add makeTestHash() helper function

Summary:
Add a helper function to create human-readable hashes in test code without
having to always specify a full 40-byte long string.

Reviewed By: wez

Differential Revision: D4336161

fbshipit-source-id: cf6af58dd788b5553a2a6daef56db43cddbbc04a

eden/fs/testharness/TestUtil.cpp

@@ -0,0 +1,32 @@
+/*
+ *  Copyright (c) 2016, Facebook, Inc.
+ *  All rights reserved.
+ *
+ *  This source code is licensed under the BSD-style license found in the
+ *  LICENSE file in the root directory of this source tree. An additional grant
+ *  of patent rights can be found in the PATENTS file in the same directory.
+ *
+ */
+#include "TestUtil.h"
+
+#include <cstring>
+#include <stdexcept>
+#include "eden/fs/model/Hash.h"
+
+namespace facebook {
+namespace eden {
+Hash makeTestHash(folly::StringPiece value) {
+  constexpr size_t ASCII_SIZE = 2 * Hash::RAW_SIZE;
+  if (value.size() > ASCII_SIZE) {
+    throw std::invalid_argument(value.toString() + " is too big for Hash");
+  }
+  std::array<char, ASCII_SIZE> fullValue;
+  memset(fullValue.data(), '0', fullValue.size());
+  memcpy(
+      fullValue.data() + fullValue.size() - value.size(),
+      value.data(),
+      value.size());
+  return Hash{folly::StringPiece{folly::range(fullValue)}};
+}
+}
+}

eden/fs/testharness/TestUtil.h

@@ -0,0 +1,27 @@
+/*
+ *  Copyright (c) 2016, Facebook, Inc.
+ *  All rights reserved.
+ *
+ *  This source code is licensed under the BSD-style license found in the
+ *  LICENSE file in the root directory of this source tree. An additional grant
+ *  of patent rights can be found in the PATENTS file in the same directory.
+ *
+ */
+#pragma once
+
+#include <folly/Range.h>
+
+namespace facebook {
+namespace eden {
+
+class Hash;
+
+/**
+ * Helper function for creating Hash values to use in tests.
+ *
+ * The input should be an ASCII hex string.  It may be less than 40-bytes long,
+ * in which case it will be sign-extended to 40 bytes.
+ */
+Hash makeTestHash(folly::StringPiece value);
+}
+}

eden/fs/testharness/test/TARGETS

@@ -4,6 +4,7 @@ cpp_unittest(
   srcs = glob(['*Test.cpp']),
   deps = [
     '//eden/fs/testharness:testharness',
+    '//eden/utils/test:test_lib',
   ],
   external_deps = [
     'gtest',

eden/fs/testharness/test/TestUtilTest.cpp

@@ -0,0 +1,40 @@
+/*
+ *  Copyright (c) 2016, Facebook, Inc.
+ *  All rights reserved.
+ *
+ *  This source code is licensed under the BSD-style license found in the
+ *  LICENSE file in the root directory of this source tree. An additional grant
+ *  of patent rights can be found in the PATENTS file in the same directory.
+ *
+ */
+#include "eden/fs/testharness/TestUtil.h"
+
+#include <gtest/gtest.h>
+#include "eden/fs/model/Hash.h"
+#include "eden/utils/test/TestChecks.h"
+
+using namespace facebook::eden;
+
+TEST(TestUtil, makeTestHash) {
+  EXPECT_EQ(
+      Hash{"0000000000000000000000000000000000000001"}, makeTestHash("1"));
+  EXPECT_EQ(
+      Hash{"0000000000000000000000000000000000000022"}, makeTestHash("22"));
+  EXPECT_EQ(
+      Hash{"0000000000000000000000000000000000000abc"}, makeTestHash("abc"));
+  EXPECT_EQ(
+      Hash{"123456789abcdef0fedcba9876543210faceb00c"},
+      makeTestHash("123456789abcdef0fedcba9876543210faceb00c"));
+  EXPECT_EQ(Hash{"0000000000000000000000000000000000000000"}, makeTestHash(""));
+  EXPECT_THROW_RE(
+      makeTestHash("123456789abcdef0fedcba9876543210faceb00c1"),
+      std::invalid_argument,
+      "too big");
+  EXPECT_THROW_RE(
+      makeTestHash("z"), std::exception, "could not be unhexlified");
+  EXPECT_THROW_RE(
+      // There's a "g" in the string below
+      makeTestHash("123456789abcdefgfedcba9876543210faceb00c"),
+      std::exception,
+      "could not be unhexlified");
+}