clang-tools-extra/unittests/clangd/CodeCompleteTests.cpp

//===-- CodeCompleteTests.cpp -----------------------------------*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

#include "Annotations.h"
#include "ClangdServer.h"
#include "CodeComplete.h"
#include "Compiler.h"
#include "Matchers.h"
#include "Protocol.h"
#include "SourceCode.h"
#include "SyncAPI.h"
#include "TestFS.h"
#include "index/MemIndex.h"
#include "gmock/gmock.h"
#include "gtest/gtest.h"

namespace clang {
namespace clangd {
// Let GMock print completion items and signature help.
void PrintTo(const CompletionItem &I, std::ostream *O) {
  llvm::raw_os_ostream OS(*O);
  OS << I.label << " - " << toJSON(I);
}
void PrintTo(const std::vector<CompletionItem> &V, std::ostream *O) {
  *O << "{\n";
  for (const auto &I : V) {
    *O << "\t";
    PrintTo(I, O);
    *O << "\n";
  }
  *O << "}";
}
void PrintTo(const SignatureInformation &I, std::ostream *O) {
  llvm::raw_os_ostream OS(*O);
  OS << I.label << " - " << toJSON(I);
}
void PrintTo(const std::vector<SignatureInformation> &V, std::ostream *O) {
  *O << "{\n";
  for (const auto &I : V) {
    *O << "\t";
    PrintTo(I, O);
    *O << "\n";
  }
  *O << "}";
}

namespace {
using namespace llvm;
using ::testing::AllOf;
using ::testing::Contains;
using ::testing::Each;
using ::testing::ElementsAre;
using ::testing::Not;
using ::testing::UnorderedElementsAre;
using ::testing::Field;

class IgnoreDiagnostics : public DiagnosticsConsumer {
  void onDiagnosticsReady(
      PathRef File, Tagged<std::vector<DiagWithFixIts>> Diagnostics) override {}
};

// GMock helpers for matching completion items.
MATCHER_P(Named, Name, "") { return arg.insertText == Name; }
MATCHER_P(Labeled, Label, "") { return arg.label == Label; }
MATCHER_P(Kind, K, "") { return arg.kind == K; }
MATCHER_P(Filter, F, "") { return arg.filterText == F; }
MATCHER_P(Doc, D, "") { return arg.documentation == D; }
MATCHER_P(Detail, D, "") { return arg.detail == D; }
MATCHER_P(PlainText, Text, "") {
  return arg.insertTextFormat == clangd::InsertTextFormat::PlainText &&
         arg.insertText == Text;
}
MATCHER_P(Snippet, Text, "") {
  return arg.insertTextFormat == clangd::InsertTextFormat::Snippet &&
         arg.insertText == Text;
}
MATCHER(NameContainsFilter, "") {
  if (arg.filterText.empty())
    return true;
  return llvm::StringRef(arg.insertText).contains(arg.filterText);
}
// Shorthand for Contains(Named(Name)).
Matcher<const std::vector<CompletionItem> &> Has(std::string Name) {
  return Contains(Named(std::move(Name)));
}
Matcher<const std::vector<CompletionItem> &> Has(std::string Name,
                                                 CompletionItemKind K) {
  return Contains(AllOf(Named(std::move(Name)), Kind(K)));
}
MATCHER(IsDocumented, "") { return !arg.documentation.empty(); }

std::unique_ptr<SymbolIndex> memIndex(std::vector<Symbol> Symbols) {
  SymbolSlab::Builder Slab;
  for (const auto &Sym : Symbols)
    Slab.insert(Sym);
  return MemIndex::build(std::move(Slab).build());
}

// Builds a server and runs code completion.
// If IndexSymbols is non-empty, an index will be built and passed to opts.
CompletionList completions(StringRef Text,
                           std::vector<Symbol> IndexSymbols = {},
                           clangd::CodeCompleteOptions Opts = {}) {
  std::unique_ptr<SymbolIndex> OverrideIndex;
  if (!IndexSymbols.empty()) {
    assert(!Opts.Index && "both Index and IndexSymbols given!");
    OverrideIndex = memIndex(std::move(IndexSymbols));
    Opts.Index = OverrideIndex.get();
  }

