diff --git a/clang/test/Analysis/unix-api.cpp b/clang/test/Analysis/unix-api.cpp
new file mode 100644
index 0000000..1c8f996
--- /dev/null
+++ b/clang/test/Analysis/unix-api.cpp
@@ -0,0 +1,62 @@
+// RUN: %clang_cc1 -analyze -analyzer-checker=core,unix.API -verify %s
+extern "C" {
+#ifndef O_RDONLY
+#define O_RDONLY 0
+#endif
+
+#ifndef NULL
+#define NULL ((void*) 0)
+#endif
+
+int open(const char *, int, ...);
+int close(int fildes);
+
+} // extern "C"
+
+namespace MyNameSpace {
+int open(const char *a, int b, int c, int d);
+}
+
+void unix_open(const char *path) {
+  int fd;
+  fd = open(path, O_RDONLY); // no-warning
+  if (fd > -1)
+    close(fd);
+}
+
+void unix_open_misuse(const char *path) {
+  int fd;
+  int mode = 0x0;
+  fd = open(path, O_RDONLY, mode, NULL); // expected-warning{{Call to 'open' with more than 3 arguments}}
+  if (fd > -1)
+    close(fd);
+}
+
+// Don't treat open() in namespaces as the POSIX open()
+void namespaced_open(const char *path) {
+  MyNameSpace::open("Hi", 2, 3, 4); // no-warning
+
+  using namespace MyNameSpace;
+
+  open("Hi", 2, 3, 4); // no-warning
+
+  int fd;
+  int mode = 0x0;
+  fd = ::open(path, O_RDONLY, mode, NULL); // expected-warning{{Call to 'open' with more than 3 arguments}}
+  if (fd > -1)
+    close(fd);
+}
+
+class MyClass {
+public:
+  static int open(const char *a, int b, int c, int d);
+
+  int open(int a, int, int c, int d);
+};
+
+void class_qualified_open() {
+  MyClass::open("Hi", 2, 3, 4); // no-warning
+
+  MyClass mc;
+  mc.open(1, 2, 3, 4); // no-warning
+}