Add <error.h>.

Bug: https://code.google.com/p/android/issues/detail?id=79170
Change-Id: Id91765fac45124545e2674a5b2c814707c1a448b
diff --git a/tests/error_test.cpp b/tests/error_test.cpp
new file mode 100644
index 0000000..5fee16f
--- /dev/null
+++ b/tests/error_test.cpp
@@ -0,0 +1,72 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *  * Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *  * 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 COPYRIGHT HOLDERS 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
+ * COPYRIGHT OWNER 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 <gtest/gtest.h>
+
+#include <error.h>
+
+#include "BionicDeathTest.h"
+
+static size_t g_test_error_print_progname_invocation_count;
+
+static void test_error_print_progname() {
+  ++g_test_error_print_progname_invocation_count;
+}
+
+TEST(error, smoke) {
+  error_message_count = 0;
+  error(0, 0, "oops");
+  ASSERT_EQ(1U, error_message_count);
+  error(0, ENOENT, "couldn't open file '%s'", "blah");
+  ASSERT_EQ(2U, error_message_count);
+
+  error_print_progname = test_error_print_progname;
+  g_test_error_print_progname_invocation_count = 0;
+  error(0, 0, "oops");
+  ASSERT_EQ(1U, g_test_error_print_progname_invocation_count);
+
+  error_at_line(0, 0, "blah.c", 123, "hello %s", "world");
+
+  error_print_progname = NULL;
+}
+
+TEST(error_DeathTest, error_exit) {
+  ASSERT_EXIT(error(22, 0, "x%c", 'y'), ::testing::ExitedWithCode(22), "xy");
+}
+
+TEST(error_DeathTest, error_exit_with_errno) {
+  ASSERT_EXIT(error(22, EBADF, "x%c", 'y'), ::testing::ExitedWithCode(22), ": xy: Bad file descriptor");
+}
+
+TEST(error_DeathTest, error_at_line_exit) {
+  ASSERT_EXIT(error_at_line(22, 0, "a.c", 123, "x%c", 'y'), ::testing::ExitedWithCode(22), ":a.c:123: xy");
+}
+
+TEST(error_DeathTest, error_at_line_exit_with_errno) {
+  ASSERT_EXIT(error_at_line(22, EBADF, "a.c", 123, "x%c", 'y'), ::testing::ExitedWithCode(22), ":a.c:123: xy: Bad file descriptor");
+}