[clangd] Convert lit code completion tests to unit-tests. NFC

[sammccall]

Summary

This improves readability of tests and error messages.

[ilya-biryukov]

LGTM

unittests/clangd/CodeCompleteTests.cpp

289

The ^ symbol conflicts with the corresponding operator.
Even though it's not widely used, I'm wondering whether we should use a different marker for completion position.

335

The formatting is a bit weird. Is this a clang-format bug?

[ioeric]

lg

unittests/clangd/Matchers.h

54

override?

77

It would be helpful to provide a bit documentation here.

[sammccall]

Reformat around code-complete testcases

[sammccall]

Add documentation to matcher implementation.

[sammccall]

unittests/clangd/CodeCompleteTests.cpp

289

Almost all characters conflict with something in C++ :-(
^ is rarely going to cause problems and is suggestive of an insertion point.

The failure modes here don't seem worth worrying about:

• we add a test that needs to use ^. The assert fires, it's easy to tell what happened, and we have to add escaping or change the notation. Annoying, but easy to detect and pretty unlikely.
• we add a test that needs to use exactly one ^, *and* we forget to add the cursor marker to the test. The assert doesn't fire, the test fails in some random way. This is really annoying, but also vanishingly unlikely.

(I'd feel differently if this wasn't just a local test helper of course)

335

Weird formatting is a clang-format *feature*.
I reformatted all the tests, now they're weird in a different way.

test/clangd/completion-items-kinds.test

-# RUN: clangd -enable-snippets -run-synchronously < %s | FileCheck %s
-# It is absolutely vital that this file has CRLF line endings.
-#
-Content-Length: 125
-
-{"jsonrpc":"2.0","id":0,"method":"initialize","params":{"processId":123,"rootPath":"clangd","capabilities":{},"trace":"off"}}
-Content-Length: 220
-
-{"jsonrpc":"2.0","method":"textDocument/didOpen","params":{"textDocument":{"uri":"file:///main.cpp","languageId":"cpp","version":1,"text":"#define MACRO X\nint variable;\nstruct Struct {};\n int function();\nint X = "}}}
-Content-Length: 148
-
-{"jsonrpc":"2.0","id":1,"method":"textDocument/completion","params":{"textDocument":{"uri":"file:///main.cpp"},"position":{"line":4,"character":7}}}
-# CHECK: {"id":1,"jsonrpc":"2.0","result":{"isIncomplete":false,"items":
-#
-# Function
-# CHECK: {"detail":"int","filterText":"function","insertText":"function()","insertTextFormat":1,"kind":3,"label":"function()","sortText":"{{.*}}function"}
-#
-# Variable
-# CHECK: {"detail":"int","filterText":"variable","insertText":"variable","insertTextFormat":1,"kind":6,"label":"variable","sortText":"{{.*}}variable"}
-#
-# Keyword
-# CHECK: {"filterText":"int","insertText":"int","insertTextFormat":1,"kind":14,"label":"int","sortText":"{{.*}}int"}
-#
-# Struct
-# CHECK: {"filterText":"Struct","insertText":"Struct","insertTextFormat":1,"kind":7,"label":"Struct","sortText":"{{.*}}Struct"}
-#
-# Macro
-# CHECK: {"filterText":"MACRO","insertText":"MACRO","insertTextFormat":1,"kind":1,"label":"MACRO","sortText":"{{.*}}MACRO"}
-#
-# CHECK-SAME: ]}}
-Content-Length: 146
-
-{"jsonrpc":"2.0","method":"textDocument/didOpen","params":{"textDocument":{"uri":"file:///main.cpp","languageId":"cpp","version":1,"text":"nam"}}}
-Content-Length: 148
-
-{"jsonrpc":"2.0","id":2,"method":"textDocument/completion","params":{"textDocument":{"uri":"file:///main.cpp"},"position":{"line":1,"character":3}}}
-# Code pattern (unfortunately there are none in expression context)
-# CHECK-DAG: {"filterText":"namespace","insertText":"namespace ${1:identifier}{${2:declarations}\n}","insertTextFormat":2,"kind":15,"label":"namespace identifier{declarations}","sortText":"{{.*}}namespace"}
-#
-Content-Length: 58
-
-{"jsonrpc":"2.0","id":3,"method":"shutdown","params":null}

