Import LLVM 10.0.0 release including clang, lld and lldb.

ok hackroom
tested by plenty

1 files changed, 1721 insertions, 0 deletions

diff --git a/gnu/llvm/clang/unittests/Tooling/RefactoringTest.cpp b/gnu/llvm/clang/unittests/Tooling/RefactoringTest.cpp
new file mode 100644
index 00000000000..5949c53d8ea
--- /dev/null
+++ b/gnu/llvm/clang/unittests/Tooling/RefactoringTest.cpp
@@ -0,0 +1,1721 @@
+//===- unittest/Tooling/RefactoringTest.cpp - Refactoring unit tests ------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Tooling/Refactoring.h"
+#include "ReplacementTest.h"
+#include "RewriterTestContext.h"
+#include "clang/AST/ASTConsumer.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/AST/DeclCXX.h"
+#include "clang/AST/DeclGroup.h"
+#include "clang/AST/RecursiveASTVisitor.h"
+#include "clang/Basic/Diagnostic.h"
+#include "clang/Basic/DiagnosticOptions.h"
+#include "clang/Basic/FileManager.h"
+#include "clang/Basic/LangOptions.h"
+#include "clang/Basic/SourceManager.h"
+#include "clang/Format/Format.h"
+#include "clang/Frontend/CompilerInstance.h"
+#include "clang/Frontend/FrontendAction.h"
+#include "clang/Frontend/TextDiagnosticPrinter.h"
+#include "clang/Rewrite/Core/Rewriter.h"
+#include "clang/Tooling/Refactoring/AtomicChange.h"
+#include "clang/Tooling/Tooling.h"
+#include "llvm/ADT/SmallString.h"
+#include "llvm/Support/VirtualFileSystem.h"
+#include "gtest/gtest.h"
+
+namespace clang {
+namespace tooling {
+
+TEST_F(ReplacementTest, CanDeleteAllText) {
+  FileID ID = Context.createInMemoryFile("input.cpp", "text");
+  SourceLocation Location = Context.getLocation(ID, 1, 1);
+  Replacement Replace(createReplacement(Location, 4, ""));
+  EXPECT_TRUE(Replace.apply(Context.Rewrite));
+  EXPECT_EQ("", Context.getRewrittenText(ID));
+}
+
+TEST_F(ReplacementTest, CanDeleteAllTextInTextWithNewlines) {
+  FileID ID = Context.createInMemoryFile("input.cpp", "line1\nline2\nline3");
+  SourceLocation Location = Context.getLocation(ID, 1, 1);
+  Replacement Replace(createReplacement(Location, 17, ""));
+  EXPECT_TRUE(Replace.apply(Context.Rewrite));
+  EXPECT_EQ("", Context.getRewrittenText(ID));
+}
+
+TEST_F(ReplacementTest, CanAddText) {
+  FileID ID = Context.createInMemoryFile("input.cpp", "");
+  SourceLocation Location = Context.getLocation(ID, 1, 1);
+  Replacement Replace(createReplacement(Location, 0, "result"));
+  EXPECT_TRUE(Replace.apply(Context.Rewrite));
+  EXPECT_EQ("result", Context.getRewrittenText(ID));
+}
+
+TEST_F(ReplacementTest, CanReplaceTextAtPosition) {
+  FileID ID = Context.createInMemoryFile("input.cpp",
+                                         "line1\nline2\nline3\nline4");
+  SourceLocation Location = Context.getLocation(ID, 2, 3);
+  Replacement Replace(createReplacement(Location, 12, "x"));
+  EXPECT_TRUE(Replace.apply(Context.Rewrite));
+  EXPECT_EQ("line1\nlixne4", Context.getRewrittenText(ID));
+}
+
+TEST_F(ReplacementTest, CanReplaceTextAtPositionMultipleTimes) {
+  FileID ID = Context.createInMemoryFile("input.cpp",
+                                         "line1\nline2\nline3\nline4");
+  SourceLocation Location1 = Context.getLocation(ID, 2, 3);
+  Replacement Replace1(createReplacement(Location1, 12, "x\ny\n"));
+  EXPECT_TRUE(Replace1.apply(Context.Rewrite));
+  EXPECT_EQ("line1\nlix\ny\nne4", Context.getRewrittenText(ID));
+
+  // Since the original source has not been modified, the (4, 4) points to the
+  // 'e' in the original content.
