsearch on http://localhost:9220` (elastic/changeme)
 
 ### API integration tests
 
+Our tests are separated in two suites: one suite runs with a basic license, and the other
+with a trial license (the equivalent of gold+). This requires separate test servers and test runs.
+
 **Start server**
 
+Basic:
+
+```
+node scripts/functional_tests_server --config x-pack/test/apm_api_integration/basic/config.ts
+```
+
+Trial:
+
 ```
-node scripts/functional_tests_server --config x-pack/test/api_integration/config.ts
+node scripts/functional_tests_server --config x-pack/test/apm_api_integration/trial/config.ts
 ```
 
 **Run tests**
 
+Basic:
+
+```
+node scripts/functional_test_runner --config x-pack/test/apm_api_integration/basic/config.ts
+```
+
+Trial:
+
 ```
-node scripts/functional_test_runner --config x-pack/test/api_integration/config.ts --grep='APM specs'
+node scripts/functional_test_runner --config x-pack/test/apm_api_integration/trial/config.ts
 ```
 
-APM tests are located in `x-pack/test/api_integration/apis/apm`.
+APM tests are located in `x-pack/test/apm_api_integration`.
 For debugging access Elasticsearch on http://localhost:9220` (elastic/changeme)
 
 ### Linting