test/clangd/completion-priorities.test

-# RUN: clangd -pretty -run-synchronously < %s | FileCheck -strict-whitespace %s
-# It is absolutely vital that this file has CRLF line endings.
-#
-
-Content-Length: 127
-
-{"jsonrpc":"2.0","id":0,"method":"initialize","params":{"processId":123,"rootPath":"clangd","capabilities":{},"trace":"off"}}
-
-Content-Length: 312
-
-{"jsonrpc":"2.0","method":"textDocument/didOpen","params":{"textDocument":{"uri":"file:///main.cpp","languageId":"cpp","version":1,"text":"class Foo {\npublic:\n  void pub();\n\nprotected:\n  void prot();\n\nprivate:\n  void priv();\n};\n\nvoid Foo::pub() {\n  this->\n}\n\nvoid test() {\n  Foo f;\n  f.\n}"}}}
-
-Content-Length: 151
-
-{"jsonrpc":"2.0","id":2,"method":"textDocument/completion","params":{"textDocument":{"uri":"file:///main.cpp"},"position":{"line":12,"character":8}}}
-#      CHECK:  "id": 2,
-# CHECK-NEXT:  "jsonrpc": "2.0",
-# CHECK-NEXT:  "result": {
-# CHECK-NEXT:    "isIncomplete": false,
-# CHECK-NEXT:    "items": [
-# CHECK-NEXT:      {
-# CHECK-NEXT:        "detail": "void",
-# CHECK-NEXT:        "filterText": "priv",
-# CHECK-NEXT:        "insertText": "priv",
-# CHECK-NEXT:        "insertTextFormat": 1,
-# CHECK-NEXT:        "kind": 2,
-# CHECK-NEXT:        "label": "priv()",
-# CHECK-NEXT:        "sortText": "{{.*}}priv"
-# CHECK-NEXT:      },
-# CHECK-NEXT:      {
-# CHECK-NEXT:        "detail": "void",
-# CHECK-NEXT:        "filterText": "prot",
-# CHECK-NEXT:        "insertText": "prot",
-# CHECK-NEXT:        "insertTextFormat": 1,
-# CHECK-NEXT:        "kind": 2,
-# CHECK-NEXT:        "label": "prot()",
-# CHECK-NEXT:        "sortText": "{{.*}}prot"
-# CHECK-NEXT:      },
-# CHECK-NEXT:      {
-# CHECK-NEXT:        "detail": "void",
-# CHECK-NEXT:        "filterText": "pub",
-# CHECK-NEXT:        "insertText": "pub",
-# CHECK-NEXT:        "insertTextFormat": 1,
-# CHECK-NEXT:        "kind": 2,
-# CHECK-NEXT:        "label": "pub()",
-# CHECK-NEXT:        "sortText": "{{.*}}pub"
-# CHECK-NEXT:      },
-Content-Length: 151
-
-{"jsonrpc":"2.0","id":3,"method":"textDocument/completion","params":{"textDocument":{"uri":"file:///main.cpp"},"position":{"line":17,"character":4}}}
-#      CHECK:  "id": 3,
-# CHECK-NEXT:  "jsonrpc": "2.0",
-# CHECK-NEXT:  "result": {
-# CHECK-NEXT:    "isIncomplete": false,
-# CHECK-NEXT:    "items": [
-# CHECK-NEXT:      {
-# CHECK-NEXT:        "detail": "void",
-# CHECK-NEXT:        "filterText": "pub",
-# CHECK-NEXT:        "insertText": "pub",
-# CHECK-NEXT:        "insertTextFormat": 1,
-# CHECK-NEXT:        "kind": 2,
-# CHECK-NEXT:        "label": "pub()",
-# CHECK-NEXT:        "sortText": "{{.*}}pub"
-# CHECK-NEXT:      }
-#  CHECK-NOT:        "label": "priv()",
-#  CHECK-NOT:        "label": "prot()",
-#      CHECK:    ]
-Content-Length: 58
-
-{"jsonrpc":"2.0","id":4,"method":"shutdown","params":null}
-Content-Length: 33
-
-{"jsonrpc":"2.0":"method":"exit"}

