[JSONSerialization] Add basic unit tests for JSONSerialization

Author: rintaro

unittests/Basic/CMakeLists.txt

@@ -15,6 +15,7 @@ add_swift_unittest(SwiftBasicTests
   EncodedSequenceTest.cpp
   FileSystemTest.cpp
   ImmutablePointerSetTest.cpp
+  JSONSerialization.cpp
   OptionSetTest.cpp
   OwnedStringTest.cpp
   PointerIntEnumTest.cpp

unittests/Basic/JSONSerialization.cpp

@@ -0,0 +1,123 @@
+//===--- CacheTest.cpp ----------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2018 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+#include "swift/Basic/JSONSerialization.h"
+#include "gtest/gtest.h"
+
+namespace {
+struct Leaf {
+  int Val;
+};
+
+struct Root {
+  std::string Name;
+  std::vector<Leaf *> Children;
+  std::vector<Leaf *> Empty;
+  Leaf *Side;
+};
+} // namespace
+
+namespace swift {
+namespace json {
+
+template <> struct ObjectTraits<Leaf> {
+  static void mapping(Output &out, Leaf &value) {
+    switch (value.Val) {
+    case 0:
+      break;
+    case 1:
+      out.mapRequired("Value", value.Val);
+      break;
+    case 2: {
+      std::string two("two");
+      out.mapRequired("Value", two);
+      break;
+    }
+    default:
+      break;
+    }
+  }
+};
+
+template <> struct NullableTraits<Leaf *> {
+  static bool isNull(Leaf *&value) { return !value; }
+  static Leaf &get(Leaf *&value) { return *value; }
+};
+
+template <> struct ArrayTraits<std::vector<Leaf *>> {
+
+  using value_type = Leaf *;
+
+  static size_t size(Output &out, std::vector<Leaf *> &seq) {
+    return seq.size();
+  }
+  static Leaf *&element(Output &out, std::vector<Leaf *> &seq, size_t index) {
+    return seq[index];
+  }
+};
+
+template <> struct ObjectTraits<Root> {
+  static void mapping(Output &out, Root &value) {
+    out.mapRequired("Name", value.Name);
+    out.mapRequired("Children", value.Children);
+    out.mapRequired("Empty", value.Empty);
+    out.mapRequired("Side", value.Side);
+  }
+};
+
+} // namespace json
+} // namespace swift
+
+TEST(JSONSerialization, basicCompact) {
+  Leaf LeafObj0{0};
+  Leaf LeafObj1{1};
+  Leaf LeafObj2{2};
+  Root RootObj{"foo", {&LeafObj0, &LeafObj1, nullptr, &LeafObj2}, {}, nullptr};
+  std::string Buffer;
+  llvm::raw_string_ostream Stream(Buffer);
+  swift::json::Output Out(Stream, /*PrettyPrint=*/false);
+
+  Out << RootObj;
+  Stream.flush();
+
+  EXPECT_EQ(Buffer, "{\"Name\":\"foo\",\"Children\":[{},{\"Value\":1},null,{"
+                    "\"Value\":\"two\"}],\"Empty\":[],\"Side\":null}");
+}
+
+TEST(JSONSerialization, basicPretty) {
+  Leaf LeafObj0{0};
+  Leaf LeafObj1{1};
+  Leaf LeafObj2{2};
+  Root RootObj{"foo", {&LeafObj0, &LeafObj1, nullptr, &LeafObj2}, {}, nullptr};
+  std::string Buffer;
+  llvm::raw_string_ostream Stream(Buffer);
+  swift::json::Output Out(Stream);
+
+  Out << RootObj;
+  Stream.flush();
+
+  EXPECT_EQ(Buffer, R"""({
+  "Name": "foo",
+  "Children": [
+    {},
+    {
+      "Value": 1
+    },
+    null,
+    {
+      "Value": "two"
+    }
+  ],
+  "Empty": [],
+  "Side": null
+})""");
+}