tests: Add unit test for libusb_set_option

The behavior of libusb_set_option was not matching the documentation
when the log level was set in the environment. This has been fixed but a
regression test is needed to ensure the behavior does not deviate. This
commit adds a set of unit tests to cover some of the functionality of
libusb_set_option.

Closes #1245

Signed-off-by: Nathan Hjelm <hjelmn@google.com>
[Xiaofan: Add Windows setenv/unsetenv wrappers]
Signed-off-by: Xiaofan Chen <xiaofanc@gmail.com>
[Tormod: Fix test_no_discovery() build on Linux, add msvc build]
Signed-off-by: Tormod Volden <debian.tormod@gmail.com>

2 files changed, 205 insertions, 2 deletions

diff --git a/tests/Makefile.am b/tests/Makefile.am
index d47d4ed..18da1eb 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -2,9 +2,12 @@ AM_CPPFLAGS = -I$(top_srcdir)/libusb
 LDADD = ../libusb/libusb-1.0.la
 LIBS =
 
-stress_SOURCES = stress.c libusb_testlib.h testlib.c
+stress_SOURCES = stress.c testlib.c
 
-noinst_PROGRAMS = stress
+set_option_SOURCES = set_option.c testlib.c
+
+noinst_HEADERS = libusb_testlib.h
+noinst_PROGRAMS = stress set_option
 