  MockFSProvider FS;
  MockCompilationDatabase CDB;
  IgnoreDiagnostics DiagConsumer;
  ClangdServer Server(CDB, DiagConsumer, FS, getDefaultAsyncThreadsCount(),
                      /*StorePreamblesInMemory=*/true);
  auto File = testPath("foo.cpp");
  Annotations Test(Text);
  Server.addDocument(File, Test.code());
  EXPECT_TRUE(Server.blockUntilIdleForTest()) << "Waiting for preamble";
  auto CompletionList = runCodeComplete(Server, File, Test.point(), Opts).Value;
  // Sanity-check that filterText is valid.
  EXPECT_THAT(CompletionList.items, Each(NameContainsFilter()));
  return CompletionList;
}

std::string replace(StringRef Haystack, StringRef Needle, StringRef Repl) {
  std::string Result;
  raw_string_ostream OS(Result);
  std::pair<StringRef, StringRef> Split;
  for (Split = Haystack.split(Needle); !Split.second.empty();
       Split = Split.first.split(Needle))
    OS << Split.first << Repl;
  Result += Split.first;
  OS.flush();
  return Result;
}

// Helpers to produce fake index symbols for memIndex() or completions().
// USRFormat is a regex replacement string for the unqualified part of the USR.
Symbol sym(StringRef QName, index::SymbolKind Kind, StringRef USRFormat) {
  Symbol Sym;
  std::string USR = "c:"; // We synthesize a few simple cases of USRs by hand!
  size_t Pos = QName.rfind("::");
  if (Pos == llvm::StringRef::npos) {
    Sym.Name = QName;
    Sym.Scope = "";
  } else {
    Sym.Name = QName.substr(Pos + 2);
    Sym.Scope = QName.substr(0, Pos + 2);
    USR += "@N@" + replace(QName.substr(0, Pos), "::", "@N@"); // ns:: -> @N@ns
  }
  USR += Regex("^.*$").sub(USRFormat, Sym.Name); // e.g. func -> @F@func#
  Sym.ID = SymbolID(USR);
  Sym.CompletionPlainInsertText = Sym.Name;
  Sym.CompletionSnippetInsertText = Sym.Name;
  Sym.CompletionLabel = Sym.Name;
  Sym.SymInfo.Kind = Kind;
  return Sym;
}
Symbol func(StringRef Name) { // Assumes the function has no args.
  return sym(Name, index::SymbolKind::Function, "@F@\\0#"); // no args
}
Symbol cls(StringRef Name) {
  return sym(Name, index::SymbolKind::Class, "@S@\\0@S@\\0");
}
Symbol var(StringRef Name) {
  return sym(Name, index::SymbolKind::Variable, "@\\0");
}

TEST(CompletionTest, Limit) {
  clangd::CodeCompleteOptions Opts;
  Opts.Limit = 2;
  auto Results = completions(R"cpp(
struct ClassWithMembers {
  int AAA();
  int BBB();
  int CCC();
}
int main() { ClassWithMembers().^ }
      )cpp",
                             /*IndexSymbols=*/{}, Opts);

  EXPECT_TRUE(Results.isIncomplete);
  EXPECT_THAT(Results.items, ElementsAre(Named("AAA"), Named("BBB")));
}

TEST(CompletionTest, Filter) {
  std::string Body = R"cpp(
    int Abracadabra;
    int Alakazam;
    struct S {
      int FooBar;
      int FooBaz;
      int Qux;
    };
  )cpp";
  EXPECT_THAT(completions(Body + "int main() { S().Foba^ }").items,
              AllOf(Has("FooBar"), Has("FooBaz"), Not(Has("Qux"))));

  EXPECT_THAT(completions(Body + "int main() { S().FR^ }").items,
              AllOf(Has("FooBar"), Not(Has("FooBaz")), Not(Has("Qux"))));

  EXPECT_THAT(completions(Body + "int main() { S().opr^ }").items,
              Has("operator="));

  EXPECT_THAT(completions(Body + "int main() { aaa^ }").items,
              AllOf(Has("Abracadabra"), Has("Alakazam")));

