Minor improvements

README.md

@@ -5,6 +5,7 @@ $ sudo apt install python3-pytest
 $ pip3 install splinter
 $ pip3 install pytest-splinter
 $ pip3 install pytest-bdd
+$ sudo apt install xvfb  # optional, to avoid opening browser windows
 $ pip3 install pytest-xvfb  # optional, to avoid opening browser windows
 ```
 
@@ -31,7 +32,7 @@ the host system at https://localhost:4430/.
 Create a new user as follows:
 
 * Username: tester
-* Password: tester@123
+* Password: testingtesting
 
 This step is optional if a fresh install of Plinth is being
 tested. Plinth-tester will create the required user using Plinth's
@@ -49,3 +50,10 @@ can also specify which tests to run, by tag or keyword:
 ```
 $ py.test -k essential
 ```
+
+If xvfb is installed and you still want to see browser windows, use the 
+`--no-xvfb` command-line argument.
+
+```
+$ py.test --no-xvfb -k mediawiki
+```

config.ini

@@ -1,4 +1,4 @@
 [DEFAULT]
 url = https://localhost:4430
 username = tester
-password = tester
+password = testingtesting