add tests for charset parameter on live connection

The charset parameter is only tested in the dsn parser.
Add tests on the database connection.
This is currently broken for fallback charsets.

driver_test.go

@@ -12,6 +12,7 @@ import (
 )
 
 var (
+	charset string
 	dsn     string
 	netAddr string
 	run     bool
@@ -43,8 +44,9 @@ func getEnv() bool {
 			dbname = "gotest"
 		}
 
+		charset = "charset=utf8"
 		netAddr = fmt.Sprintf("%s(%s)", prot, addr)
-		dsn = fmt.Sprintf("%s:%s@%s/%s?timeout=30s&charset=utf8", user, pass, netAddr, dbname)
+		dsn = fmt.Sprintf("%s:%s@%s/%s?timeout=30s&"+charset, user, pass, netAddr, dbname)
 
 		c, err := net.Dial(prot, addr)
 		if err == nil {
@@ -78,6 +80,54 @@ func mustQuery(t *testing.T, db *sql.DB, query string, args ...interface{}) (row
 	return
 }
 
+func mustSetCharset(t *testing.T, charsetParam, expected string) {
+	db, err := sql.Open("mysql", strings.Replace(dsn, charset, charsetParam, 1))
+	if err != nil {
+		t.Fatalf("Error connecting: %v", err)
+	}
+
+	rows := mustQuery(t, db, ("SELECT @@character_set_connection"))
+	if !rows.Next() {
+		t.Fatalf("Error getting connection charset: %v", err)
+	}
+
+	var got string
+	rows.Scan(&got)
+
+	if got != expected {
+		t.Fatalf("Expected connection charset %s but got %s", expected, got)
+	}
+	db.Close()
+}
+
+func TestCharset(t *testing.T) {
+	if !getEnv() {
+		t.Logf("MySQL-Server not running on %s. Skipping TestCharset", netAddr)
+		return
+	}
+
+	// non utf8 test
+	mustSetCharset(t, "charset=ascii", "ascii")
+}
+
+func TestFallbackCharset(t *testing.T) {
+	if !getEnv() {
+		t.Logf("MySQL-Server not running on %s. Skipping TestCharsets", netAddr)
+		return
+	}
+
+	// when the first charset is invalid, use the second
+	mustSetCharset(t, "charset=none,utf8", "utf8")
+
+	// when the first charset is valid, use it
+	charsets := []string{"ascii", "utf8"}
+	for i := range charsets {
+		expected := charsets[i]
+		other := charsets[1-i]
+		mustSetCharset(t, "charset="+expected+","+other, expected)
+	}
+}
+
 func TestCRUD(t *testing.T) {
 	if !getEnv() {
 		t.Logf("MySQL-Server not running on %s. Skipping TestCRUD", netAddr)