Add tests from the old svn tree

We're losing the svn history (which we could probably keep if we tried
hard enough) but don't consider that worthwhile.

Note these tests are destructive, so run them only in a throwaway
environment like a chroot, container, or vm.

The tests/run.all script should be the one which launches all the tests.

Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>

tests/common/time_past.c

@@ -0,0 +1,52 @@
+/* 
+ * gcc time_past.c -o time_past.so -shared -ldl 
+ * LD_PRELOAD=./time_past.so PAST_DAYS=2 ./test
+ */
+
+#define _GNU_SOURCE
+#include <dlfcn.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <stdarg.h>
+#include <fcntl.h>
+#include <string.h>
+#include <errno.h>
+#include <assert.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+
+
+typedef time_t (*time_type) (time_t *t);
+static time_type next_time;
+
+static int time_past = 0;
+static char *past = NULL;
+
+time_t time (time_t *t)
+{
+	time_t res;
+
+	if (NULL == next_time)
+	{
+		next_time = dlsym (RTLD_NEXT, "time");
+		assert (NULL != next_time);
+	}
+	if (NULL == past) {
+		const char *past = getenv ("PAST_DAYS");
+		if (NULL == past) {
+			fputs ("No PAST_DAYS defined\n", stderr);
+		}
+		time_past = atoi (past);
+	}
+
+	res = next_time (t);
+	res -= 24*60*60*time_past;
+
+	if (NULL != t) {
+		*t = res;
+	}
+
+	return res;
+}
+