tests: Add fifo_test.

Creates, opens, tries to open as directory, then unlinks.

The attempt to open as a directory triggers an assertion
in the kernel at present (this is #17870.) The next commit
will fix that.

src/tests/system/libroot/posix/Jamfile

@@ -14,6 +14,7 @@ SimpleTest calloc_test : calloc_test.c ;
 SimpleTest <test>chmod : chmod.cpp ;
 SimpleTest clearenv : clearenv.cpp ;
 SimpleTest dirent_test : dirent_test.cpp ;
+SimpleTest fifo_test : fifo_test.cpp ;
 SimpleTest flock_test : flock_test.cpp ;
 SimpleTest fseek_test : fseek_test.cpp ;
 SimpleTest getsubopt_test : getsubopt_test.cpp ;

src/tests/system/libroot/posix/fifo_test.cpp

@@ -0,0 +1,38 @@
+#include <dirent.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <errno.h>
+
+int
+main(int argc, char** argv)
+{
+	const char* filename = "temp.fifo";
+
+	if (mkfifo("temp.fifo", S_IRWXU) != 0) {
+		perror("mkfifo error");
+		return 1;
+	}
+
+	int rfd = open(filename, O_RDONLY | O_NONBLOCK);
+	if (rfd < 0) {
+		perror("open() error");
+		return 1;
+	}
+
+	DIR* dir = opendir(filename);
+	if (dir != NULL) {
+		perror("opendir succeeded");
+		return 1;
+	}
+
+	dir = fdopendir(rfd);
+	if (dir != NULL) {
+		perror("fdopendir succeeded");
+		return 1;
+	}
+
+	unlink(filename);
+	return 0;
+}