--- /dev/null
+++ Libc/Libc-1669.40.2/tests/realpath.c
@@ -0,0 +1,135 @@
+/* $NetBSD: t_realpath.c,v 1.2 2012/03/27 07:54:58 njoly Exp $ */
+
+/*-
+ * Copyright (c) 2012 The NetBSD Foundation, Inc.
+ * All rights reserved.
+ *
+ * This code is derived from software contributed to The NetBSD Foundation
+ * by Jukka Ruohonen.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
+ * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+ * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+#include <sys/cdefs.h>
+__RCSID("$NetBSD: t_realpath.c,v 1.2 2012/03/27 07:54:58 njoly Exp $");
+
+#include <sys/param.h>
+
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <darwintest.h>
+#include <darwintest_utils.h>
+
+struct testcase {
+	const char *path;
+	const char *result;
+};
+
+static const struct testcase paths[] = {
+	{ "/",			"/"		},
+	{ "///////",		"/"		},
+	{ "",			NULL		},
+	{ "       ",		NULL		},
+	{ "/      ",		NULL		},
+	{ "      /",		NULL		},
+	{ "/usr/bin///",	"/usr/bin"	},
+	{ "///////usr",		"/usr"		},
+	{ "/a/b/c/d/e",		NULL		},
+	{ "    /usr/bin	   ",	NULL		},
+	{ "\\//////usr//bin",	NULL		},
+	{ "//usr//bin//",	"/usr/bin"	},
+	{ "//////usr//bin//",	"/usr/bin"	},
+	{ "/usr/bin//////////", "/usr/bin"	},
+};
+
+T_DECL(realpath_basic, "Resolve various short directory paths")
+{
+	char buf[MAXPATHLEN];
+	char *ptr;
+	size_t i;
+
+	size_t num_cases = sizeof(paths) / sizeof(struct testcase);
+	for (i = 0; i < num_cases; i++) {
+
+		(void)memset(buf, '\0', sizeof(buf));
+
+		ptr = realpath(paths[i].path, buf);
+
+		if (paths[i].result == NULL) {
+			T_EXPECT_NULL(ptr, NULL);
+		} else {
+			T_EXPECT_EQ_STR(ptr, paths[i].result, "Real path matches expected path");
+		}
+	}
+}
+
+T_DECL(realpath_trailing, "Trailing . and .. should fail after non-directories")
+{
+	char result[MAXPATHLEN] = { 0 };
+
+	T_EXPECT_NULL(realpath("/usr/null/.", result), NULL);
+	T_EXPECT_NULL(realpath("/usr/null/..", result), NULL);
+}
+
+T_DECL(realpath_huge, "Test realpath with maximum path size")
+{
+	char result[MAXPATHLEN] = { 0 };
+	char buffer[MAXPATHLEN] = { 0 };
+
+	(void)memset(buffer, '/', sizeof(buffer) - 1);
+
+	T_EXPECT_NOTNULL(realpath(buffer, result), NULL);
+	T_EXPECT_EQ(strlen(result), (size_t) 1, NULL);
+	T_EXPECT_EQ(result[0], '/', NULL);
+}
+
+T_DECL(realpath_symlink, "Resolve symlinked paths")
+{
+	char *resolved_tmpdir;
+	char path[MAXPATHLEN] = { 0 };
+	char slnk[MAXPATHLEN] = { 0 };
+	char resb[MAXPATHLEN] = { 0 };
+	int fd;
+
+	// We have to use the realpath for this symlink test.
+	// Otherwise, when trying to resolve a symlink, it won't match.
+	resolved_tmpdir = realpath(dt_tmpdir(), NULL);
+	snprintf(path, sizeof(path), "%s%s", resolved_tmpdir, "/real");
+	snprintf(slnk, sizeof(path), "%s%s", resolved_tmpdir, "/sym");
+
+	fd = open(path, O_RDONLY | O_CREAT, 0600);
+
+	T_WITH_ERRNO;
+	T_ASSERT_GE(fd, 0, NULL);
+	T_ASSERT_POSIX_ZERO(symlink(path, slnk), NULL);
+	T_ASSERT_POSIX_ZERO(close(fd), NULL);
+
+	T_ASSERT_NOTNULL(realpath(slnk, resb), NULL);
+	T_ASSERT_EQ_STR(resb, path, NULL);
+
+	T_ASSERT_POSIX_ZERO(unlink(path), NULL);
+	T_ASSERT_POSIX_ZERO(unlink(slnk), NULL);
+	free(resolved_tmpdir);
+}