From 9dfdd34540bcfc276bccb6dee9b44f84afc57f7c Mon Sep 17 00:00:00 2001
From: DualFroz <me@dualfroz.com>
Date: Thu, 10 Sep 2026 20:16:16 +0200
Subject: [PATCH] test: cover pipeTest

---
 src/pipeTest.c | 183 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 183 insertions(+)
 create mode 100644 src/pipeTest.c

diff --git a/src/pipeTest.c b/src/pipeTest.c
new file mode 100644
index 0000000..ae5803e
--- /dev/null
+++ b/src/pipeTest.c
@@ -0,0 +1,183 @@
+#include "ktest.h"
+#include "pipe.h"
+#include "string.h"
+
+KTEST(pipeWriteThenReadRoundTrips)
+{
+    int h = pipeCreate();
+    KT_GE(t, h, 0);
+
+    const char* msg = "hello pipe";
+    int64 written = pipeWrite(h, msg, strlen(msg));
+    KT_EQ(t, written, (int64)strlen(msg));
+
+    char buffer[32];
+    memset(buffer, 0, sizeof(buffer));
+    int64 got = pipeRead(h, buffer, sizeof(buffer));
+    KT_EQ(t, got, (int64)strlen(msg));
+    KT_TRUE(t, memcmp(buffer, msg, strlen(msg)) == 0);
+
+    pipeCloseRead(h);
+    pipeCloseWrite(h);
+}
+
+KTEST(pipeReadOnEmptyOpenPipeWouldBlock)
+{
+    int h = pipeCreate();
+    KT_GE(t, h, 0);
+
+    char buffer[8];
+    KT_EQ(t, pipeRead(h, buffer, sizeof(buffer)), -1);
+
+    pipeCloseRead(h);
+    pipeCloseWrite(h);
+}
+
+KTEST(pipeReadZeroLengthIsNoop)
+{
+    int h = pipeCreate();
+    KT_GE(t, h, 0);
+
+    char buffer[1];
+    KT_EQ(t, pipeRead(h, buffer, 0), 0);
+    KT_EQ(t, pipeWrite(h, buffer, 0), 0);
+
+    pipeCloseRead(h);
+    pipeCloseWrite(h);
+}
+
+KTEST(pipeFullWriteWouldBlockThenDrainsAndAcceptsMore)
+{
+    int h = pipeCreate();
+    KT_GE(t, h, 0);
+
+    uint8 chunk[pipeBufferSize];
+    memset(chunk, 0xAB, sizeof(chunk));
+
+    /* this exactly fills the ring. */
+    int64 filled = pipeWrite(h, chunk, sizeof(chunk));
+    KT_EQ(t, filled, (int64)sizeof(chunk));
+
+    /* buffer is full: further write must report "would block" */
+    KT_EQ(t, pipeWrite(h, chunk, 1), -1);
+
+    /* drain some bytes, then more space is available */
+    uint8 drained[64];
+    int64 gotDrain = pipeRead(h, drained, sizeof(drained));
+    KT_EQ(t, gotDrain, (int64)sizeof(drained));
+    for (uint64 i = 0; i < sizeof(drained); i++)
+        KT_EQU(t, drained[i], 0xAB);
+
+    int64 moreWritten = pipeWrite(h, chunk, sizeof(drained));
+    KT_EQ(t, moreWritten, (int64)sizeof(drained));
+
+    pipeCloseRead(h);
+    pipeCloseWrite(h);
+}
+
+KTEST(pipeEofAfterWriterClosedAndBufferDrained)
+{
+    int h = pipeCreate();
+    KT_GE(t, h, 0);
+
+    const char* msg = "last bytes";
+    KT_EQ(t, pipeWrite(h, msg, strlen(msg)), (int64)strlen(msg));
+
+    pipeCloseWrite(h);
+
+    /* data queued before close is still readable */
+    char buffer[32];
+    int64 got = pipeRead(h, buffer, sizeof(buffer));
+    KT_EQ(t, got, (int64)strlen(msg));
+
+    /* now drained and no writer left: true end-of-file, not "would block" */
+    KT_EQ(t, pipeRead(h, buffer, sizeof(buffer)), 0);
+    KT_EQ(t, pipeRead(h, buffer, sizeof(buffer)), 0);
+
+    pipeCloseRead(h);
+}
+
+KTEST(pipeWriteAfterReaderClosedIsBrokenPipe)
+{
+    int h = pipeCreate();
+    KT_GE(t, h, 0);
+
+    pipeCloseRead(h);
+
+    const char* msg = "nobody listening";
+    KT_EQ(t, pipeWrite(h, msg, strlen(msg)), -1);
+
+    pipeCloseWrite(h);
+}
+
+KTEST(pipeInvalidHandleIsRejected)
+{
+    KT_FALSE(t, pipeValid(-1));
+    KT_FALSE(t, pipeValid(999));
+
+    char buffer[4];
+    KT_EQ(t, pipeRead(-1, buffer, sizeof(buffer)), -1);
+    KT_EQ(t, pipeWrite(-1, buffer, sizeof(buffer)), -1);
+
+    /* closing an invalid handle must not crash */
+    pipeCloseRead(-1);
+    pipeCloseWrite(999);
+}
+
+KTEST(pipeIndependentPipesDoNotInterfere)
+{
+    int a = pipeCreate();
+    int b = pipeCreate();
+    KT_GE(t, a, 0);
+    KT_GE(t, b, 0);
+    KT_NE(t, a, b);
+
+    KT_EQ(t, pipeWrite(a, "AAAA", 4), 4);
+    KT_EQ(t, pipeWrite(b, "BB", 2), 2);
+
+    char bufA[8];
+    char bufB[8];
+    memset(bufA, 0, sizeof(bufA));
+    memset(bufB, 0, sizeof(bufB));
+
+    KT_EQ(t, pipeRead(b, bufB, sizeof(bufB)), 2);
+    KT_TRUE(t, memcmp(bufB, "BB", 2) == 0);
+
+    KT_EQ(t, pipeRead(a, bufA, sizeof(bufA)), 4);
+    KT_TRUE(t, memcmp(bufA, "AAAA", 4) == 0);
+
+    pipeCloseRead(a);
+    pipeCloseWrite(a);
+    pipeCloseRead(b);
+    pipeCloseWrite(b);
+}
+
+KTEST(pipeTableExhaustionAndReuse)
+{
+    int handles[maxPipes + 1];
+    int created = 0;
+
+    while (created < maxPipes + 1) {
+        int h = pipeCreate();
+        if (h < 0)
+            break;
+        handles[created++] = h;
+    }
+
+    /* the table must run out before maxPipes+1 succeed */
+    KT_LT(t, created, maxPipes + 1);
+    KT_EQ(t, pipeCreate(), -1);
+
+    /* fully closing one pipe frees its slot for reuse */
+    pipeCloseRead(handles[0]);
+    pipeCloseWrite(handles[0]);
+    int reused = pipeCreate();
+    KT_GE(t, reused, 0);
+
+    pipeCloseRead(reused);
+    pipeCloseWrite(reused);
+    for (int i = 1; i < created; i++) {
+        pipeCloseRead(handles[i]);
+        pipeCloseWrite(handles[i]);
+    }
+}