test: cover pipeBlockTest

src/pipeBlockTest.c

@@ -0,0 +1,113 @@
+#include "ktest.h"
+#include "pipe.h"
+#include "string.h"
+
+/*
+ * pipeReadBlocking/pipeWriteBlocking only return without parking the thread
+ * when the very first attempt already resolves (data/space/EOF/broken-pipe
+ * already true) - any scenario that would genuinely need to park calls
+ * halt(), which requires a live, interrupt-driven scheduler to ever resume
+ * from. ktestRunAll() runs before schedStart() (see ktest.h) on the sole
+ * execution context there is, so these tests deliberately only cover the
+ * "resolves immediately, never blocks" paths. The genuine cross-thread
+ * park/wake handshake is exercised for real at boot by the producer/consumer
+ * demo in kmain.c (needle "pipe demo: eof, count=10" in tools/ci-test.sh).
+ */
+
+KTEST(pipeReadBlockingReturnsQueuedDataImmediately)
+{
+    int h = pipeCreate();
+    KT_GE(t, h, 0);
+
+    const char* msg = "already here";
+    KT_EQ(t, pipeWrite(h, msg, strlen(msg)), (int64)strlen(msg));
+
+    char buffer[32];
+    memset(buffer, 0, sizeof(buffer));
+    int64 got = pipeReadBlocking(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(pipeReadBlockingReturnsEofWithoutParking)
+{
+    int h = pipeCreate();
+    KT_GE(t, h, 0);
+
+    pipeCloseWrite(h);
+
+    char buffer[8];
+    KT_EQ(t, pipeReadBlocking(h, buffer, sizeof(buffer)), 0);
+
+    pipeCloseRead(h);
+}
+
+KTEST(pipeReadBlockingRejectsInvalidHandleWithoutParking)
+{
+    char buffer[8];
+    KT_EQ(t, pipeReadBlocking(-1, buffer, sizeof(buffer)), -1);
+    KT_EQ(t, pipeReadBlocking(999, buffer, sizeof(buffer)), -1);
+}
+
+KTEST(pipeWriteBlockingSucceedsImmediatelyWhenRoomExists)
+{
+    int h = pipeCreate();
+    KT_GE(t, h, 0);
+
+    const char* msg = "room to spare";
+    int64 written = pipeWriteBlocking(h, msg, strlen(msg));
+    KT_EQ(t, written, (int64)strlen(msg));
+
+    char buffer[32];
+    memset(buffer, 0, sizeof(buffer));
+    KT_EQ(t, pipeRead(h, buffer, sizeof(buffer)), (int64)strlen(msg));
+
+    pipeCloseRead(h);
+    pipeCloseWrite(h);
+}
+
+KTEST(pipeWriteBlockingOnBrokenPipeReturnsWithoutParking)
+{
+    int h = pipeCreate();
+    KT_GE(t, h, 0);
+
+    pipeCloseRead(h);
+
+    const char* msg = "nobody listening";
+    KT_EQ(t, pipeWriteBlocking(h, msg, strlen(msg)), -1);
+
+    pipeCloseWrite(h);
+}
+
+KTEST(pipeWriteBlockingRejectsInvalidHandleWithoutParking)
+{
+    char buffer[4] = { 0 };
+    KT_EQ(t, pipeWriteBlocking(-1, buffer, sizeof(buffer)), -1);
+    KT_EQ(t, pipeWriteBlocking(999, buffer, sizeof(buffer)), -1);
+}
+
+KTEST(pipeWriteBlockingSucceedsRightAfterDrainFreesRoom)
+{
+    int h = pipeCreate();
+    KT_GE(t, h, 0);
+
+    uint8 chunk[pipeBufferSize];
+    memset(chunk, 0x5A, sizeof(chunk));
+
+    KT_EQ(t, pipeWrite(h, chunk, sizeof(chunk)), (int64)sizeof(chunk));
+
+    /* buffer is completely full: a blocking write would have to park here if
+       nothing ever drained it, so proving this call returns at all (rather
+       than hanging the whole test run) is exactly the point. */
+    uint8 drained[16];
+    KT_EQ(t, pipeRead(h, drained, sizeof(drained)), (int64)sizeof(drained));
+
+    int64 written = pipeWriteBlocking(h, chunk, sizeof(drained));
+    KT_EQ(t, written, (int64)sizeof(drained));
+
+    pipeCloseRead(h);
+    pipeCloseWrite(h);
+}