  EXPECT_THAT(completions(Body + "int main() { _a^ }").items,
              AllOf(Has("static_cast"), Not(Has("Abracadabra"))));
}

void TestAfterDotCompletion(clangd::CodeCompleteOptions Opts) {
  auto Results = completions(
      R"cpp(
      #define MACRO X

      int global_var;

      int global_func();

      struct GlobalClass {};

      struct ClassWithMembers {
        /// Doc for method.
        int method();

        int field;
      private:
        int private_field;
      };

      int test() {
        struct LocalClass {};

        /// Doc for local_var.
        int local_var;

        ClassWithMembers().^
      }
      )cpp",
      {cls("IndexClass"), var("index_var"), func("index_func")}, Opts);

  // Class members. The only items that must be present in after-dot
  // completion.
  EXPECT_THAT(
      Results.items,
      AllOf(Has(Opts.EnableSnippets ? "method()" : "method"), Has("field")));
  EXPECT_IFF(Opts.IncludeIneligibleResults, Results.items,
             Has("private_field"));
  // Global items.
  EXPECT_THAT(
      Results.items,
      Not(AnyOf(Has("global_var"), Has("index_var"), Has("global_func"),
                Has("global_func()"), Has("index_func"), Has("GlobalClass"),
                Has("IndexClass"), Has("MACRO"), Has("LocalClass"))));
  // There should be no code patterns (aka snippets) in after-dot
  // completion. At least there aren't any we're aware of.
  EXPECT_THAT(Results.items, Not(Contains(Kind(CompletionItemKind::Snippet))));
  // Check documentation.
  EXPECT_IFF(Opts.IncludeBriefComments, Results.items,
             Contains(IsDocumented()));
}

void TestGlobalScopeCompletion(clangd::CodeCompleteOptions Opts) {
  auto Results = completions(
      R"cpp(
      #define MACRO X

      int global_var;
      int global_func();

      struct GlobalClass {};

      struct ClassWithMembers {
        /// Doc for method.
        int method();
      };

      int test() {
        struct LocalClass {};

        /// Doc for local_var.
        int local_var;

        ^
      }
      )cpp",
      {cls("IndexClass"), var("index_var"), func("index_func")}, Opts);

  // Class members. Should never be present in global completions.
  EXPECT_THAT(Results.items,
              Not(AnyOf(Has("method"), Has("method()"), Has("field"))));
  // Global items.
  EXPECT_THAT(Results.items,
              AllOf(Has("global_var"), Has("index_var"),
                    Has(Opts.EnableSnippets ? "global_func()" : "global_func"),
                    Has("index_func" /* our fake symbol doesn't include () */),
                    Has("GlobalClass"), Has("IndexClass")));
  // A macro.
  EXPECT_IFF(Opts.IncludeMacros, Results.items, Has("MACRO"));
  // Local items. Must be present always.
  EXPECT_THAT(Results.items,
              AllOf(Has("local_var"), Has("LocalClass"),
                    Contains(Kind(CompletionItemKind::Snippet))));
  // Check documentation.
  EXPECT_IFF(Opts.IncludeBriefComments, Results.items,
             Contains(IsDocumented()));
}

TEST(CompletionTest, CompletionOptions) {
  auto Test = [&](const clangd::CodeCompleteOptions &Opts) {
    TestAfterDotCompletion(Opts);
    TestGlobalScopeCompletion(Opts);
  };
  // We used to test every combination of options, but that got too slow (2^N).
  auto Flags = {
    &clangd::CodeCompleteOptions::IncludeMacros,
    &clangd::CodeCompleteOptions::IncludeBriefComments,
    &clangd::CodeCompleteOptions::EnableSnippets,
    &clangd::CodeCompleteOptions::IncludeCodePatterns,
    &clangd::CodeCompleteOptions::IncludeIneligibleResults,
  };
  // Test default options.
  Test({});
  // Test with one flag flipped.
  for (auto &F : Flags) {
    clangd::CodeCompleteOptions O;
    O.*F ^= true;
    Test(O);
  }
}

