Make connections configurable and skippable

It is a hassle to setup all potential connection and authentication
types. And it is impossible to test Unix domain sockets on Windows. Make
testing non-default connections optional.

README.md

@@ -1,25 +1,50 @@
-pgx
-===
+# pgx
 
 Experimental PostgreSQL client library for Go
 
-Usage
-=====
+## Usage
 
 TODO
 
-Development
-===========
+## Development
 
-Testing
--------
+## Testing
 
-To setup the test environment run the test_setup.sql script as a user that can
-create users and databases. To successfully run the connection tests for various
-means of authentication you must include the following in your pg_hba.conf.
+Pgx supports multiple connection and authentication types. Setting up a test
+environment that can test all of them can be cumbersome. In particular,
+Windows cannot test Unix domain socket connections. Because of this pgx will
+skip tests for connection types that are not configured.
+
+### Normal Test Environment
+
+To setup the normal test environment run the following SQL:
+
+    create user pgx_md5 password 'secret';
+    create database pgx_test;
+
+Next open connection_settings_test.go.example and make a copy without the
+.example. If your PostgreSQL server is accepting connections on 127.0.0.1,
+then you are done.
+
+### Connection and Authentication Test Environment
+
+Comple the normal test environment setup and also do the following.
+
+Run the following SQL:
+
+    create user pgx_none;
+    create user pgx_pw password 'secret';
+
+Add the following to your pg_hba.conf:
+
+If you are developing on Unix with domain socket connections:
 
     local  pgx_test  pgx_none  trust
     local  pgx_test  pgx_pw    password
     local  pgx_test  pgx_md5   md5
 
+If you are developing on Windows with TCP connections:
 
+    host  pgx_test  pgx_none  127.0.0.1/32 trust
+    host  pgx_test  pgx_pw    127.0.0.1/32 password
+    host  pgx_test  pgx_md5   127.0.0.1/32 md5