test/clangd/completion-qualifiers.test

-# RUN: clangd -pretty -run-synchronously < %s | FileCheck -strict-whitespace %s
-Content-Length: 125
-
-{"jsonrpc":"2.0","id":0,"method":"initialize","params":{"processId":123,"rootPath":"clangd","capabilities":{},"trace":"off"}}
-Content-Length: 297
-
-{"jsonrpc":"2.0","method":"textDocument/didOpen","params":{"textDocument":{"uri":"file:///main.cpp","languageId":"cpp","version":1,"text":"class Foo {\n  public:\n    int foo() const;\n    int bar() const;\n};\n\nclass Bar : public Foo {\n  int foo() const;\n};\n\nvoid test() {\n  Bar().\n}"}}}
-Content-Length: 151
-
-{"jsonrpc":"2.0","id":2,"method":"textDocument/completion","params":{"textDocument":{"uri":"file:///main.cpp"},"position":{"line":11,"character":8}}}
-#      CHECK:  "id": 2,
-# CHECK-NEXT:  "jsonrpc": "2.0",
-# CHECK-NEXT:  "result": {
-# CHECK-NEXT:    "isIncomplete": false,
-# CHECK-NEXT:    "items": [
-# Eligible functions are at the top of the list.
-# CHECK-NEXT:      {
-# CHECK-NEXT:        "detail": "int",
-# CHECK-NEXT:        "filterText": "bar",
-# CHECK-NEXT:        "insertText": "bar",
-# CHECK-NEXT:        "insertTextFormat": 1,
-# CHECK-NEXT:        "kind": 2,
-# CHECK-NEXT:        "label": "bar() const",
-# CHECK-NEXT:        "sortText": "{{.*}}bar"
-# CHECK-NEXT:      },
-# CHECK-NEXT:      {
-# CHECK-NEXT:        "detail": "int",
-# CHECK-NEXT:        "filterText": "foo",
-# CHECK-NEXT:        "insertText": "foo",
-# CHECK-NEXT:        "insertTextFormat": 1,
-# CHECK-NEXT:        "kind": 2,
-# CHECK-NEXT:        "label": "Foo::foo() const",
-# CHECK-NEXT:        "sortText": "{{.*}}foo"
-# CHECK-NEXT:      },
-# Ineligible private functions are not present.
-#  CHECK-NOT:        "label": "foo() const",
-#      CHECK:    ]
-Content-Length: 44
-
-{"jsonrpc":"2.0","id":4,"method":"shutdown"}
-Content-Length: 33
-
-{"jsonrpc":"2.0":"method":"exit"}