+  SourceLocation Location2 = Context.getLocation(ID, 4, 4);
+  Replacement Replace2(createReplacement(Location2, 1, "f"));
+  EXPECT_TRUE(Replace2.apply(Context.Rewrite));
+  EXPECT_EQ("line1\nlix\ny\nnf4", Context.getRewrittenText(ID));
+}
+
+TEST_F(ReplacementTest, ApplyFailsForNonExistentLocation) {
+  Replacement Replace("nonexistent-file.cpp", 0, 1, "");
+  EXPECT_FALSE(Replace.apply(Context.Rewrite));
+}
+
+TEST_F(ReplacementTest, CanRetrivePath) {
+  Replacement Replace("/path/to/file.cpp", 0, 1, "");
+  EXPECT_EQ("/path/to/file.cpp", Replace.getFilePath());
+}
+
+TEST_F(ReplacementTest, ReturnsInvalidPath) {
+  Replacement Replace1(Context.Sources, SourceLocation(), 0, "");
+  EXPECT_TRUE(Replace1.getFilePath().empty());
+
+  Replacement Replace2;
+  EXPECT_TRUE(Replace2.getFilePath().empty());
+}
+
+// Checks that an llvm::Error instance contains a ReplacementError with expected
+// error code, expected new replacement, and expected existing replacement.
+static bool checkReplacementError(llvm::Error &&Error,
+                                  replacement_error ExpectedErr,
+                                  llvm::Optional<Replacement> ExpectedExisting,
+                                  llvm::Optional<Replacement> ExpectedNew) {
+  if (!Error) {
+    llvm::errs() << "Error is a success.";
+    return false;
+  }
+  std::string ErrorMessage;
+  llvm::raw_string_ostream OS(ErrorMessage);
+  llvm::handleAllErrors(std::move(Error), [&](const ReplacementError &RE) {
+    llvm::errs() << "Handling error...\n";
+    if (ExpectedErr != RE.get())
+      OS << "Unexpected error code: " << int(RE.get()) << "\n";
+    if (ExpectedExisting != RE.getExistingReplacement()) {
+      OS << "Expected Existing != Actual Existing.\n";
+      if (ExpectedExisting.hasValue())
+        OS << "Expected existing replacement: " << ExpectedExisting->toString()
+           << "\n";
+      if (RE.getExistingReplacement().hasValue())
+        OS << "Actual existing replacement: "
+           << RE.getExistingReplacement()->toString() << "\n";
+    }
+    if (ExpectedNew != RE.getNewReplacement()) {
+      OS << "Expected New != Actual New.\n";
+      if (ExpectedNew.hasValue())
+        OS << "Expected new replacement: " << ExpectedNew->toString() << "\n";
+      if (RE.getNewReplacement().hasValue())
+        OS << "Actual new replacement: " << RE.getNewReplacement()->toString()
+           << "\n";
+    }
+  });
+  OS.flush();
+  if (ErrorMessage.empty()) return true;
+  llvm::errs() << ErrorMessage;
+  return false;
+}
+
+TEST_F(ReplacementTest, FailAddReplacements) {
+  Replacements Replaces;
+  Replacement Deletion("x.cc", 0, 10, "3");
+  auto Err = Replaces.add(Deletion);
+  EXPECT_TRUE(!Err);
+  llvm::consumeError(std::move(Err));
+
+  Replacement OverlappingReplacement("x.cc", 0, 2, "a");
+  Err = Replaces.add(OverlappingReplacement);
+  EXPECT_TRUE(checkReplacementError(std::move(Err),
+                                    replacement_error::overlap_conflict,
+                                    Deletion, OverlappingReplacement));
+
+  Replacement ContainedReplacement("x.cc", 2, 2, "a");
+  Err = Replaces.add(Replacement(ContainedReplacement));
+  EXPECT_TRUE(checkReplacementError(std::move(Err),
