diff --git a/internal/cli/app.go b/internal/cli/app.go
index 21a5e1e..0b58d50 100644
--- a/internal/cli/app.go
+++ b/internal/cli/app.go
@@ -10,7 +10,7 @@ type App struct {
 	store secretstore.Store
 }
 
-func NewApp(_ ...any) *App {
+func NewApp() *App {
 	return &App{}
 }
 
diff --git a/internal/cli/app_test.go b/internal/cli/app_test.go
index 3af3df8..19b263a 100644
--- a/internal/cli/app_test.go
+++ b/internal/cli/app_test.go
@@ -5,6 +5,8 @@ import (
 	"testing"
 )
 
+var _ func() *App = NewApp
+
 func TestAppRunRejectsUnknownCommand(t *testing.T) {
 	app := NewApp()
 
diff --git a/internal/secretstore/store_test.go b/internal/secretstore/store_test.go
index 4ac06df..0ffc95d 100644
--- a/internal/secretstore/store_test.go
+++ b/internal/secretstore/store_test.go
@@ -3,9 +3,33 @@ package secretstore
 import "testing"
 
 func TestCredentialValidateRequiresAllFields(t *testing.T) {
-	cred := Credential{Host: "imap.example.com", Username: "alice"}
+	tests := []struct {
+		name string
+		cred Credential
+	}{
+		{
+			name: "missing host",
+			cred: Credential{Username: "alice", Password: "secret"},
+		},
+		{
+			name: "missing username",
+			cred: Credential{Host: "imap.example.com", Password: "secret"},
+		},
+		{
+			name: "missing password",
+			cred: Credential{Host: "imap.example.com", Username: "alice"},
+		},
+		{
+			name: "whitespace only fields",
+			cred: Credential{Host: " \t ", Username: "\n", Password: "   "},
+		},
+	}
 
-	if err := cred.Validate(); err == nil {
-		t.Fatal("expected validation error when password is missing")
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if err := tt.cred.Validate(); err == nil {
+				t.Fatal("expected validation error when a required field is missing")
+			}
+		})
 	}
 }