// Check code completion works when the file contents are overridden.
TEST(CompletionTest, CheckContentsOverride) {
  MockFSProvider FS;
  IgnoreDiagnostics DiagConsumer;
  MockCompilationDatabase CDB;
  ClangdServer Server(CDB, DiagConsumer, FS, getDefaultAsyncThreadsCount(),
                      /*StorePreamblesInMemory=*/true);
  auto File = testPath("foo.cpp");
  Server.addDocument(File, "ignored text!");

  Annotations Example("int cbc; int b = ^;");
  auto Results =
      runCodeComplete(Server, File, Example.point(),
                      clangd::CodeCompleteOptions(), StringRef(Example.code()))
          .Value;
  EXPECT_THAT(Results.items, Contains(Named("cbc")));
}

TEST(CompletionTest, Priorities) {
  auto Internal = completions(R"cpp(
      class Foo {
        public: void pub();
        protected: void prot();
        private: void priv();
      };
      void Foo::pub() { this->^ }
  )cpp");
  EXPECT_THAT(Internal.items,
              HasSubsequence(Named("priv"), Named("prot"), Named("pub")));

  auto External = completions(R"cpp(
      class Foo {
        public: void pub();
        protected: void prot();
        private: void priv();
      };
      void test() {
        Foo F;
        F.^
      }
  )cpp");
  EXPECT_THAT(External.items,
              AllOf(Has("pub"), Not(Has("prot")), Not(Has("priv"))));
}

TEST(CompletionTest, Qualifiers) {
  auto Results = completions(R"cpp(
      class Foo {
        public: int foo() const;
        int bar() const;
      };
      class Bar : public Foo {
        int foo() const;
      };
      void test() { Bar().^ }
  )cpp");
  EXPECT_THAT(Results.items, HasSubsequence(Labeled("bar() const"),
                                            Labeled("Foo::foo() const")));
  EXPECT_THAT(Results.items, Not(Contains(Labeled("foo() const")))); // private
}

TEST(CompletionTest, Snippets) {
  clangd::CodeCompleteOptions Opts;
  Opts.EnableSnippets = true;
  auto Results = completions(
      R"cpp(
      struct fake {
        int a;
        int f(int i, const float f) const;
      };
      int main() {
        fake f;
        f.^
      }
      )cpp",
      /*IndexSymbols=*/{}, Opts);
  EXPECT_THAT(Results.items,
              HasSubsequence(Snippet("a"),
                             Snippet("f(${1:int i}, ${2:const float f})")));
}

TEST(CompletionTest, Kinds) {
  auto Results = completions(
      R"cpp(
          #define MACRO X
          int variable;
          struct Struct {};
          int function();
          int X = ^
      )cpp",
      {func("indexFunction"), var("indexVariable"), cls("indexClass")});
  EXPECT_THAT(Results.items,
              AllOf(Has("function", CompletionItemKind::Function),
                    Has("variable", CompletionItemKind::Variable),
                    Has("int", CompletionItemKind::Keyword),
                    Has("Struct", CompletionItemKind::Class),
                    Has("MACRO", CompletionItemKind::Text),
                    Has("indexFunction", CompletionItemKind::Function),
                    Has("indexVariable", CompletionItemKind::Variable),
                    Has("indexClass", CompletionItemKind::Class)));

  Results = completions("nam^");
  EXPECT_THAT(Results.items, Has("namespace", CompletionItemKind::Snippet));
}

TEST(CompletionTest, NoDuplicates) {
  auto Results = completions(
      R"cpp(
          class Adapter {
            void method();
          };

          void Adapter::method() {
            Adapter^
          }
      )cpp",
      {cls("Adapter")});

  // Make sure there are no duplicate entries of 'Adapter'.
  EXPECT_THAT(Results.items, ElementsAre(Named("Adapter")));
}

TEST(CompletionTest, ScopedNoIndex) {
  auto Results = completions(
      R"cpp(
          namespace fake { int BigBang, Babble, Ball; };
          int main() { fake::bb^ }
      ")cpp");
  // BigBang is a better match than Babble. Ball doesn't match at all.
  EXPECT_THAT(Results.items, ElementsAre(Named("BigBang"), Named("Babble")));
}

