fix: upload part tmp+rename (B4), transactional last-admin DeleteUser (B5), RowsAffected order (B13)

backend/internal/store/store_test.go

@@ -2,6 +2,7 @@ package store
 
 import (
 	"context"
+	"errors"
 	"os"
 	"testing"
 
@@ -129,3 +130,50 @@ func TestProgressUpsertAndJoin(t *testing.T) {
 		t.Fatalf("views %+v", views)
 	}
 }
+
+func TestDeleteUserLastAdmin(t *testing.T) {
+	s := setup(t)
+	ctx := context.Background()
+	id, err := s.CreateUser(ctx, "onlyadmin", "hash", "admin")
+	if err != nil {
+		t.Fatal(err)
+	}
+	err = s.DeleteUser(ctx, id)
+	if !errors.Is(err, ErrLastAdmin) {
+		t.Fatalf("expected ErrLastAdmin, got %v", err)
+	}
+	// Verify user still exists.
+	_, err = s.GetUserByID(ctx, id)
+	if err != nil {
+		t.Fatal("admin should still exist after blocked delete")
+	}
+}
+
+func TestDeleteUserNonLastAdmin(t *testing.T) {
+	s := setup(t)
+	ctx := context.Background()
+	id1, _ := s.CreateUser(ctx, "admin1", "h", "admin")
+	_, _ = s.CreateUser(ctx, "admin2", "h", "admin")
+	if err := s.DeleteUser(ctx, id1); err != nil {
+		t.Fatalf("should allow deleting non-last admin: %v", err)
+	}
+}
+
+func TestDeleteUserMember(t *testing.T) {
+	s := setup(t)
+	ctx := context.Background()
+	id, _ := s.CreateUser(ctx, "member", "h", "member")
+	if err := s.DeleteUser(ctx, id); err != nil {
+		t.Fatalf("member delete should succeed: %v", err)
+	}
+}
+
+func TestIsUniqueViolation(t *testing.T) {
+	s := setup(t)
+	ctx := context.Background()
+	_, _ = s.CreateUser(ctx, "dup", "h", "member")
+	_, err := s.CreateUser(ctx, "dup", "h", "member")
+	if !IsUniqueViolation(err) {
+		t.Fatalf("expected unique violation, got %v", err)
+	}
+}