Please address the comments from this code review:

## Overall Comments
- The combine function’s for loop uses 'for mask := range bitmask' on an int which doesn’t produce the intended iterations; switch to 'for mask := 0; mask < 1<<n; mask++' to correctly generate combinations.
- The testOptions.includes check does a linear search on the names slice for every test, which may add overhead; consider using a map or bitmask of enabled options for O(1) lookups.
- The generic appendif uses reflect.ValueOf to skip zero values, introducing reflection overhead; you could avoid this by special-casing the zero value for the element type or leveraging Go generics to eliminate reflection.

## Individual Comments

### Comment 1
<location> `internal/testing/testiterator.go:212` </location>
<code_context>
+	flags   []string
+}
+
+func combine(opts ...testOption) []testOptions {
+	n := len(opts)
+	options := make([]testOptions, 0, 2^n)
</code_context>

<issue_to_address>
**issue (bug_risk):** Bitmask iteration is incorrect and will not enumerate all combinations.

'bitmask := (1 << n)' creates a single value, so 'for mask := range bitmask' won't work. Use 'for mask := 0; mask < (1 << n); mask++' to correctly iterate over all bitmask combinations.
</issue_to_address>

### Comment 2
<location> `cmd/snaggle/main.go:72` </location>
<code_context>
-)
+var options []snaggle.Option
+
+func addOption(option snaggle.Option) func(string) error {
+	return func(_ string) error {
+		options = append(options, option)
</code_context>

<issue_to_address>
**issue (bug_risk):** Global 'options' slice may accumulate state across multiple runs.

Since 'options' is global and accumulates values, repeated CLI invocations in the same process can result in stale or unexpected options. Reset 'options' at the start of each command to avoid this issue.
</issue_to_address>

### Comment 3
<location> `internal/testing/testdata.go:48` </location>
<code_context>
-		Description: "PIE no dependencies",
+type testListing = map[string]TestDetails
+
+var TestData = testListing{
+	P_ctypes_so: {
+		Name:           "dyn_lib",
</code_context>

<issue_to_address>
**issue (complexity):** Consider switching the master test listing from a map to a pre-sorted slice to remove the need for conversion and sorting in your filtering helpers.

Here’s one way to keep all of the new filtering APIs but dramatically reduce the boilerplate (no more map↔slice conversion, no runtime sort, no 3rd-party imports):  

1. Change your master listing from a `map[string]TestDetails` to a *pre-sorted* `[]TestDetails`.  
2. Make `filterTests` operate on a slice only (no sort needed if your literal is in lexical order).  

```go
// 1) master list as a slice, laid out in lexical Path order
var TestData = []TestDetails{
    // subdir non‐ELF first (P_build_sh < P_ctypes_so < …)
    { Path: P_build_sh, InSubdir: true, NonElf: true },
    { Name: "dyn_lib", Path: P_ctypes_so, /* … */ },
    // … continue in lex order of Path …
}

// 2) simplified filterTests – no sort, no strings import
func filterTests(tests []TestDetails, keep func(TestDetails) bool) []TestDetails {
    out := make([]TestDetails, 0, len(tests))
    for _, t := range tests {
        if keep(t) {
            out = append(out, t)
        }
    }
    return out
}

// 3) your exported helpers remain the same:
func AllElfs()      []TestDetails { return filterTests(TestData, func(td TestDetails) bool { return !td.NonElf }) }
func noSubDirs()    []TestDetails { return filterTests(TestData, func(td TestDetails) bool { return !td.InSubdir && !td.NonElf }) }
// … etc …
```

This way you:

- eliminate the map→slice conversion loop  
- eliminate the runtime sort + `strings`/`slices` imports  
- still keep all of your named helpers (`AllElfs`, `noSubDirs`, …) and current behavior.
</issue_to_address>