fix: harden scan edge cases

core/host_excludes_test.go

@@ -0,0 +1,29 @@
+package core
+
+import (
+	"os"
+	"reflect"
+	"testing"
+
+	"github.com/shadow1ng/fscan/common"
+)
+
+func TestLoadHostExcludesIncludesExcludeFile(t *testing.T) {
+	path := t.TempDir() + "/exclude.txt"
+	if err := os.WriteFile(path, []byte("192.168.1.2\n# comment\n192.168.1.3\n"), 0o600); err != nil {
+		t.Fatalf("WriteFile error = %v", err)
+	}
+
+	got, err := loadHostExcludes(&common.FlagVars{
+		ExcludeHosts:     "192.168.1.1",
+		ExcludeHostsFile: path,
+	})
+	if err != nil {
+		t.Fatalf("loadHostExcludes error = %v", err)
+	}
+
+	want := []string{"192.168.1.1", "192.168.1.2", "192.168.1.3"}
+	if !reflect.DeepEqual(got, want) {
+		t.Fatalf("loadHostExcludes = %#v, want %#v", got, want)
+	}
+}