TEST(CompletionTest, Scoped) {
  auto Results = completions(
      R"cpp(
          namespace fake { int Babble, Ball; };
          int main() { fake::bb^ }
      ")cpp",
      {var("fake::BigBang")});
  EXPECT_THAT(Results.items, ElementsAre(Named("BigBang"), Named("Babble")));
}

TEST(CompletionTest, ScopedWithFilter) {
  auto Results = completions(
      R"cpp(
          void f() { ns::x^ }
      )cpp",
      {cls("ns::XYZ"), func("ns::foo")});
  EXPECT_THAT(Results.items,
              UnorderedElementsAre(AllOf(Named("XYZ"), Filter("XYZ"))));
}

TEST(CompletionTest, GlobalQualified) {
  auto Results = completions(
      R"cpp(
          void f() { ::^ }
      )cpp",
      {cls("XYZ")});
  EXPECT_THAT(Results.items, AllOf(Has("XYZ", CompletionItemKind::Class),
                                   Has("f", CompletionItemKind::Function)));
}

TEST(CompletionTest, FullyQualified) {
  auto Results = completions(
      R"cpp(
          namespace ns { void bar(); }
          void f() { ::ns::^ }
      )cpp",
      {cls("ns::XYZ")});
  EXPECT_THAT(Results.items, AllOf(Has("XYZ", CompletionItemKind::Class),
                                   Has("bar", CompletionItemKind::Function)));
}

TEST(CompletionTest, SemaIndexMerge) {
  auto Results = completions(
      R"cpp(
          namespace ns { int local; void both(); }
          void f() { ::ns::^ }
      )cpp",
      {func("ns::both"), cls("ns::Index")});
  // We get results from both index and sema, with no duplicates.
  EXPECT_THAT(
      Results.items,
      UnorderedElementsAre(Named("local"), Named("Index"), Named("both")));
}

TEST(CompletionTest, SemaIndexMergeWithLimit) {
  clangd::CodeCompleteOptions Opts;
  Opts.Limit = 1;
  auto Results = completions(
      R"cpp(
          namespace ns { int local; void both(); }
          void f() { ::ns::^ }
      )cpp",
      {func("ns::both"), cls("ns::Index")}, Opts);
  EXPECT_EQ(Results.items.size(), Opts.Limit);
  EXPECT_TRUE(Results.isIncomplete);
}

TEST(CompletionTest, IndexSuppressesPreambleCompletions) {
  MockFSProvider FS;
  MockCompilationDatabase CDB;
  IgnoreDiagnostics DiagConsumer;
  ClangdServer Server(CDB, DiagConsumer, FS, getDefaultAsyncThreadsCount(),
                      /*StorePreamblesInMemory=*/true);

  FS.Files[testPath("bar.h")] =
      R"cpp(namespace ns { struct preamble { int member; }; })cpp";
  auto File = testPath("foo.cpp");
  Annotations Test(R"cpp(
      #include "bar.h"
      namespace ns { int local; }
      void f() { ns::^; }
      void f() { ns::preamble().$2^; }
  )cpp");
  Server.addDocument(File, Test.code());
  ASSERT_TRUE(Server.blockUntilIdleForTest()) << "Waiting for preamble";
  clangd::CodeCompleteOptions Opts = {};

  auto I = memIndex({var("ns::index")});
  Opts.Index = I.get();
  auto WithIndex = runCodeComplete(Server, File, Test.point(), Opts).Value;
  EXPECT_THAT(WithIndex.items,
              UnorderedElementsAre(Named("local"), Named("index")));
  auto ClassFromPreamble =
      runCodeComplete(Server, File, Test.point("2"), Opts).Value;
  EXPECT_THAT(ClassFromPreamble.items, Contains(Named("member")));

  Opts.Index = nullptr;
  auto WithoutIndex = runCodeComplete(Server, File, Test.point(), Opts).Value;
  EXPECT_THAT(WithoutIndex.items,
              UnorderedElementsAre(Named("local"), Named("preamble")));

}

TEST(CompletionTest, DynamicIndexMultiFile) {
  MockFSProvider FS;
  MockCompilationDatabase CDB;
  IgnoreDiagnostics DiagConsumer;
  ClangdServer Server(CDB, DiagConsumer, FS, getDefaultAsyncThreadsCount(),
                      /*StorePreamblesInMemory=*/true,
                      /*BuildDynamicSymbolIndex=*/true);

