diff --git a/RFCs/0079-qtest-tap-output.md b/RFCs/0079-qtest-tap-output.md
index af86be9..b7b8244 100644
--- a/RFCs/0079-qtest-tap-output.md
+++ b/RFCs/0079-qtest-tap-output.md
@@ -9,7 +9,7 @@
 
 ## CLI 契约
 
-`qtest --tap FILE_OR_DIRECTORY...` 输出 TAP version 13。输入文件先按现有递归路径排序，然后每个文件恰输出一条编号记录：成功为 `ok N - path`，失败为 `not ok N - path`。失败详情紧随其后按 `# ` 注释行输出；详情中的换行分割为多条注释，避免伪造新的测试记录。末尾输出 `1..N`，其中 `N` 是发现的测试文件数。
+`qtest --tap FILE_OR_DIRECTORY...` 输出 TAP version 13。所有输入递归发现的文件合并后按路径全局排序并去重，然后每个文件恰输出一条编号记录：成功为 `ok N - path`，失败为 `not ok N - path`。失败详情紧随其后按 `# ` 注释行输出；详情中的换行分割为多条注释，避免伪造新的测试记录。末尾输出 `1..N`，其中 `N` 是去重后发现的测试文件数。
 
 `--tap` 与 `--json` 互斥，冲突以用法错误退出码 2 结束。读取错误或找不到测试文件时，在已输出 TAP 版本后输出 `Bail out!` 并以非零状态退出。测试失败仍返回非零状态；`--stats` 继续只写标准错误，不污染 TAP 标准输出。
 
diff --git a/src/bin/qtest.rs b/src/bin/qtest.rs
index 2fcd7e0..af60be0 100644
--- a/src/bin/qtest.rs
+++ b/src/bin/qtest.rs
@@ -112,6 +112,8 @@ fn main() -> ExitCode {
             return ExitCode::from(1);
         }
     }
+    files.sort();
+    files.dedup();
     if files.is_empty() {
         if tap {
             println!("TAP version 13");
diff --git a/src/vm.rs b/src/vm.rs
index 106598a..52fa71a 100644
--- a/src/vm.rs
+++ b/src/vm.rs
@@ -870,23 +870,21 @@ impl Vm {
                                 });
                             }
                             Value::String(value) => {
-                                let values: Rc<Vec<Value>> = Rc::new(
-                                    value
-                                        .chars()
-                                        .map(|character| {
-                                            Value::String(Rc::from(character.to_string()))
-                                        })
-                                        .collect(),
-                                );
-                                let position = if step < 0 {
-                                    values.len().saturating_sub(1)
-                                } else {
-                                    0
-                                };
                                 frame.iterators.push(Iteration {
                                     kind: IterationKind::String {
-                                        values,
-                                        position,
+                                        values: Rc::new(
+                                            value
+                                                .chars()
+                                                .map(|character| {
+                                                    Value::String(Rc::from(character.to_string()))
+                                                })
+                                                .collect(),
+                                        ),
+                                        position: if step < 0 {
+                                            value.chars().count().saturating_sub(1)
+                                        } else {
+                                            0
+                                        },
                                         step,
                                     },
                                 });
diff --git a/tests/cli_tools.rs b/tests/cli_tools.rs
index 72cfc90..e788cb3 100644
--- a/tests/cli_tools.rs
+++ b/tests/cli_tools.rs
@@ -189,9 +189,54 @@ fn qtest_tap_output_is_deterministic_and_describes_failures() {
     assert_eq!(
         String::from_utf8_lossy(&output.stdout),
         format!(
-            "TAP version 13\nnot ok 1 - {}/a-fail.qc\n# final value was 1, expected true\nok 2 - {}/b-pass.qc\n1..2\n",
-            temp.display(),
-            temp.display()
+            "TAP version 13\nnot ok 1 - {}\n# final value was 1, expected true\nok 2 - {}\n1..2\n",
+            temp.join("a-fail.qc").display(),
+            temp.join("b-pass.qc").display()
+        )
+    );
+    let reversed = Command::new(bin("qtest"))
+        .args([
+            "--tap",
+            temp.join("b-pass.qc").to_str().unwrap(),
+            temp.join("a-fail.qc").to_str().unwrap(),
+            temp.join("a-fail.qc").to_str().unwrap(),
+        ])
+        .output()
+        .unwrap();
+    assert!(!reversed.status.success());
+    assert_eq!(
+        String::from_utf8_lossy(&reversed.stdout),
+        format!(
+            "TAP version 13\nnot ok 1 - {}\n# final value was 1, expected true\nok 2 - {}\n1..2\n",
+            temp.join("a-fail.qc").display(),
+            temp.join("b-pass.qc").display()
+        )
+    );
+    let reversed_json = Command::new(bin("qtest"))
+        .args([
+            "--json",
+            temp.join("b-pass.qc").to_str().unwrap(),
+            temp.join("a-fail.qc").to_str().unwrap(),
+            temp.join("a-fail.qc").to_str().unwrap(),
+        ])
+        .output()
+        .unwrap();
+    assert!(!reversed_json.status.success());
+    let failed_path = temp
+        .join("a-fail.qc")
+        .display()
+        .to_string()
+        .replace('\\', "\\\\");
+    let passed_path = temp
+        .join("b-pass.qc")
+        .display()
+        .to_string()
+        .replace('\\', "\\\\");
+    assert_eq!(
+        String::from_utf8_lossy(&reversed_json.stdout),
+        format!(
+            "{{\"ok\":false,\"file\":\"{}\",\"error\":\"final value was 1, expected true\"}}\n{{\"ok\":true,\"file\":\"{}\"}}\n",
+            failed_path, passed_path
         )
     );
     let conflict = Command::new(bin("qtest"))