+                                    replacement_error::overlap_conflict,
+                                    Deletion, ContainedReplacement));
+
+  Replacement WrongPathReplacement("y.cc", 20, 2, "");
+  Err = Replaces.add(WrongPathReplacement);
+  EXPECT_TRUE(checkReplacementError(std::move(Err),
+                                    replacement_error::wrong_file_path,
+                                    Deletion, WrongPathReplacement));
+
+  EXPECT_EQ(1u, Replaces.size());
+  EXPECT_EQ(Deletion, *Replaces.begin());
+}
+
+TEST_F(ReplacementTest, DeletionInReplacements) {
+  Replacements Replaces;
+  Replacement R("x.cc", 0, 10, "3");
+  auto Err = Replaces.add(R);
+  EXPECT_TRUE(!Err);
+  llvm::consumeError(std::move(Err));
+  Err = Replaces.add(Replacement("x.cc", 0, 2, ""));
+  EXPECT_TRUE(!Err);
+  llvm::consumeError(std::move(Err));
+  Err = Replaces.add(Replacement("x.cc", 2, 2, ""));
+  EXPECT_TRUE(!Err);
+  llvm::consumeError(std::move(Err));
+  EXPECT_EQ(1u, Replaces.size());
+  EXPECT_EQ(R, *Replaces.begin());
+}
+
+TEST_F(ReplacementTest, OverlappingReplacements) {
+  Replacements Replaces;
+  auto Err = Replaces.add(Replacement("x.cc", 0, 3, "345"));
+  EXPECT_TRUE(!Err);
+  llvm::consumeError(std::move(Err));
+  Err = Replaces.add(Replacement("x.cc", 2, 3, "543"));
+  EXPECT_TRUE(!Err);
+  llvm::consumeError(std::move(Err));
+
+  EXPECT_EQ(1u, Replaces.size());
+  EXPECT_EQ(Replacement("x.cc", 0, 5, "34543"), *Replaces.begin());
+
+  Err = Replaces.add(Replacement("x.cc", 2, 1, "5"));
+  EXPECT_TRUE(!Err);
+  llvm::consumeError(std::move(Err));
+  EXPECT_EQ(1u, Replaces.size());
+  EXPECT_EQ(Replacement("x.cc", 0, 5, "34543"), *Replaces.begin());
+}
+
+TEST_F(ReplacementTest, AddAdjacentInsertionAndReplacement) {
+  Replacements Replaces;
+  // Test adding an insertion at the offset of an existing replacement.
+  auto Err = Replaces.add(Replacement("x.cc", 10, 3, "replace"));
+  EXPECT_TRUE(!Err);
+  llvm::consumeError(std::move(Err));
+  Err = Replaces.add(Replacement("x.cc", 10, 0, "insert"));
+  EXPECT_TRUE(!Err);
+  llvm::consumeError(std::move(Err));
+  EXPECT_EQ(Replaces.size(), 2u);
+
+  Replaces.clear();
+  // Test overlap with an existing insertion.
+  Err = Replaces.add(Replacement("x.cc", 10, 0, "insert"));
+  EXPECT_TRUE(!Err);
+  llvm::consumeError(std::move(Err));
+  Err = Replaces.add(Replacement("x.cc", 10, 3, "replace"));
+  EXPECT_TRUE(!Err);
+  llvm::consumeError(std::move(Err));
+  EXPECT_EQ(Replaces.size(), 2u);
+}
+
+TEST_F(ReplacementTest, MergeNewDeletions) {
+  Replacements Replaces;
+  Replacement ContainingReplacement("x.cc", 0, 10, "");
+  auto Err = Replaces.add(ContainingReplacement);
+  EXPECT_TRUE(!Err);
+  llvm::consumeError(std::move(Err));
+
+  Err = Replaces.add(Replacement("x.cc", 5, 3, ""));
+  EXPECT_TRUE(!Err);
+  llvm::consumeError(std::move(Err));
+
+  Err = Replaces.add(Replacement("x.cc", 0, 10, ""));
+  EXPECT_TRUE(!Err);
+  llvm::consumeError(std::move(Err));
+
+  Err = Replaces.add(Replacement("x.cc", 5, 5, ""));
+  EXPECT_TRUE(!Err);
+  llvm::consumeError(std::move(Err));
+
+  EXPECT_EQ(1u, Replaces.size());
+  EXPECT_EQ(*Replaces.begin(), ContainingReplacement);
+}
+