  FS.Files[testPath("foo.h")] = R"cpp(
      namespace ns { class XYZ {}; void foo(int x) {} }
  )cpp";
  Server.addDocument(testPath("foo.cpp"), R"cpp(
      #include "foo.h"
  )cpp");
  ASSERT_TRUE(Server.blockUntilIdleForTest()) << "Waiting for preamble";

  auto File = testPath("bar.cpp");
  Annotations Test(R"cpp(
      namespace ns {
      class XXX {};
      /// Doooc
      void fooooo() {}
      }
      void f() { ns::^ }
  )cpp");
  Server.addDocument(File, Test.code());
  ASSERT_TRUE(Server.blockUntilIdleForTest()) << "Waiting for preamble";

  auto Results = runCodeComplete(Server, File, Test.point(), {}).Value;
  // "XYZ" and "foo" are not included in the file being completed but are still
  // visible through the index.
  EXPECT_THAT(Results.items, Has("XYZ", CompletionItemKind::Class));
  EXPECT_THAT(Results.items, Has("foo", CompletionItemKind::Function));
  EXPECT_THAT(Results.items, Has("XXX", CompletionItemKind::Class));
  EXPECT_THAT(Results.items, Contains(AllOf(Named("fooooo"), Filter("fooooo"),
                                            Kind(CompletionItemKind::Function),
                                            Doc("Doooc"), Detail("void"))));
}

TEST(CodeCompleteTest, DisableTypoCorrection) {
  auto Results = completions(R"cpp(
     namespace clang { int v; }
     void f() { clangd::^
  )cpp");
  EXPECT_TRUE(Results.items.empty());
}

SignatureHelp signatures(StringRef Text) {
  MockFSProvider FS;
  MockCompilationDatabase CDB;
  IgnoreDiagnostics DiagConsumer;
  ClangdServer Server(CDB, DiagConsumer, FS, getDefaultAsyncThreadsCount(),
                      /*StorePreamblesInMemory=*/true);
  auto File = testPath("foo.cpp");
  Annotations Test(Text);
  Server.addDocument(File, Test.code());
  EXPECT_TRUE(Server.blockUntilIdleForTest()) << "Waiting for preamble";
  auto R = runSignatureHelp(Server, File, Test.point());
  assert(R);
  return R.get().Value;
}

MATCHER_P(ParamsAre, P, "") {
  if (P.size() != arg.parameters.size())
    return false;
  for (unsigned I = 0; I < P.size(); ++I)
    if (P[I] != arg.parameters[I].label)
      return false;
  return true;
}

Matcher<SignatureInformation> Sig(std::string Label,
                                  std::vector<std::string> Params) {
  return AllOf(Labeled(Label), ParamsAre(Params));
}

TEST(SignatureHelpTest, Overloads) {
  auto Results = signatures(R"cpp(
    void foo(int x, int y);
    void foo(int x, float y);
    void foo(float x, int y);
    void foo(float x, float y);
    void bar(int x, int y = 0);
    int main() { foo(^); }
  )cpp");
  EXPECT_THAT(Results.signatures,
              UnorderedElementsAre(
                  Sig("foo(float x, float y) -> void", {"float x", "float y"}),
                  Sig("foo(float x, int y) -> void", {"float x", "int y"}),
                  Sig("foo(int x, float y) -> void", {"int x", "float y"}),
                  Sig("foo(int x, int y) -> void", {"int x", "int y"})));
  // We always prefer the first signature.
  EXPECT_EQ(0, Results.activeSignature);
  EXPECT_EQ(0, Results.activeParameter);
}

TEST(SignatureHelpTest, DefaultArgs) {
  auto Results = signatures(R"cpp(
    void bar(int x, int y = 0);
    void bar(float x = 0, int y = 42);
    int main() { bar(^
  )cpp");
  EXPECT_THAT(Results.signatures,
              UnorderedElementsAre(
                  Sig("bar(int x, int y = 0) -> void", {"int x", "int y = 0"}),
                  Sig("bar(float x = 0, int y = 42) -> void",
                      {"float x = 0", "int y = 42"})));
  EXPECT_EQ(0, Results.activeSignature);
  EXPECT_EQ(0, Results.activeParameter);
}

