Started adding tests

config/parser.go

@@ -66,18 +66,12 @@ func (p *parser) err(kind, msg string) error {
 }
 
 // parseAddress takes a host:port string (val), and returns the host
-// and port as separate values. If either value that is missing, the
-// default will be used.4
-func (p *parser) parseAddress(val string) (string, string) {
-	if val == "" {
-		return defaultHost, defaultPort
-	}
+// and port as separate values. Empty strings can be returned if
+// either is missing.
+func parseAddress(val string) (string, string) {
 	parts := strings.SplitN(val, ":", 3)
-	if parts[0] == "" {
-		parts[0] = defaultHost
-	}
-	if len(parts) == 1 || parts[1] == "" {
-		return parts[0], defaultPort
+	if len(parts) == 1 {
+		return parts[0], ""
 	} else {
 		return parts[0], parts[1]
 	}

config/parsing.go

@@ -23,7 +23,7 @@ func (p *parser) parse() error {
 // address expects that the current token is a host:port
 // combination.
 func (p *parser) address() error {
-	p.cfg.Host, p.cfg.Port = p.parseAddress(p.tkn())
+	p.cfg.Host, p.cfg.Port = parseAddress(p.tkn())
 	p.lexer.Next()
 	return nil
 }

config/parsing_test.go

+package config
+
+import "testing"
+
+func TestParseAddress(t *testing.T) {
+	type addr struct {
+		host string
+		port string
+	}
+	testCases := []struct {
+		input    string
+		expected addr
+	}{
+		{input: "host:port", expected: addr{host: "host", port: "port"}},
+		{input: "localhost:1234", expected: addr{host: "localhost", port: "1234"}},
+		{input: "127.0.0.1:0", expected: addr{host: "127.0.0.1", port: "0"}},
+		{input: "127.0.0.1", expected: addr{host: "127.0.0.1", port: ""}},
+		{input: "somedomain.com", expected: addr{host: "somedomain.com", port: ""}},
+		{input: "somedomain.com:", expected: addr{host: "somedomain.com", port: ""}},
+		{input: ":80", expected: addr{host: "", port: "80"}},
+		{input: "localhost:8080", expected: addr{host: "localhost", port: "8080"}},
+		{input: "", expected: addr{host: "", port: ""}},
+	}
+	for _, test := range testCases {
+		actualHost, actualPort := parseAddress(test.input)
+		if actualHost != test.expected.host {
+			t.Errorf("For '%s' expected host '%s' but got '%s'", test.input, test.expected.host, actualHost)
+		}
+		if actualPort != test.expected.port {
+			t.Errorf("For '%s' expected port '%s' but got '%s'", test.input, test.expected.port, actualPort)
+		}
+	}
+}