test/clangd/completion-snippet.test

-# RUN: clangd -pretty -run-synchronously -enable-snippets < %s | FileCheck -strict-whitespace %s
-# It is absolutely vital that this file has CRLF line endings.
-#
-Content-Length: 125
-
-{"jsonrpc":"2.0","id":0,"method":"initialize","params":{"processId":123,"rootPath":"clangd","capabilities":{},"trace":"off"}}
-
-Content-Length: 246
-
-{"jsonrpc":"2.0","method":"textDocument/didOpen","params":{"textDocument":{"uri":"file:///main.cpp","languageId":"cpp","version":1,"text":"struct fake { int a, bb, ccc; int f(int i, const float f) const; };\nint main() {\n  fake f;\n  f.\n}\n"}}}
-
-Content-Length: 148
-
-{"jsonrpc":"2.0","id":1,"method":"textDocument/completion","params":{"textDocument":{"uri":"file:///main.cpp"},"position":{"line":3,"character":5}}}
-#      CHECK:  "id": 1,
-# CHECK-NEXT:  "jsonrpc": "2.0",
-# CHECK-NEXT:  "result": {
-# CHECK-NEXT:    "isIncomplete": false,
-# CHECK-NEXT:    "items": [
-# CHECK-NEXT:      {
-# CHECK-NEXT:        "detail": "int",
-# CHECK-NEXT:        "filterText": "a",
-# CHECK-NEXT:        "insertText": "a",
-# CHECK-NEXT:        "insertTextFormat": 1,
-# CHECK-NEXT:        "kind": 5,
-# CHECK-NEXT:        "label": "a",
-# CHECK-NEXT:        "sortText": "{{.*}}a"
-# CHECK-NEXT:      },
-# CHECK-NEXT:      {
-# CHECK-NEXT:        "detail": "int",
-# CHECK-NEXT:        "filterText": "bb",
-# CHECK-NEXT:        "insertText": "bb",
-# CHECK-NEXT:        "insertTextFormat": 1,
-# CHECK-NEXT:        "kind": 5,
-# CHECK-NEXT:        "label": "bb",
-# CHECK-NEXT:        "sortText": "{{.*}}bb"
-# CHECK-NEXT:      },
-# CHECK-NEXT:      {
-# CHECK-NEXT:        "detail": "int",
-# CHECK-NEXT:        "filterText": "ccc",
-# CHECK-NEXT:        "insertText": "ccc",
-# CHECK-NEXT:        "insertTextFormat": 1,
-# CHECK-NEXT:        "kind": 5,
-# CHECK-NEXT:        "label": "ccc",
-# CHECK-NEXT:        "sortText": "{{.*}}ccc"
-# CHECK-NEXT:      },
-# CHECK-NEXT:      {
-# CHECK-NEXT:        "detail": "int",
-# CHECK-NEXT:        "filterText": "f",
-# CHECK-NEXT:        "insertText": "f(${1:int i}, ${2:const float f})",
-# CHECK-NEXT:        "insertTextFormat": 2,
-# CHECK-NEXT:        "kind": 2,
-# CHECK-NEXT:        "label": "f(int i, const float f) const",
-# CHECK-NEXT:        "sortText": "{{.*}}f"
-# CHECK-NEXT:      },
-# CHECK-NEXT:      {
-# CHECK-NEXT:        "filterText": "fake",
-# CHECK-NEXT:        "insertText": "fake::",
-# CHECK-NEXT:        "insertTextFormat": 1,
-# CHECK-NEXT:        "kind": 7,
-# CHECK-NEXT:        "label": "fake::",
-# CHECK-NEXT:        "sortText": "{{.*}}fake"
-# CHECK-NEXT:      },
-#      CHECK:      {
-#      CHECK:        "detail": "void",
-# CHECK-NEXT:        "filterText": "~fake",
-# CHECK-NEXT:        "insertText": "~fake()",
-# CHECK-NEXT:        "insertTextFormat": 1,
-# CHECK-NEXT:        "kind": 4,
-# CHECK-NEXT:        "label": "~fake()",
-# CHECK-NEXT:        "sortText": "{{.*}}~fake"
-# CHECK-NEXT:      }
-# CHECK-NEXT:    ]
-# CHECK-NEXT:  }
-# Update the source file and check for completions again.
-Content-Length: 226
-
-{"jsonrpc":"2.0","method":"textDocument/didChange","params":{"textDocument":{"uri":"file:///main.cpp","version":2},"contentChanges":[{"text":"struct fancy { int (*func())(int, int); };\nint main() {\n  fancy f;\n  f.\n}\n"}]}}
-
-Content-Length: 148
-
-{"jsonrpc":"2.0","id":3,"method":"textDocument/completion","params":{"textDocument":{"uri":"file:///main.cpp"},"position":{"line":3,"character":5}}}
-#      CHECK:  "id": 3,
-# CHECK-NEXT:  "jsonrpc": "2.0",
-# CHECK-NEXT:  "result": {
-# CHECK-NEXT:    "isIncomplete": false,
-# CHECK-NEXT:    "items": [
-# CHECK-NEXT:      {
-# CHECK-NEXT:        "detail": "int (*)(int, int)",
-# CHECK-NEXT:        "filterText": "func",
-# CHECK-NEXT:        "insertText": "func()",
-# CHECK-NEXT:        "insertTextFormat": 1,
-# CHECK-NEXT:        "kind": 2,
-# CHECK-NEXT:        "label": "func()",
-# CHECK-NEXT:        "sortText": "{{.*}}func"
-# CHECK-NEXT:      },
-Content-Length: 44
-
-{"jsonrpc":"2.0","id":4,"method":"shutdown"}
-Content-Length: 33
-
-{"jsonrpc":"2.0":"method":"exit"}

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 "ClangdServer.h"
 #include "Compiler.h"
+#include "Matchers.h"
 #include "Protocol.h"
 #include "TestFS.h"
 #include "gmock/gmock.h"
 #include "gtest/gtest.h"
 
 namespace clang {
 namespace clangd {
 // Let GMock print completion items.
 void PrintTo(const CompletionItem &I, std::ostream *O) {
   llvm::raw_os_ostream OS(*O);
-  OS << toJSON(I);
+  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 << "}";
 }
 
 namespace {
 using namespace llvm;
 using ::testing::AllOf;
 using ::testing::Contains;
 using ::testing::ElementsAre;
-using ::testing::Matcher;
 using ::testing::Not;
 
 class IgnoreDiagnostics : public DiagnosticsConsumer {
   void onDiagnosticsReady(
       PathRef File, Tagged<std::vector<DiagWithFixIts>> Diagnostics) override {}
 };
 
 struct StringWithPos {
assert(StringRef(WithoutMarker).find('^') == StringRef::npos &&
          "There were multiple occurences of ^ inside Text");
 
   auto MarkerPos = offsetToPosition(WithoutMarker, MarkerOffset);
   return {std::move(WithoutMarker), MarkerPos};
 }
 