TEST(SignatureHelpTest, ActiveArg) {
  auto Results = signatures(R"cpp(
    int baz(int a, int b, int c);
    int main() { baz(baz(1,2,3), ^); }
  )cpp");
  EXPECT_THAT(Results.signatures,
              ElementsAre(Sig("baz(int a, int b, int c) -> int",
                              {"int a", "int b", "int c"})));
  EXPECT_EQ(0, Results.activeSignature);
  EXPECT_EQ(1, Results.activeParameter);
}

class IndexRequestCollector : public SymbolIndex {
public:
  bool
  fuzzyFind(const FuzzyFindRequest &Req,
            llvm::function_ref<void(const Symbol &)> Callback) const override {
    Requests.push_back(Req);
    return true;
  }

  const std::vector<FuzzyFindRequest> allRequests() const { return Requests; }

private:
  mutable std::vector<FuzzyFindRequest> Requests;
};

std::vector<FuzzyFindRequest> captureIndexRequests(llvm::StringRef Code) {
  clangd::CodeCompleteOptions Opts;
  IndexRequestCollector Requests;
  Opts.Index = &Requests;
  completions(Code, {}, Opts);
  return Requests.allRequests();
}

TEST(CompletionTest, UnqualifiedIdQuery) {
  auto Requests = captureIndexRequests(R"cpp(
      namespace std {}
      using namespace std;
      namespace ns {
      void f() {
        vec^
      }
      }
  )cpp");

  EXPECT_THAT(Requests,
              ElementsAre(Field(&FuzzyFindRequest::Scopes,
                                UnorderedElementsAre("", "ns::", "std::"))));
}

TEST(CompletionTest, ResolvedQualifiedIdQuery) {
  auto Requests = captureIndexRequests(R"cpp(
      namespace ns1 {}
      namespace ns2 {} // ignore
      namespace ns3 { namespace nns3 {} }
      namespace foo {
      using namespace ns1;
      using namespace ns3::nns3;
      }
      namespace ns {
      void f() {
        foo::^
      }
      }
  )cpp");

  EXPECT_THAT(Requests,
              ElementsAre(Field(
                  &FuzzyFindRequest::Scopes,
                  UnorderedElementsAre("foo::", "ns1::", "ns3::nns3::"))));
}

TEST(CompletionTest, UnresolvedQualifierIdQuery) {
  auto Requests = captureIndexRequests(R"cpp(
      namespace a {}
      using namespace a;
      namespace ns {
      void f() {
      bar::^
      }
      } // namespace ns
  )cpp");

  EXPECT_THAT(Requests, ElementsAre(Field(&FuzzyFindRequest::Scopes,
                                          UnorderedElementsAre("bar::"))));
}

TEST(CompletionTest, UnresolvedNestedQualifierIdQuery) {
  auto Requests = captureIndexRequests(R"cpp(
      namespace a {}
      using namespace a;
      namespace ns {
      void f() {
      ::a::bar::^
      }
      } // namespace ns
  )cpp");

  EXPECT_THAT(Requests, ElementsAre(Field(&FuzzyFindRequest::Scopes,
                                          UnorderedElementsAre("a::bar::"))));
}

TEST(CompletionTest, EmptyQualifiedQuery) {
  auto Requests = captureIndexRequests(R"cpp(
      namespace ns {
      void f() {
      ^
      }
      } // namespace ns
  )cpp");

  EXPECT_THAT(Requests, ElementsAre(Field(&FuzzyFindRequest::Scopes,
                                          UnorderedElementsAre("", "ns::"))));
}

TEST(CompletionTest, GlobalQualifiedQuery) {
  auto Requests = captureIndexRequests(R"cpp(
      namespace ns {
      void f() {
      ::^
      }
      } // namespace ns
  )cpp");

  EXPECT_THAT(Requests, ElementsAre(Field(&FuzzyFindRequest::Scopes,
                                          UnorderedElementsAre(""))));
}

} // namespace
} // namespace clangd
} // namespace clang