[Syntax] Add Trivia C++ unit tests

include/swift/Syntax/Trivia.h

@@ -120,9 +120,6 @@ enum class TriviaKind {
 
   /// A backtick '`' character, used to escape identifiers.
   Backtick,
-
-  /// A semicolon ';' character, used for delimiting statements.
-  Semicolon
 };
 
 /// A contiguous stretch of a single kind of trivia. The constiuent part of
@@ -187,11 +184,6 @@ struct TriviaPiece {
     return TriviaPiece {TriviaKind::Backtick, 1, OwnedString{}};
   }
 
-  /// Return a piece of trivia for some number of semicolons in a row.
-  static TriviaPiece semicolon(unsigned Count) {
-    return TriviaPiece {TriviaKind::Semicolon, Count, OwnedString{}};
-  }
-
   void accumulateAbsolutePosition(AbsolutePosition &Pos) const;
 
   /// Print a debug representation of this trivia piece to the provided output
@@ -200,6 +192,16 @@ struct TriviaPiece {
 
   /// Print this piece of trivia to the provided output stream.
   void print(llvm::raw_ostream &OS) const;
+
+  bool operator==(const TriviaPiece &Other) const {
+    return Kind == Other.Kind &&
+           Count == Other.Count &&
+           Text.str().compare(Other.Text.str()) == 0;
+  }
+
+  bool operator!=(const TriviaPiece &Other) const {
+    return !(*this == Other);
+  }
 };
 
 using TriviaList = std::deque<TriviaPiece>;
@@ -233,20 +235,23 @@ struct Trivia {
   ///
   /// Precondition: !empty()
   const TriviaPiece &front() const {
+    assert(!empty());
     return Pieces.front();
   }
 
   /// Return a reference to the last piece.
   ///
   /// Precondition: !empty()
   const TriviaPiece &back() const  {
+    assert(!empty());
     return Pieces.back();
   }
 
   /// Remove the last piece from the Trivia collection.
   ///
   /// Precondition: !empty()
   void pop_back() {
+    assert(!empty());
     Pieces.pop_back();
   }
 
@@ -283,41 +288,74 @@ struct Trivia {
     return find(Kind) != end();
   }
 
+  bool operator==(const Trivia &Other) const {
+    if (Pieces.size() != Other.size()) {
+      return false;
+    }
+
+    for (size_t i = 0; i < Pieces.size(); ++i) {
+      if (Pieces[i] != Other.Pieces[i]) {
+        return false;
+      }
+    }
+
+    return true;
+  }
+
+  bool operator!=(const Trivia &Other) const {
+    return !(*this == Other);
+  }
+
   /// Return a collection of trivia of some number of space characters in a row.
   static Trivia spaces(unsigned Count) {
+    if (Count == 0) {
+      return {};
+    }
     return {{ TriviaPiece {TriviaKind::Space, Count, OwnedString{}} }};
   }
 
   /// Return a collection of trivia of some number of tab characters in a row.
   static Trivia tabs(unsigned Count) {
+    if (Count == 0) {
+      return {};
+    }
     return {{ TriviaPiece {TriviaKind::Tab, Count, OwnedString{}} }};
   }
 
   /// Return a collection of trivia of some number of newline characters
   // in a row.
   static Trivia newlines(unsigned Count) {
+    if (Count == 0) {
+      return {};
+    }
     return {{ TriviaPiece {TriviaKind::Newline, Count, OwnedString{}} }};
   }
 
   /// Return a collection of trivia with a single line of ('//')
   // developer comment.
   static Trivia lineComment(const OwnedString Text) {
+    assert(Text.str().startswith("//"));
     return {{ TriviaPiece {TriviaKind::LineComment, 1, Text} }};
   }
 
   /// Return a collection of trivia with a block comment ('/* ... */')
   static Trivia blockComment(const OwnedString Text) {
+    assert(Text.str().startswith("/*"));
+    assert(Text.str().endswith("*/"));
     return {{ TriviaPiece {TriviaKind::BlockComment, 1, Text} }};
   }
 
   /// Return a collection of trivia with a single line of ('///') doc comment.
   static Trivia docLineComment(const OwnedString Text) {
+    assert(Text.str().startswith("///"));
     return {{ TriviaPiece {TriviaKind::DocLineComment, 1, Text} }};
   }
 
   /// Return a collection of trivia with a documentation block
   // comment ('/** ... */')
   static Trivia docBlockComment(const OwnedString Text) {
+    assert(Text.str().startswith("/**"));
+    assert(Text.str().endswith("*/"));
     return {{ TriviaPiece {TriviaKind::DocBlockComment, 1, Text} }};
   }
 
@@ -326,11 +364,6 @@ struct Trivia {
   static Trivia backtick() {
     return {{ TriviaPiece {TriviaKind::Backtick, 1, OwnedString{}} }};
   }
-
-  /// Return a piece of trivia for some number of semicolons in a row.
-  static Trivia semicolon() {
-    return {{ TriviaPiece {TriviaKind::Semicolon, 1, OwnedString{}} }};
-  }
 };
 }
 }

lib/Syntax/Trivia.cpp

@@ -80,9 +80,6 @@ void TriviaPiece::dump(llvm::raw_ostream &OS, unsigned Indent) const {
   case TriviaKind::Backtick:
     OS << "backtick " << Count;
     break;
-  case TriviaKind::Semicolon:
-    OS << "semicolon " << Count;
-    break;
   }
   OS << ')';
 }
@@ -100,7 +97,6 @@ void TriviaPiece::accumulateAbsolutePosition(AbsolutePosition &Pos) const {
     break;
   case TriviaKind::Space:
   case TriviaKind::Backtick:
-  case TriviaKind::Semicolon:
   case TriviaKind::Tab:
   case TriviaKind::VerticalTab:
   case TriviaKind::Formfeed:
@@ -135,8 +131,6 @@ void TriviaPiece::print(llvm::raw_ostream &OS) const {
   case TriviaKind::Backtick:
     printRepeated(OS, '`', Count);
     break;
-  case TriviaKind::Semicolon:
-    printRepeated(OS, ';', Count);
   }
 }
 

unittests/Syntax/CMakeLists.txt

@@ -5,6 +5,7 @@ add_swift_unittest(SwiftSyntaxTests
   RawSyntaxTests.cpp
   StmtSyntaxTests.cpp
   ThreadSafeCachingTests.cpp
+  TriviaTests.cpp
   TypeSyntaxTests.cpp)
 
 target_link_libraries(SwiftSyntaxTests