tests: Introduce torture_create_temp_file()

Introduced torture_create_temp_file() and torture_close_fp() to allow
creating temprary files transparently in Unix and Windows environment.
This also adds a unit test for the added functions.

Signed-off-by: Anderson Toshiyuki Sasaki <ansasaki@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>

tests/unittests/torture_temp_file.c

@@ -0,0 +1,63 @@
+#include "config.h"
+
+#include "torture.h"
+#define LIBSSH_STATIC
+
+const char template[] = "/tmp/temp_file_XXXXXX";
+
+static int setup(void **state)
+{
+    char *file_name = NULL;
+
+    file_name  = torture_create_temp_file(template);
+    assert_non_null(file_name);
+
+    *state = (void *)file_name;
+
+    return 0;
+}
+
+static int teardown(void **state)
+{
+    int rc;
+    char *file_name = *((char **)state);
+
+    assert_non_null(file_name);
+
+    rc = unlink(file_name);
+    assert_int_equal(rc, 0);
+
+    SAFE_FREE(file_name);
+
+    return 0;
+}
+
+
+static void torture_temp_file(void **state)
+{
+    char *file_name = *((char **)state);
+    FILE *fp = NULL;
+
+    assert_non_null(file_name);
+
+    fp = fopen(file_name, "r");
+    assert_non_null(fp);
+
+    fclose(fp);
+
+    printf("Created temp file: %s\n", file_name);
+}
+
+int torture_run_tests(void)
+{
+    int rc;
+    struct CMUnitTest tests[] = {
+        cmocka_unit_test_setup_teardown(torture_temp_file, setup, teardown),
+    };
+
+    torture_filter_tests(tests);
+    rc = cmocka_run_group_tests(tests, NULL, NULL);
+
+    return rc;
+}
+