#18: implement SMTP Submission (587/465), SASL PLAIN/LOGIN auth and preflight diagnostics

services/protocols/internal/presentation/smtp/sasl_login_test.go

@@ -0,0 +1,67 @@
+package smtppresentation
+
+import (
+	"errors"
+	"testing"
+)
+
+// The LOGIN exchange prompts for the username, then the password, and only
+// then authenticates.
+func TestLoginServer_PromptsThenAuthenticates(t *testing.T) {
+	var gotUser, gotPass string
+	server := newLoginServer(func(username, password string) error {
+		gotUser, gotPass = username, password
+		return nil
+	})
+
+	challenge, done, err := server.Next(nil)
+	if err != nil || done || string(challenge) != "Username:" {
+		t.Fatalf("first step: challenge=%q done=%v err=%v", challenge, done, err)
+	}
+
+	challenge, done, err = server.Next([]byte("user@example.test"))
+	if err != nil || done || string(challenge) != "Password:" {
+		t.Fatalf("second step: challenge=%q done=%v err=%v", challenge, done, err)
+	}
+
+	_, done, err = server.Next([]byte("secret"))
+	if err != nil || !done {
+		t.Fatalf("third step: done=%v err=%v", done, err)
+	}
+	if gotUser != "user@example.test" || gotPass != "secret" {
+		t.Errorf("credentials = %q/%q", gotUser, gotPass)
+	}
+}
+
+// A client that sends the username as its initial response skips the first
+// prompt.
+func TestLoginServer_AcceptsInitialResponse(t *testing.T) {
+	server := newLoginServer(func(string, string) error { return nil })
+
+	challenge, done, err := server.Next([]byte("user@example.test"))
+	if err != nil || done || string(challenge) != "Password:" {
+		t.Fatalf("challenge=%q done=%v err=%v", challenge, done, err)
+	}
+}
+
+func TestLoginServer_PropagatesAuthFailure(t *testing.T) {
+	authErr := errors.New("bad credentials")
+	server := newLoginServer(func(string, string) error { return authErr })
+
+	server.Next(nil)
+	server.Next([]byte("user@example.test"))
+	if _, done, err := server.Next([]byte("wrong")); err == nil || done {
+		t.Fatalf("expected the failure to surface: done=%v err=%v", done, err)
+	}
+}
+
+func TestLoginServer_RefusesExtraSteps(t *testing.T) {
+	server := newLoginServer(func(string, string) error { return nil })
+	server.Next(nil)
+	server.Next([]byte("user@example.test"))
+	server.Next([]byte("secret"))
+
+	if _, _, err := server.Next([]byte("extra")); err == nil {
+		t.Fatal("expected an error after the exchange finished")
+	}
+}