diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 12a50dd..0d1f726 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -20,35 +20,25 @@ jobs:
           sudo apt-get update
           sudo apt-get install -y cmake ninja-build gcc
 
+      - name: Clean build directory
+        run: |
+          rm -rf build
+
       - name: Configure
         run: |
-          cmake -S . -B build \
-            -G Ninja \
-            -DCMAKE_BUILD_TYPE=Release
+          cmake -S . -B build -G Ninja -DCMAKE_BUILD_TYPE=Release
 
       - name: Build
         run: |
           cmake --build build
 
-      - name: Verify sorted output (correct list)
+          - name: Run correctness + compare to qsort
         run: |
-          ./build/test_all 200000 123 | tee result.txt
-
-          echo "Checking correctness..."
-          if grep -q "sorted: NO" result.txt; then
-            echo "❌ Sorting error detected"
+          TEST_ALL=$(find build -type f -executable -name test_all | head -n 1 || true)
+          if [ -z "$TEST_ALL" ]; then
+            echo "test_all not found"
+            find build -type f
             exit 1
           fi
-
-          if ! grep -q "sorted: YES" result.txt; then
-            echo "❌ No successful sort detected"
-            exit 1
-          fi
-
-          echo "✅ All lists sorted correctly"
-
-      - name: 5M benchmark vs qsort
-        if: github.event_name == 'workflow_dispatch'
-        run: |
-          ./build/bench_u128_qsort 5000000 123
+          "$TEST_ALL" 5000000 123
 
diff --git a/CMakeLists.txt b/CMakeLists.txt
index f36ddbd..2fee842 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -17,6 +17,8 @@ add_library(pipesort_obj OBJECT
 )
 add_executable(bench_u128_qsort tests/bench_u128_qsort.c)
 target_link_libraries(bench_u128_qsort PRIVATE pipesort)
+add_executable(test_all tests/test_all.c)
+target_link_libraries(test_all PRIVATE pipesort)
 
 target_include_directories(pipesort_obj PUBLIC
     ${CMAKE_CURRENT_SOURCE_DIR}/include
diff --git a/tests/test_all.c b/tests/test_all.c
new file mode 100644
index 0000000..dc1b971
--- /dev/null
+++ b/tests/test_all.c
@@ -0,0 +1,111 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <string.h>
+#include <time.h>
+
+#include "../include/pipesort/pipesort.h"  
+
+
+static inline uint64_t xorshift64(uint64_t *s) {
+    uint64_t x = *s;
+    x ^= x << 13;
+    x ^= x >> 7;
+    x ^= x << 17;
+    *s = x;
+    return x;
+}
+
+static double now_sec(void) {
+    struct timespec ts;
+    clock_gettime(CLOCK_MONOTONIC, &ts);
+    return (double)ts.tv_sec + (double)ts.tv_nsec * 1e-9;
+}
+
+static int cmp_u128(const void *a, const void *b) {
+    const psort_u128_t *x = (const psort_u128_t *)a;
+    const psort_u128_t *y = (const psort_u128_t *)b;
+    if (x->hi < y->hi) return -1;
+    if (x->hi > y->hi) return  1;
+    if (x->lo < y->lo) return -1;
+    if (x->lo > y->lo) return  1;
+    return 0;
+}
+
+static int is_sorted_u128(const psort_u128_t *a, int n) {
+    for (int i = 1; i < n; i++) {
+        if (a[i-1].hi > a[i].hi) return 0;
+        if (a[i-1].hi == a[i].hi && a[i-1].lo > a[i].lo) return 0;
+    }
+    return 1;
+}
+
+static int arrays_equal_u128(const psort_u128_t *a, const psort_u128_t *b, int n) {
+    return memcmp(a, b, (size_t)n * sizeof(psort_u128_t)) == 0;
+}
+
+int main(int argc, char **argv) {
+    int n = (argc > 1) ? atoi(argv[1]) : 200000;
+    uint64_t seed = (argc > 2) ? (uint64_t)strtoull(argv[2], NULL, 10) : 123;
+
+    if (n <= 0) {
+        fprintf(stderr, "n must be > 0\n");
+        return 2;
+    }
+
+    printf("test_all: n=%d seed=%llu\n", n, (unsigned long long)seed);
+
+    psort_u128_t *base = (psort_u128_t *)malloc((size_t)n * sizeof(psort_u128_t));
+    psort_u128_t *a_q  = (psort_u128_t *)malloc((size_t)n * sizeof(psort_u128_t));
+    psort_u128_t *a_p  = (psort_u128_t *)malloc((size_t)n * sizeof(psort_u128_t));
+
+    if (!base || !a_q || !a_p) {
+        fprintf(stderr, "malloc failed\n");
+        free(base); free(a_q); free(a_p);
+        return 2;
+    }
+
+    uint64_t s = seed ? seed : 1;
+    for (int i = 0; i < n; i++) {
+        base[i].hi = xorshift64(&s);
+        base[i].lo = xorshift64(&s);
+    }
+
+    memcpy(a_q, base, (size_t)n * sizeof(psort_u128_t));
+    memcpy(a_p, base, (size_t)n * sizeof(psort_u128_t));
+
+    double t0 = now_sec();
+    qsort(a_q, (size_t)n, sizeof(psort_u128_t), cmp_u128);
+    double t1 = now_sec();
+
+    double t2 = now_sec();
+    psort_u128(a_p, n);
+    double t3 = now_sec();
+
+    int ok_q = is_sorted_u128(a_q, n);
+    int ok_p = is_sorted_u128(a_p, n);
+
+    printf("qsort     time: %.6f s  sorted: %s\n", (t1 - t0), ok_q ? "YES" : "NO");
+    printf("psort_u128 time: %.6f s  sorted: %s\n", (t3 - t2), ok_p ? "YES" : "NO");
+
+    if (!ok_q || !ok_p) {
+        fprintf(stderr, "ERROR: sorting failed\n");
+        free(base); free(a_q); free(a_p);
+        return 1;
+    }
+
+    if (!arrays_equal_u128(a_q, a_p, n)) {
+        fprintf(stderr, "ERROR: outputs differ (qsort vs psort_u128)\n");
+        free(base); free(a_q); free(a_p);
+        return 1;
+    }
+
+    double speedup = (t1 - t0) / (t3 - t2);
+    printf("speedup (qsort/psort): %.3fx\n", speedup);
+
+    free(base);
+    free(a_q);
+    free(a_p);
+    return 0;
+}
+