diff --git a/src/prioqTest.c b/src/prioqTest.c
new file mode 100644
index 0000000..e427aad
--- /dev/null
+++ b/src/prioqTest.c
@@ -0,0 +1,182 @@
+#include "ktest.h"
+#include "prioq.h"
+#include "heap.h"
+
+/* Fisher-Yates over a small LCG so insertion order is scrambled but
+   reproducible across runs (same generator as rbtTest.c's shuffle). */
+static void shuffle(uint32* arr, int32 n, uint32 seed)
+{
+    uint32 state = seed;
+    for (int32 i = n - 1; i > 0; i--) {
+        state = state * 1664525u + 1013904223u;
+        int32 j = (int32)(state % (uint32)(i + 1));
+        uint32 tmp = arr[i];
+        arr[i] = arr[j];
+        arr[j] = tmp;
+    }
+}
+
+KTEST(prioqEmptyQueue)
+{
+    PrioQueue q;
+    prioqInit(&q);
+
+    KT_TRUE(t, prioqIsEmpty(&q));
+    KT_EQ(t, prioqCount(&q), 0);
+    KT_NULL(t, prioqPeekMin(&q));
+    KT_NULL(t, prioqPopMin(&q));
+}
+
+KTEST(prioqOrdersByVruntimeAscending)
+{
+    PrioQueue q;
+    prioqInit(&q);
+
+    PrioQNode nodes[5];
+    uint64 vruntimes[] = { 300, 100, 500, 200, 400 };
+    for (uint32 i = 0; i < 5; i++)
+        prioqInsert(&q, &nodes[i], vruntimes[i], i);
+
+    KT_EQ(t, prioqCount(&q), 5);
+
+    uint64 expected[] = { 100, 200, 300, 400, 500 };
+    for (uint32 i = 0; i < 5; i++) {
+        PrioQNode* min = prioqPopMin(&q);
+        KT_NOTNULL(t, min);
+        if (min)
+            KT_EQU(t, min->vruntime, expected[i]);
+    }
+    KT_TRUE(t, prioqIsEmpty(&q));
+}
+
+KTEST(prioqPeekDoesNotRemove)
+{
+    PrioQueue q;
+    prioqInit(&q);
+
+    PrioQNode a, b;
+    prioqInsert(&q, &a, 50, 1);
+    prioqInsert(&q, &b, 10, 2);
+
+    PrioQNode* peeked = prioqPeekMin(&q);
+    KT_NOTNULL(t, peeked);
+    if (peeked)
+        KT_EQ(t, peeked->id, 2);
+    KT_EQ(t, prioqCount(&q), 2);
+
+    PrioQNode* popped = prioqPopMin(&q);
+    KT_EQP(t, popped, peeked);
+    KT_EQ(t, prioqCount(&q), 1);
+}
+
+KTEST(prioqTiesBreakByIdAscending)
+{
+    PrioQueue q;
+    prioqInit(&q);
+
+    PrioQNode nodes[4];
+    uint32 ids[] = { 7, 3, 9, 1 };
+    for (uint32 i = 0; i < 4; i++)
+        prioqInsert(&q, &nodes[i], 1000, ids[i]); /* identical vruntime */
+
+    uint32 expected[] = { 1, 3, 7, 9 };
+    for (uint32 i = 0; i < 4; i++) {
+        PrioQNode* min = prioqPopMin(&q);
+        KT_NOTNULL(t, min);
+        if (min)
+            KT_EQ(t, min->id, expected[i]);
+    }
+}
+
+KTEST(prioqRemoveArbitraryNodePreservesOrder)
+{
+    PrioQueue q;
+    prioqInit(&q);
+
+    PrioQNode nodes[4];
+    uint64 vruntimes[] = { 10, 20, 30, 40 };
+    for (uint32 i = 0; i < 4; i++)
+        prioqInsert(&q, &nodes[i], vruntimes[i], i);
+
+    prioqRemove(&q, &nodes[1]); /* drop vruntime=20 before it is ever popped */
+    KT_EQ(t, prioqCount(&q), 3);
+
+    uint64 expected[] = { 10, 30, 40 };
+    for (uint32 i = 0; i < 3; i++) {
+        PrioQNode* min = prioqPopMin(&q);
+        KT_NOTNULL(t, min);
+        if (min)
+            KT_EQU(t, min->vruntime, expected[i]);
+    }
+    KT_TRUE(t, prioqIsEmpty(&q));
+}
+
+KTEST(prioqNodeStorageIsReusableAcrossQueueLifetimes)
+{
+    PrioQNode node;
+
+    PrioQueue first;
+    prioqInit(&first);
+    prioqInsert(&first, &node, 500, 42);
+    PrioQNode* popped = prioqPopMin(&first);
+    KT_EQP(t, popped, &node);
+
+    /* Same PrioQNode storage, brand new queue: rbtInsert must not be
+       tripped up by stale left/right/parent pointers left over from the
+       first tree. */
+    PrioQueue second;
+    prioqInit(&second);
+    prioqInsert(&second, &node, 5, 1);
+    KT_EQ(t, prioqCount(&second), 1);
+    PrioQNode* min = prioqPeekMin(&second);
+    KT_NOTNULL(t, min);
+    if (min)
+        KT_EQU(t, min->vruntime, 5);
+}
+
+#define prioqStressN 300
+
+KTEST(prioqStressDrainsInFullyAscendingOrder)
+{
+    PrioQNode* pool = (PrioQNode*)kmalloc(sizeof(PrioQNode) * prioqStressN);
+    uint32* order = (uint32*)kmalloc(sizeof(uint32) * prioqStressN);
+    KT_NOTNULL(t, pool);
+    KT_NOTNULL(t, order);
+    if (!pool || !order) {
+        kfree(pool);
+        kfree(order);
+        return;
+    }
+
+    for (uint32 i = 0; i < prioqStressN; i++)
+        order[i] = i;
+    shuffle(order, prioqStressN, 0xFEEDFACEu);
+
+    PrioQueue q;
+    prioqInit(&q);
+    for (uint32 i = 0; i < prioqStressN; i++) {
+        uint32 id = order[i];
+        /* vruntime = id * 3 keeps a strict, checkable total order while
+           still exercising ids that arrive in scrambled sequence. */
+        prioqInsert(&q, &pool[id], (uint64)id * 3, id);
+    }
+    KT_EQ(t, prioqCount(&q), prioqStressN);
+
+    uint64 lastVruntime = 0;
+    uint32 visited = 0;
+    for (;;) {
+        PrioQNode* min = prioqPopMin(&q);
+        if (!min)
+            break;
+        if (visited > 0)
+            KT_TRUE(t, min->vruntime >= lastVruntime);
+        lastVruntime = min->vruntime;
+        KT_EQU(t, min->vruntime, (uint64)min->id * 3);
+        visited++;
+    }
+    KT_EQ(t, visited, prioqStressN);
+    KT_TRUE(t, prioqIsEmpty(&q));
+
+    kfree(pool);
+    kfree(order);
+}