 // 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(PlainText, Text, "") {
+  return arg.insertTextFormat == clangd::InsertTextFormat::PlainText &&
+         arg.insertText == Text;
+}
+MATCHER_P(Snippet, Text, "") {
+  return arg.insertTextFormat == clangd::InsertTextFormat::Snippet &&
+         arg.insertText == Text;
+}
 // Shorthand for Contains(Named(Name)).
 Matcher<const std::vector<CompletionItem> &> Has(std::string Name) {
   return Contains(Named(std::move(Name)));
 }
-MATCHER(IsDocumented, "") { return !arg.documentation.empty(); }
-MATCHER(IsSnippet, "") {
-  return arg.kind == clangd::CompletionItemKind::Snippet;
+Matcher<const std::vector<CompletionItem> &> Has(std::string Name,
+                                                 CompletionItemKind K) {
+  return Contains(AllOf(Named(std::move(Name)), Kind(K)));
 }
-// This is hard to write as a function, because matchers may be polymorphic.
-#define EXPECT_IFF(condition, value, matcher)                                  \
-  do {                                                                         \
-    if (condition)                                                             \
-      EXPECT_THAT(value, matcher);                                             \
-    else                                                                       \
-      EXPECT_THAT(value, ::testing::Not(matcher));                             \
-  } while (0)
+MATCHER(IsDocumented, "") { return !arg.documentation.empty(); }
 
 CompletionList completions(StringRef Text,
                            clangd::CodeCompleteOptions Opts = {}) {
   MockFSProvider FS;
   MockCompilationDatabase CDB;
   IgnoreDiagnostics DiagConsumer;
   ClangdServer Server(CDB, DiagConsumer, FS, getDefaultAsyncThreadsCount(),
                       /*StorePreamblesInMemory=*/true,
EXPECT_THAT(Results, AllOf(Has(Opts.EnableSnippets ? "method()" : "method"),
                              Has("field")));
   EXPECT_IFF(Opts.IncludeIneligibleResults, Results, Has("private_field"));
   // Global items.
   EXPECT_THAT(Results, Not(AnyOf(Has("global_var"), Has("global_func"),
                                  Has("global_func()"), Has("GlobalClass"),
                                  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, Not(Contains(IsSnippet())));
+  EXPECT_THAT(Results, Not(Contains(Kind(CompletionItemKind::Snippet))));
   // Check documentation.
   EXPECT_IFF(Opts.IncludeBriefComments, Results, Contains(IsDocumented()));
 }
 
 void TestGlobalScopeCompletion(clangd::CodeCompleteOptions Opts) {
   auto Results = completions(R"cpp(
 #define MACRO X
 
)cpp",
   EXPECT_IFF(Opts.IncludeGlobals, Results,
              AllOf(Has("global_var"),
                    Has(Opts.EnableSnippets ? "global_func()" : "global_func"),
                    Has("GlobalClass")));
   // A macro.
   EXPECT_IFF(Opts.IncludeMacros, Results, Has("MACRO"));
   // Local items. Must be present always.
   EXPECT_THAT(Results, AllOf(Has("local_var"), Has("LocalClass"),
-                             Contains(IsSnippet())));
+                             Contains(Kind(CompletionItemKind::Snippet))));
   // Check documentation.
   EXPECT_IFF(Opts.IncludeBriefComments, Results, Contains(IsDocumented()));
 }
 
