test: cover printLong

user/pipetest.c

@@ -0,0 +1,79 @@
+#include "ulib.h"
+
+static void printLong(const char* label, long value)
+{
+    print(label);
+    printDec(value);
+    print("\n");
+}
+
+int main(void)
+{
+    print("pipetest: start, pid=");
+    printDec(userGetpid());
+    print("\n");
+
+    int fds[2];
+    long rc = userPipe(fds);
+    printLong("pipetest: userPipe rc=", rc);
+    if (rc < 0) {
+        print("pipetest: pipe() failed\n");
+        return 1;
+    }
+    int readFd = fds[0];
+    int writeFd = fds[1];
+
+    /* nothing written yet: a read must report "would block" (-1), not EOF */
+    char probe[4];
+    long earlyRead = userRead(readFd, probe, sizeof(probe));
+    printLong("pipetest: read before write rc=", earlyRead);
+    if (earlyRead != -1) {
+        print("pipetest: FAIL expected -1 on empty open pipe\n");
+        return 1;
+    }
+
+    const char* payload = "hello through the pipe\n";
+    long written = userWrite(writeFd, payload, stringLength(payload));
+    printLong("pipetest: wrote bytes=", written);
+    if (written != (long)stringLength(payload)) {
+        print("pipetest: FAIL short write\n");
+        return 1;
+    }
+
+    char buffer[64];
+    long got = userRead(readFd, buffer, sizeof(buffer) - 1);
+    if (got < 0) {
+        print("pipetest: FAIL read after write blocked\n");
+        return 1;
+    }
+    buffer[got] = 0;
+    print("pipetest: read back: ");
+    print(buffer);
+
+    userClose(writeFd);
+
+    /* buffer is now empty and the write end is closed: true EOF (0) */
+    long afterClose = userRead(readFd, probe, sizeof(probe));
+    printLong("pipetest: read after writer closed rc=", afterClose);
+    if (afterClose != 0) {
+        print("pipetest: FAIL expected EOF (0) after writer closed\n");
+        return 1;
+    }
+
+    userClose(readFd);
+
+    /* a second independent pipe proves broken-pipe (write with no reader) */
+    int fds2[2];
+    userPipe(fds2);
+    userClose(fds2[0]);
+    long brokenWrite = userWrite(fds2[1], "x", 1);
+    printLong("pipetest: write after reader closed rc=", brokenWrite);
+    if (brokenWrite != -1) {
+        print("pipetest: FAIL expected broken pipe (-1)\n");
+        return 1;
+    }
+    userClose(fds2[1]);
+
+    print("pipetest: done\n");
+    return 0;
+}