 if PLATFORM_POSIX
 stress_mt_SOURCES = stress_mt.c
diff --git a/tests/set_option.c b/tests/set_option.c
new file mode 100644
index 0000000..c04e4ea
--- /dev/null
+++ b/tests/set_option.c
@@ -0,0 +1,200 @@
+/* -*- Mode: C; indent-tabs-mode:nil -*- */
+/*
+ * Unit tests for libusb_set_option
+ * Copyright © 2023 Nathan Hjelm <hjelmn@cs.unm.edu>
+ * Copyright © 2023 Google, LLC. All rights reserved.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "config.h"
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <inttypes.h>
+#include "libusbi.h"
+#include "libusb_testlib.h"
+
+#if defined(_WIN32) && !defined(__CYGWIN__)
+#include <winbase.h>
+
+static int unsetenv(const char *env) {
+  return _putenv_s(env, "");
+}
+
+static int setenv(const char *env, const char *value, int overwrite) {
+  if (getenv(env) && !overwrite)
+    return 0;
+  return _putenv_s(env, value);
+}
+#endif
+
+#define LIBUSB_TEST_CLEAN_EXIT(code) \
+  do {                               \
+    if (test_ctx != NULL) {          \
+      libusb_exit(test_ctx);         \
+    }                                \
+    unsetenv("LIBUSB_DEBUG");        \
+    return (code);                   \
+  } while (0)
+
+/**
+ * Fail the test if the expression does not evaluate to LIBUSB_SUCCESS.
+ */
+#define LIBUSB_TEST_RETURN_ON_ERROR(expr)                       \
+  do {                                                          \
+    int _result = (expr);                                       \
+    if (LIBUSB_SUCCESS != _result) {                            \
+      libusb_testlib_logf("Not success (%s) at %s:%d", #expr,   \
+                          __FILE__, __LINE__);                  \
+      LIBUSB_TEST_CLEAN_EXIT(TEST_STATUS_FAILURE);              \
+    }                                                           \
+  } while (0)
+
+/**
+ * Use relational operatator to compare two values and fail the test if the
+ * comparison is false. Intended to compare integer or pointer types.
+ *
+ * Example: LIBUSB_EXPECT(==, 0, 1) -> fail, LIBUSB_EXPECT(==, 0, 0) -> ok.
+ */
+#define LIBUSB_EXPECT(operator, lhs, rhs)                               \
+  do {                                                                  \
+    int64_t _lhs = (lhs), _rhs = (rhs);                                 \
+    if (!(_lhs operator _rhs)) {                                        \
+      libusb_testlib_logf("Expected %s (%" PRId64 ") " #operator        \
+                          " %s (%" PRId64 ") at %s:%d", #lhs,           \
+                          (int64_t)(intptr_t)_lhs, #rhs,                \
+                          (int64_t)(intptr_t)_rhs, __FILE__,            \
+                          __LINE__);                                    \
+      LIBUSB_TEST_CLEAN_EXIT(TEST_STATUS_FAILURE);                      \
+    }                                                                   \
+  } while (0)
+
+
+static libusb_testlib_result test_set_log_level_basic(void) {
+#if defined(ENABLE_LOGGING) && !defined(ENABLE_DEBUG_LOGGING)
+  libusb_context *test_ctx = NULL;
+
+  /* unset LIBUSB_DEBUG if it is set */
+  unsetenv("LIBUSB_DEBUG");
+
+  /* test basic functionality */
+  LIBUSB_TEST_RETURN_ON_ERROR(libusb_init_context(&test_ctx, /*options=*/NULL,
+                                                  /*num_options=*/0));
+  LIBUSB_TEST_RETURN_ON_ERROR(libusb_set_option(test_ctx,
+                                                LIBUSB_OPTION_LOG_LEVEL,
+                                                LIBUSB_LOG_LEVEL_ERROR));
+  LIBUSB_EXPECT(==, test_ctx->debug, LIBUSB_LOG_LEVEL_ERROR);
+  LIBUSB_TEST_RETURN_ON_ERROR(libusb_set_option(test_ctx,
+                                                LIBUSB_OPTION_LOG_LEVEL,
+                                                LIBUSB_LOG_LEVEL_NONE));
+  LIBUSB_EXPECT(==, test_ctx->debug, LIBUSB_LOG_LEVEL_NONE);
+
+  LIBUSB_TEST_CLEAN_EXIT(TEST_STATUS_SUCCESS);
+#else
+  return TEST_STATUS_SKIP;
+#endif
+}
+
+static libusb_testlib_result test_set_log_level_default(void) {
+#if defined(ENABLE_LOGGING) && !defined(ENABLE_DEBUG_LOGGING)
+  libusb_context *test_ctx = NULL;
+
+  /* set the default debug level */
+  LIBUSB_TEST_RETURN_ON_ERROR(libusb_set_option(NULL, LIBUSB_OPTION_LOG_LEVEL,
+                                                LIBUSB_LOG_LEVEL_ERROR));
+
+  LIBUSB_TEST_RETURN_ON_ERROR(libusb_init_context(&test_ctx, /*options=*/NULL,
+                                                  /*num_options=*/0));
+  /* check that debug level came from the default */
+  LIBUSB_EXPECT(==, test_ctx->debug, LIBUSB_LOG_LEVEL_ERROR);
+
+  /* try to override the old log level. since this was set from the default it
+   * should be possible to change it */
+  LIBUSB_TEST_RETURN_ON_ERROR(libusb_set_option(test_ctx,
+                                                LIBUSB_OPTION_LOG_LEVEL,
+                                                LIBUSB_LOG_LEVEL_NONE));
+  LIBUSB_EXPECT(==, test_ctx->debug, LIBUSB_LOG_LEVEL_NONE);
+
+  LIBUSB_TEST_CLEAN_EXIT(TEST_STATUS_SUCCESS);
+#else
+  return TEST_STATUS_SKIP;
+#endif
+}
+
+static libusb_testlib_result test_set_log_level_env(void) {
+#if defined(ENABLE_LOGGING)
+  libusb_context *test_ctx = NULL;
+
+  /* check that libusb_set_option does not change the log level when it was set
+   * from the environment. */
+  setenv("LIBUSB_DEBUG", "4", /*overwrite=*/0);
+  LIBUSB_TEST_RETURN_ON_ERROR(libusb_init_context(&test_ctx, /*options=*/NULL,
+                                                  /*num_options=*/0));
+  LIBUSB_EXPECT(==, test_ctx->debug, 4);
+
+  LIBUSB_TEST_RETURN_ON_ERROR(libusb_set_option(test_ctx,
+                                                LIBUSB_OPTION_LOG_LEVEL,
+                                                LIBUSB_LOG_LEVEL_ERROR));
+  /* environment variable should always override LIBUSB_OPTION_LOG_LEVEL if set */
+  LIBUSB_EXPECT(==, test_ctx->debug, 4);
+
+  LIBUSB_TEST_CLEAN_EXIT(TEST_STATUS_SUCCESS);
+#else
+  return TEST_STATUS_SKIP;
+#endif
+}
+
+
+static libusb_testlib_result test_no_discovery(void)
+{
+#if defined(__linux__)
+  libusb_context *test_ctx;
+  LIBUSB_TEST_RETURN_ON_ERROR(libusb_init_context(&test_ctx, /*options=*/NULL,
+                                                  /*num_options=*/0));
+  libusb_device **device_list = NULL;
+  ssize_t num_devices = libusb_get_device_list(test_ctx, &device_list);
+  libusb_free_device_list(device_list, /*unref_devices=*/1);
+  libusb_exit(test_ctx);
+
+  LIBUSB_EXPECT(>, num_devices, 0);
+
+  LIBUSB_TEST_RETURN_ON_ERROR(libusb_set_option(NULL, LIBUSB_OPTION_NO_DEVICE_DISCOVERY));
+  LIBUSB_TEST_RETURN_ON_ERROR(libusb_init_context(&test_ctx, /*options=*/NULL,
+                                                  /*num_options=*/0));
+  device_list = NULL;
+  num_devices = libusb_get_device_list(test_ctx, &device_list);
+  libusb_free_device_list(device_list, /*unref_devices=*/1);
+
+  LIBUSB_EXPECT(==, num_devices, 0);
+  LIBUSB_TEST_CLEAN_EXIT(TEST_STATUS_SUCCESS);
+#else
+  return TEST_STATUS_SKIP;
+#endif
+}
+
+static const libusb_testlib_test tests[] = {
+  { "test_set_log_level_basic", &test_set_log_level_basic },
+  { "test_set_log_level_env", &test_set_log_level_env },
+  { "test_no_discovery", &test_no_discovery },
+  /* since default options can't be unset, run this one last */
+  { "test_set_log_level_default", &test_set_log_level_default },
+  LIBUSB_NULL_TEST
+};
+
+int main(int argc, char *argv[])
+{
+  return libusb_testlib_run_tests(argc, argv, tests);
+}