diff --git a/tests/unistd_test.cpp b/tests/unistd_test.cpp
index 3ccaf3b..3193083 100644
--- a/tests/unistd_test.cpp
+++ b/tests/unistd_test.cpp
@@ -15,6 +15,7 @@
  */
 
 #include <gtest/gtest.h>
+#include "TemporaryFile.h"
 
 #include <stdint.h>
 #include <unistd.h>
@@ -32,3 +33,43 @@
   void* final_break = sbrk(0);
   ASSERT_EQ(final_break, new_break);
 }
+
+TEST(unistd, truncate) {
+  TemporaryFile tf;
+  ASSERT_EQ(0, close(tf.fd));
+  ASSERT_EQ(0, truncate(tf.filename, 123));
+
+  struct stat sb;
+  ASSERT_EQ(0, stat(tf.filename, &sb));
+  ASSERT_EQ(123, sb.st_size);
+}
+
+TEST(unistd, truncate64) {
+  TemporaryFile tf;
+  ASSERT_EQ(0, close(tf.fd));
+  ASSERT_EQ(0, truncate64(tf.filename, 123));
+
+  struct stat sb;
+  ASSERT_EQ(0, stat(tf.filename, &sb));
+  ASSERT_EQ(123, sb.st_size);
+}
+
+TEST(unistd, ftruncate) {
+  TemporaryFile tf;
+  ASSERT_EQ(0, ftruncate(tf.fd, 123));
+  ASSERT_EQ(0, close(tf.fd));
+
+  struct stat sb;
+  ASSERT_EQ(0, stat(tf.filename, &sb));
+  ASSERT_EQ(123, sb.st_size);
+}
+
+TEST(unistd, ftruncate64) {
+  TemporaryFile tf;
+  ASSERT_EQ(0, ftruncate64(tf.fd, 123));
+  ASSERT_EQ(0, close(tf.fd));
+
+  struct stat sb;
+  ASSERT_EQ(0, stat(tf.filename, &sb));
+  ASSERT_EQ(123, sb.st_size);
+}