diff --git a/llvm/unittests/Support/CommandLineTest.cpp b/llvm/unittests/Support/CommandLineTest.cpp
new file mode 100644
index 0000000..70d6950
--- /dev/null
+++ b/llvm/unittests/Support/CommandLineTest.cpp
@@ -0,0 +1,48 @@
+//===- llvm/unittest/Support/CommandLineTest.cpp - CommandLine tests ------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Support/CommandLine.h"
+
+#include "gtest/gtest.h"
+
+#include <string>
+#include <stdlib.h>
+
+using namespace llvm;
+
+namespace {
+
+class TempEnvVar {
+ public:
+  TempEnvVar(const char *name, const char *value)
+      : name(name) {
+    const char *old_value = getenv(name);
+    EXPECT_EQ(NULL, old_value) << old_value;
+    setenv(name, value, true);
+  }
+
+  ~TempEnvVar() {
+    unsetenv(name);
+  }
+
+ private:
+  const char *const name;
+};
+
+const char test_env_var[] = "LLVM_TEST_COMMAND_LINE_FLAGS";
+
+cl::opt<std::string> EnvironmentTestOption("env-test-opt");
+TEST(CommandLineTest, ParseEnvironment) {
+  TempEnvVar TEV(test_env_var, "-env-test-opt=hello");
+  EXPECT_EQ("", EnvironmentTestOption);
+  cl::ParseEnvironmentOptions("CommandLineTest", test_env_var);
+  EXPECT_EQ("hello", EnvironmentTestOption);
+}
+
+}  // anonymous namespace