 TEST(CompletionTest, CompletionOptions) {
   clangd::CodeCompleteOptions Opts;
   for (bool IncludeMacros : {true, false}) {
     Opts.IncludeMacros = IncludeMacros;
auto Results =
       Server
           .codeComplete(File, Example.MarkerPos, clangd::CodeCompleteOptions(),
                         StringRef(Example.Text))
           .get()
           .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",
+                             Opts);
+  EXPECT_THAT(Results.items,
+              HasSubsequence(PlainText("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");
+  EXPECT_THAT(Results.items, Has("function", CompletionItemKind::Function));
+  EXPECT_THAT(Results.items, Has("variable", CompletionItemKind::Variable));
+  EXPECT_THAT(Results.items, Has("int", CompletionItemKind::Keyword));
+  EXPECT_THAT(Results.items, Has("Struct", CompletionItemKind::Class));
+  EXPECT_THAT(Results.items, Has("MACRO", CompletionItemKind::Text));
+
+  clangd::CodeCompleteOptions Opts;
+  Opts.EnableSnippets = true; // Needed for code patterns.
+
+  Results = completions("nam^");
+  EXPECT_THAT(Results.items, Has("namespace", CompletionItemKind::Snippet));
+}
+
 } // namespace
 } // namespace clangd
 } // namespace clang

unittests/clangd/Matchers.h

+//===-- Matchers.h ----------------------------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// GMock matchers that aren't specific to particular tests.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_TOOLS_EXTRA_UNITTESTS_CLANGD_MATCHERS_H
+#define LLVM_CLANG_TOOLS_EXTRA_UNITTESTS_CLANGD_MATCHERS_H
+#include "gmock/gmock.h"
+
+namespace clang {
+namespace clangd {
+using ::testing::Matcher;
+
+// EXPECT_IFF expects matcher if condition is true, and Not(matcher) if false.
+// This is hard to write as a function, because matchers may be polymorphic.
+#define EXPECT_IFF(condition, value, matcher)                                  \
+  do {                                                                         \
+    if (condition)                                                             \
+      EXPECT_THAT(value, matcher);                                             \
+    else                                                                       \
+      EXPECT_THAT(value, ::testing::Not(matcher));                             \
+  } while (0)
+
+// HasSubsequence(m1, m2, ...) matches a vector containing elements that match
+// m1, m2 ... in that order.
+template <typename T>
+class SubsequenceMatcher
+    : public ::testing::MatcherInterface<const std::vector<T> &> {
+  std::vector<Matcher<T>> Matchers;
+
+public:
+  SubsequenceMatcher(std::vector<Matcher<T>> M) : Matchers(M) {}
+
+  void DescribeTo(std::ostream *OS) const {
+    *OS << "Contains the subsequence [";
+    const char *Sep = "";
+    for (const auto &M : Matchers) {
+      *OS << Sep;
+      M.DescribeTo(OS);
+      Sep = ", ";
+    }
+    *OS << "]";
+  }
+
+  bool MatchAndExplain(const std::vector<T> &V,
+                       ::testing::MatchResultListener *L) const {
+    std::vector<int> Matches(Matchers.size());
+    size_t I = 0;
+    for (size_t J = 0; I < Matchers.size() && J < V.size(); ++J)
+      if (Matchers[I].Matches(V[J]))
+        Matches[I++] = J;
+    if (I == Matchers.size()) // We exhausted all matchers.
+      return true;
+    if (L->IsInterested()) {
+      *L << "\n  Matched:";
+      for (size_t K = 0; K < I; ++K) {
+        *L << "\n\t";
+        Matchers[K].DescribeTo(L->stream());
+        *L << " ==> " << ::testing::PrintToString(V[Matches[K]]);
+      }
+      *L << "\n\t";
+      Matchers[I].DescribeTo(L->stream());
+      *L << " ==> no subsequent match";
+    }
+    return false;
+  }
+};
+
+template <typename... M> class PolySubsequenceMatcher {
+  std::tuple<M...> Matchers;
+
+public:
+  PolySubsequenceMatcher(M &&... Args)
+      : Matchers(std::make_tuple(std::forward<M>(Args)...)) {}
+
+  template <typename T> operator Matcher<const std::vector<T> &>() const {
+    return ::testing::MakeMatcher(new SubsequenceMatcher<T>(
+        TypedMatchers<T>(llvm::index_sequence_for<M...>{})));
+  }
+
+private:
+  template <typename T, size_t... I>
+  std::vector<Matcher<T>> TypedMatchers(llvm::index_sequence<I...>) const {
+    return {std::get<I>(Matchers)...};
+  }
+};
+
+template <typename... Args>
+PolySubsequenceMatcher<Args...> HasSubsequence(Args &&... M) {
+  return PolySubsequenceMatcher<Args...>(std::forward<Args>(M)...);
+}
+
+} // namespace clangd
+} // namespace clang
+#endif