refactor: extract `seek_end_of_options` into utils and add test helpers

Deduplicate the `seek_end_of_options` function by moving it from both
`arg_matcher` and `flag_matcher` into a single shared implementation in
utils. Add `make_masked` and `make_args` test helpers to the test crate

3 files changed, 16 insertions, 44 deletions

diff --git a/mingling_picker/src/parselib/arg_matcher.rs b/mingling_picker/src/parselib/arg_matcher.rs
index 931652a..808e4a2 100644
--- a/mingling_picker/src/parselib/arg_matcher.rs
+++ b/mingling_picker/src/parselib/arg_matcher.rs
@@ -1,4 +1,7 @@
-use crate::{matcher_needed::*, parselib::build_possible_flags};
+use crate::{
+    matcher_needed::*,
+    parselib::{build_possible_flags, seek_end_of_options},
+};
 
 /// `ArgMatcher` is used for parameters that carry a single value.
 ///
@@ -53,7 +56,6 @@ impl Matcher for ArgMatcher {
         arg_info: &PickerArgInfo,
     ) -> Option<usize> {
         if arg_info.positional {
-            // Positional: first available position.
             return args.first().map(|a| a.raw_idx);
         }
 
@@ -61,7 +63,6 @@ impl Matcher for ArgMatcher {
         let end = seek_end_of_options(args, style);
 
         for arg in args {
-            // Stop at end-of-options marker.
             if end.is_some_and(|e| arg.raw_idx >= e) {
                 break;
             }
@@ -83,7 +84,6 @@ impl Matcher for ArgMatcher {
         arg_info: &PickerArgInfo,
     ) -> Vec<usize> {
         if arg_info.positional {
-            // Positional: all available positions before `--`.
             let end = seek_end_of_options(args, style);
             return args
                 .iter()
@@ -98,7 +98,6 @@ impl Matcher for ArgMatcher {
         let mut result = Vec::new();
         let mut i = 0;
         while i < args.len() {
-            // Stop at end-of-options marker.
             if end.is_some_and(|e| args[i].raw_idx >= e) {
                 break;
             }
@@ -108,28 +107,22 @@ impl Matcher for ArgMatcher {
                 .any(|f| Self::matches(args[i].raw, f, style.case_sensitive));
 
             if matched {
-                // Find which flag matched to check eq mode.
                 let flag_str = possible_flags
                     .iter()
                     .find(|f| Self::matches(args[i].raw, f, style.case_sensitive))
                     .expect("already matched");
 
-                result.push(args[i].raw_idx); // flag position
+                result.push(args[i].raw_idx);
 
                 if !Self::is_eq_mode(args[i].raw, flag_str) {
-                    // Non-eq mode: the next argument is the value.
-                    // Always tag it — even if it looks like a flag — so that
-                    // the mask reserves it. Validation is the Pickable's job.
                     if i + 1 < args.len() {
                         result.push(args[i + 1].raw_idx);
-                        i += 2; // skip flag + value
+                        i += 2;
                         continue;
                     }
-                    // No value available: tag just the flag.
                     i += 1;
                     continue;
                 }
-                // eq mode: value is inline, no extra slot.
                 i += 1;
                 continue;
             }
@@ -139,16 +132,3 @@ impl Matcher for ArgMatcher {
         result
     }
 }
-
-/// Locate the end-of-options marker (`--`) in the argument list.
-fn seek_end_of_options(args: &[MaskedArg], style: &ParserStyle) -> Option<usize> {
-    args.iter()
-        .find(|arg| {
-            if style.case_sensitive {
-                arg.raw == style.end_of_options
-            } else {
-                arg.raw.eq_ignore_ascii_case(style.end_of_options)
-            }
-        })
-        .map(|arg| arg.raw_idx)
-}
diff --git a/mingling_picker/src/parselib/flag_matcher.rs b/mingling_picker/src/parselib/flag_matcher.rs
index 782d0f8..e93d35a 100644
--- a/mingling_picker/src/parselib/flag_matcher.rs
+++ b/mingling_picker/src/parselib/flag_matcher.rs
@@ -1,6 +1,6 @@
 use crate::{
     matcher_needed::*,
-    parselib::{build_possible_flags, get_seeked_first, multi_seek_eq},
+    parselib::{build_possible_flags, get_seeked_first, multi_seek_eq, seek_end_of_options},
 };
 
 /// `FlagMatcher` is used to match flags in command-line arguments.
@@ -80,19 +80,3 @@ fn single_pass_match_all(
 
     matches
 }
-
-/// Locate the end-of-options marker (`--`) in the argument list.
-fn seek_end_of_options(args: &[MaskedArg], style: &ParserStyle) -> Option<usize> {
-    get_seeked_first(
-        args.iter()
-            .filter(|arg| {
-                if style.case_sensitive {
-                    arg.raw == style.end_of_options
-                } else {
-                    arg.raw.eq_ignore_ascii_case(style.end_of_options)
-                }
-            })
-            .map(|arg| arg.raw_idx)
-            .collect(),
-    )
-}
diff --git a/mingling_picker/src/parselib/utils.rs b/mingling_picker/src/parselib/utils.rs
index 5219b02..ae3c203 100644
--- a/mingling_picker/src/parselib/utils.rs
+++ b/mingling_picker/src/parselib/utils.rs
@@ -34,7 +34,15 @@ pub fn build_possible_flags(style: &ParserStyle, arg_info: &PickerArgInfo) -> Ve
 /// subsequent arguments should be treated as positional arguments, not flags.
 #[must_use]
 pub fn seek_end_of_options(args: &[MaskedArg], style: &ParserStyle) -> Option<usize> {
-    get_seeked_first(seek_eq(args, style.end_of_options, style.case_sensitive))
+    args.iter()
+        .find(|arg| {
+            if style.case_sensitive {
+                arg.raw == style.end_of_options
+            } else {
+                arg.raw.eq_ignore_ascii_case(style.end_of_options)
+            }
+        })
+        .map(|arg| arg.raw_idx)
 }
 
 /// Seeks arguments in `args` that are exactly equal to the given `string`.