diff --git a/aos/util/file_test.cc b/aos/util/file_test.cc
new file mode 100644
index 0000000..f904259
--- /dev/null
+++ b/aos/util/file_test.cc
@@ -0,0 +1,40 @@
+#include "aos/util/file.h"
+
+#include <stdlib.h>
+
+#include <string>
+
+#include "gtest/gtest.h"
+
+#include "aos/testing/test_logging.h"
+
+namespace aos {
+namespace util {
+namespace testing {
+
+class FileTest : public ::testing::Test {
+ protected:
+  FileTest() {
+    ::aos::testing::EnableTestLogging();
+  }
+};
+
+// Basic test of reading a normal file.
+TEST_F(FileTest, ReadNormalFile) {
+  const ::std::string tmpdir(getenv("TEST_TMPDIR"));
+  const ::std::string test_file = tmpdir + "/test_file";
+  ASSERT_EQ(0, system(("echo contents > " + test_file).c_str()));
+  EXPECT_EQ("contents\n", ReadFileToStringOrDie(test_file));
+}
+
+// Tests reading a file with 0 size, among other weird things.
+TEST_F(FileTest, ReadSpecialFile) {
+  const ::std::string stat = ReadFileToStringOrDie("/proc/self/stat");
+  EXPECT_EQ('\n', stat[stat.size() - 1]);
+  const ::std::string my_pid = ::std::to_string(getpid());
+  EXPECT_EQ(my_pid, stat.substr(0, my_pid.size()));
+}
+
+}  // namespace testing
+}  // namespace util
+}  // namespace aos