+TEST_F(ReplacementTest, MergeOverlappingButNotAdjacentReplacement) {
+  Replacements Replaces;
+  auto Err = Replaces.add(Replacement("x.cc", 0, 2, ""));
+  EXPECT_TRUE(!Err);
+  llvm::consumeError(std::move(Err));
+
+  Err = Replaces.add(Replacement("x.cc", 5, 5, ""));
+  EXPECT_TRUE(!Err);
+  llvm::consumeError(std::move(Err));
+
+  Replacement After = Replacement("x.cc", 10, 5, "");
+  Err = Replaces.add(After);
+  EXPECT_TRUE(!Err);
+  llvm::consumeError(std::move(Err));
+
+  Replacement ContainingReplacement("x.cc", 0, 10, "");
+  Err = Replaces.add(ContainingReplacement);
+  EXPECT_TRUE(!Err);
+  llvm::consumeError(std::move(Err));
+
+  EXPECT_EQ(2u, Replaces.size());
+  EXPECT_EQ(*Replaces.begin(), ContainingReplacement);
+  EXPECT_EQ(*(++Replaces.begin()), After);
+}
+
+TEST_F(ReplacementTest, InsertionBeforeMergedDeletions) {
+  Replacements Replaces;
+
+  Replacement Insertion("x.cc", 0, 0, "123");
+  auto Err = Replaces.add(Insertion);
+  EXPECT_TRUE(!Err);
+  llvm::consumeError(std::move(Err));
+
+  Err = Replaces.add(Replacement("x.cc", 5, 5, ""));
+  EXPECT_TRUE(!Err);
+  llvm::consumeError(std::move(Err));
+
+  Replacement Deletion("x.cc", 0, 10, "");
+  Err = Replaces.add(Deletion);
+  EXPECT_TRUE(!Err);
+  llvm::consumeError(std::move(Err));
+
+  EXPECT_EQ(2u, Replaces.size());
+  EXPECT_EQ(*Replaces.begin(), Insertion);
+  EXPECT_EQ(*(++Replaces.begin()), Deletion);
+}
+
+TEST_F(ReplacementTest, MergeOverlappingDeletions) {
+  Replacements Replaces;
+  auto Err = Replaces.add(Replacement("x.cc", 0, 2, ""));
+  EXPECT_TRUE(!Err);
+  llvm::consumeError(std::move(Err));
+
+  Err = Replaces.add(Replacement("x.cc", 0, 5, ""));
+  EXPECT_TRUE(!Err);
+  llvm::consumeError(std::move(Err));
+
+  EXPECT_EQ(1u, Replaces.size());
+  EXPECT_EQ(Replacement("x.cc", 0, 5, ""), *Replaces.begin());
+
+  Err = Replaces.add(Replacement("x.cc", 1, 5, ""));
+  EXPECT_TRUE(!Err);
+  llvm::consumeError(std::move(Err));
+  EXPECT_EQ(1u, Replaces.size());
+  EXPECT_EQ(Replacement("x.cc", 0, 6, ""), *Replaces.begin());
+}
+
+TEST_F(ReplacementTest, FailedMergeExistingDeletions) {
+  Replacements Replaces;
+  Replacement First("x.cc", 0, 2, "");
+  auto Err = Replaces.add(First);
+  EXPECT_TRUE(!Err);
+  llvm::consumeError(std::move(Err));
+
+  Replacement Second("x.cc", 5, 5, "");
+  Err = Replaces.add(Second);
+  EXPECT_TRUE(!Err);
+  llvm::consumeError(std::move(Err));
+
+  Err = Replaces.add(Replacement("x.cc", 1, 10, ""));
+  EXPECT_TRUE(!Err);
+  llvm::consumeError(std::move(Err));
+
+  EXPECT_EQ(1u, Replaces.size());
+  EXPECT_EQ(Replacement("x.cc", 0, 11, ""), *Replaces.begin());
+}
+
+TEST_F(ReplacementTest, FailAddRegression) {
+  Replacements Replaces;
+  // Create two replacements, where the second one is an insertion of the empty
+  // string exactly at the end of the first one.
+  auto Err = Replaces.add(Replacement("x.cc", 0, 10, "1"));
+  EXPECT_TRUE(!Err);
+  llvm::consumeError(std::move(Err));
+  Err = Replaces.add(Replacement("x.cc", 10, 0, ""));
+  EXPECT_TRUE(!Err);
+  llvm::consumeError(std::move(Err));
+
+  // Make sure we find the overlap with the first entry when inserting a
+  // replacement that ends exactly at the seam of the existing replacements.
