Simplified unit testing of sandboxing code.

sandbox/linux/tests/unit_tests.h

Index: sandbox/linux/tests/unit_tests.h
diff --git a/sandbox/linux/tests/unit_tests.h b/sandbox/linux/tests/unit_tests.h
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+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef SANDBOX_LINUX_TESTS_UNIT_TESTS_H__
+#define SANDBOX_LINUX_TESTS_UNIT_TESTS_H__
+
+#include "base/basictypes.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace sandbox {
+
+// Define a new test case that runs inside of a death test. This is necessary,
+// as most of our tests by definition make global and irreversible changes to
+// the system (i.e. they install a sandbox). GTest provides death tests as a
+// tool to isolate global changes from the rest of the tests.
+#define SANDBOX_TEST(test_case_name, test_name)                               \
+  void TEST_##test_name(void *);                                              \
+  TEST(test_case_name, test_name) {                                           \
+    sandbox::UnitTests::RunTestInProcess(TEST_##test_name, NULL);             \
+  }                                                                           \
+  void TEST_##test_name(void *)
+
+// Simple assertion macro that is compatible with running inside of a death
+// test. We unfortunately cannot use any of the GTest macros.
+#define SANDBOX_STR(x) #x
+#define SANDBOX_ASSERT(expr)                                                  \
+  ((expr)                                                                     \
+   ? static_cast<void>(0)                                                     \
+   : sandbox::UnitTests::AssertionFailure(SANDBOX_STR(expr),                  \
+                                          __FILE__, __LINE__))
+
+class UnitTests {
+ public:
+  typedef void (*Test)(void *);
+
+  // Runs a test inside a short-lived process. Do not call this function
+  // directly. It is automatically invoked by SANDBOX_TEST(). Most sandboxing
+  // functions make global irreversible changes to the execution environment
+  // and must therefore execute in their own isolated process.
+  static void RunTestInProcess(Test test, void *arg);
+
+  // Report a useful error message and terminate the current SANDBOX_TEST().
+  // Calling this function from outside a SANDBOX_TEST() is unlikely to do
+  // anything useful.
+  static void AssertionFailure(const char *expr, const char *file, int line);
+
+ private:
+  DISALLOW_IMPLICIT_CONSTRUCTORS(UnitTests);
+};
+
+}  // namespace
+
+#endif  // SANDBOX_LINUX_TESTS_UNIT_TESTS_H__