1 files changed, 169 insertions, 0 deletions
diff --git a/clang-tools-extra/clangd/unittests/HeaderSourceSwitchTests.cpp b/clang-tools-extra/clangd/unittests/HeaderSourceSwitchTests.cpp
index 6835fdfd0f4..1ca543d5764 100644
--- a/clang-tools-extra/clangd/unittests/HeaderSourceSwitchTests.cpp
+++ b/clang-tools-extra/clangd/unittests/HeaderSourceSwitchTests.cpp
@@ -10,6 +10,7 @@
 
 #include "TestFS.h"
 #include "TestTU.h"
+#include "index/MemIndex.h"
 #include "gmock/gmock.h"
 #include "gtest/gtest.h"
 
@@ -71,6 +72,174 @@ TEST(HeaderSourceSwitchTest, FileHeuristic) {
   EXPECT_FALSE(PathResult.hasValue());
 }
 
+MATCHER_P(DeclNamed, Name, "") {
+  if (const NamedDecl *ND = dyn_cast<NamedDecl>(arg))
+    if (ND->getQualifiedNameAsString() == Name)
+      return true;
+  return false;
+}
+
+TEST(HeaderSourceSwitchTest, GetLocalDecls) {
+  TestTU TU;
+  TU.HeaderCode = R"cpp(
+  void HeaderOnly();
+  )cpp";
+  TU.Code = R"cpp(
+  void MainF1();
+  class Foo {};
+  namespace ns {
+  class Foo {
+    void method();
+    int field;
+  };
+  } // namespace ns
+
+  // Non-indexable symbols
+  namespace {
+  void Ignore1() {}
+  }
+
+  )cpp";
+
+  auto AST = TU.build();
+  EXPECT_THAT(getIndexableLocalDecls(AST),
+              testing::UnorderedElementsAre(
+                  DeclNamed("MainF1"), DeclNamed("Foo"), DeclNamed("ns::Foo"),
+                  DeclNamed("ns::Foo::method"), DeclNamed("ns::Foo::field")));
+}
+
+TEST(HeaderSourceSwitchTest, FromHeaderToSource) {
+  // build a proper index, which contains symbols:
+  //   A_Sym1, declared in TestTU.h, defined in a.cpp
+  //   B_Sym[1-2], declared in TestTU.h, defined in b.cpp
+  SymbolSlab::Builder AllSymbols;
+  TestTU Testing;
+  Testing.HeaderFilename = "TestTU.h";
+  Testing.HeaderCode = "void A_Sym1();";
+  Testing.Filename = "a.cpp";
+  Testing.Code = "void A_Sym1() {};";
+  for (auto &Sym : Testing.headerSymbols())
+    AllSymbols.insert(Sym);
+
+  Testing.HeaderCode = R"cpp(
+  void B_Sym1();
+  void B_Sym2();
+  )cpp";
+  Testing.Filename = "b.cpp";
+  Testing.Code = R"cpp(
+  void B_Sym1() {}
+  void B_Sym2() {}
+  )cpp";
+  for (auto &Sym : Testing.headerSymbols())
+    AllSymbols.insert(Sym);
+  auto Index = MemIndex::build(std::move(AllSymbols).build(), {}, {});
+
+  // Test for swtich from .h header to .cc source
+  struct {
+    llvm::StringRef HeaderCode;
+    llvm::Optional<std::string> ExpectedSource;
+  } TestCases[] = {
+      {"// empty, no header found", llvm::None},
+      {R"cpp(
+         // no definition found in the index.
+         void NonDefinition();
+       )cpp",
+       llvm::None},
+      {R"cpp(
+         void A_Sym1();
+       )cpp",
+       testPath("a.cpp")},
+      {R"cpp(
+         // b.cpp wins.
+         void A_Sym1();
+         void B_Sym1();
+         void B_Sym2();
+       )cpp",
+       testPath("b.cpp")},
+      {R"cpp(
+         // a.cpp and b.cpp have same scope, but a.cpp because "a.cpp" < "b.cpp".
+         void A_Sym1();
+         void B_Sym1();
+       )cpp",
+       testPath("a.cpp")},
+  };
+  for (const auto &Case : TestCases) {
+    TestTU TU = TestTU::withCode(Case.HeaderCode);
+    TU.Filename = "TestTU.h";
+    TU.ExtraArgs.push_back("-xc++-header"); // inform clang this is a header.
+    auto HeaderAST = TU.build();
+    EXPECT_EQ(Case.ExpectedSource,
+              getCorrespondingHeaderOrSource(testPath(TU.Filename), HeaderAST,
+                                             Index.get()));
+  }
+}
+
+TEST(HeaderSourceSwitchTest, FromSourceToHeader) {
+  // build a proper index, which contains symbols:
+  //   A_Sym1, declared in a.h, defined in TestTU.cpp
+  //   B_Sym[1-2], declared in b.h, defined in TestTU.cpp
+  TestTU TUForIndex = TestTU::withCode(R"cpp(
+  #include "a.h"
+  #include "b.h"
+
+  void A_Sym1() {}
+
+  void B_Sym1() {}
+  void B_Sym2() {}
+  )cpp");
+  TUForIndex.AdditionalFiles["a.h"] = R"cpp(
+  void A_Sym1();
+  )cpp";
+  TUForIndex.AdditionalFiles["b.h"] = R"cpp(
+  void B_Sym1();
+  void B_Sym2();
+  )cpp";
+  TUForIndex.Filename = "TestTU.cpp";
+  auto Index = TUForIndex.index();
+
+  // Test for switching from .cc source file to .h header.
+  struct {
+    llvm::StringRef SourceCode;
+    llvm::Optional<std::string> ExpectedResult;
+  } TestCases[] = {
+      {"// empty, no header found", llvm::None},
+      {R"cpp(
+         // symbol not in index, no header found
+         void Local() {}
+       )cpp",
+       llvm::None},
+
+      {R"cpp(
+         // a.h wins.
+         void A_Sym1() {}
+       )cpp",
+       testPath("a.h")},
+
+      {R"cpp(
+         // b.h wins.
+         void A_Sym1() {}
+         void B_Sym1() {}
+         void B_Sym2() {}
+       )cpp",
+       testPath("b.h")},
+
+      {R"cpp(
+         // a.h and b.h have same scope, but a.h wins because "a.h" < "b.h".
+         void A_Sym1() {}
+         void B_Sym1() {}
+       )cpp",
+       testPath("a.h")},
+  };
+  for (const auto &Case : TestCases) {
+    TestTU TU = TestTU::withCode(Case.SourceCode);
+    TU.Filename = "Test.cpp";
+    auto AST = TU.build();
+    EXPECT_EQ(Case.ExpectedResult,
+              getCorrespondingHeaderOrSource(testPath(TU.Filename), AST,
+                                             Index.get()));
+  }
+}
+
 } // namespace
 } // namespace clangd
 } // namespace clang