+  Replacement OverlappingReplacement("x.cc", 5, 5, "fail");
+  Err = Replaces.add(OverlappingReplacement);
+  EXPECT_TRUE(checkReplacementError(std::move(Err),
+                                    replacement_error::overlap_conflict,
+                                    *Replaces.begin(), OverlappingReplacement));
+
+  Err = Replaces.add(Replacement("x.cc", 10, 0, ""));
+  EXPECT_TRUE(!Err);
+  llvm::consumeError(std::move(Err));
+}
+
+TEST_F(ReplacementTest, InsertAtOffsetOfReplacement) {
+  Replacements Replaces;
+  auto Err = Replaces.add(Replacement("x.cc", 10, 2, ""));
+  EXPECT_TRUE(!Err);
+  llvm::consumeError(std::move(Err));
+  Err = Replaces.add(Replacement("x.cc", 10, 0, ""));
+  EXPECT_TRUE(!Err);
+  llvm::consumeError(std::move(Err));
+  EXPECT_EQ(Replaces.size(), 2u);
+
+  Replaces.clear();
+  Err = Replaces.add(Replacement("x.cc", 10, 0, ""));
+  EXPECT_TRUE(!Err);
+  llvm::consumeError(std::move(Err));
+  Err = Replaces.add(Replacement("x.cc", 10, 2, ""));
+  EXPECT_TRUE(!Err);
+  llvm::consumeError(std::move(Err));
+  EXPECT_EQ(Replaces.size(), 2u);
+}
+
+TEST_F(ReplacementTest, AddInsertAtOtherInsertWhenOderIndependent) {
+  Replacements Replaces;
+  auto Err = Replaces.add(Replacement("x.cc", 10, 0, "a"));
+  EXPECT_TRUE(!Err);
+  llvm::consumeError(std::move(Err));
+  Replacement ConflictInsertion("x.cc", 10, 0, "b");
+  Err = Replaces.add(ConflictInsertion);
+  EXPECT_TRUE(checkReplacementError(std::move(Err),
+                                    replacement_error::insert_conflict,
+                                    *Replaces.begin(), ConflictInsertion));
+
+  Replaces.clear();
+  Err = Replaces.add(Replacement("x.cc", 10, 0, "a"));
+  EXPECT_TRUE(!Err);
+  llvm::consumeError(std::move(Err));
+  Err = Replaces.add(Replacement("x.cc", 10, 0, "aa"));
+  EXPECT_TRUE(!Err);
+  llvm::consumeError(std::move(Err));
+  EXPECT_EQ(1u, Replaces.size());
+  EXPECT_EQ(Replacement("x.cc", 10, 0, "aaa"), *Replaces.begin());
+
+  Replaces.clear();
+  Err = Replaces.add(Replacement("x.cc", 10, 0, ""));
+  EXPECT_TRUE(!Err);
+  llvm::consumeError(std::move(Err));
+  Err = Replaces.add(Replacement("x.cc", 10, 3, ""));
+  EXPECT_TRUE(!Err);
+  llvm::consumeError(std::move(Err));
+  Err = Replaces.add(Replacement("x.cc", 10, 0, ""));
+  EXPECT_TRUE(!Err);
+  llvm::consumeError(std::move(Err));
+  EXPECT_EQ(2u, Replaces.size());
+  EXPECT_EQ(Replacement("x.cc", 10, 0, ""), *Replaces.begin());
+  EXPECT_EQ(Replacement("x.cc", 10, 3, ""), *std::next(Replaces.begin()));
+}
+
+TEST_F(ReplacementTest, InsertBetweenAdjacentReplacements) {
+  Replacements Replaces;
+  auto Err = Replaces.add(Replacement("x.cc", 10, 5, "a"));
+  EXPECT_TRUE(!Err);
+  llvm::consumeError(std::move(Err));
+  Err = Replaces.add(Replacement("x.cc", 8, 2, "a"));
+  EXPECT_TRUE(!Err);
+  llvm::consumeError(std::move(Err));
+  Err = Replaces.add(Replacement("x.cc", 10, 0, "b"));
+  EXPECT_TRUE(!Err);
+  llvm::consumeError(std::move(Err));
+}
+
+TEST_F(ReplacementTest, CanApplyReplacements) {
+  FileID ID = Context.createInMemoryFile("input.cpp",
+                                         "line1\nline2\nline3\nline4");
+  Replacements Replaces =
+      toReplacements({Replacement(Context.Sources,
+                                  Context.getLocation(ID, 2, 1), 5, "replaced"),
+                      Replacement(Context.Sources,
+                                  Context.getLocation(ID, 3, 1), 5, "other")});
+  EXPECT_TRUE(applyAllReplacements(Replaces, Context.Rewrite));
+  EXPECT_EQ("line1\nreplaced\nother\nline4", Context.getRewrittenText(ID));
+}
+
+// Verifies that replacement/deletion is applied before insertion at the same
+// offset.
+TEST_F(ReplacementTest, InsertAndDelete) {
+  FileID ID = Context.createInMemoryFile("input.cpp",
+                                         "line1\nline2\nline3\nline4");
+  Replacements Replaces = toReplacements(
+      {Replacement(Context.Sources, Context.getLocation(ID, 2, 1), 6, ""),
+       Replacement(Context.Sources, Context.getLocation(ID, 2, 1), 0,
+                   "other\n")});
+  EXPECT_TRUE(applyAllReplacements(Replaces, Context.Rewrite));
+  EXPECT_EQ("line1\nother\nline3\nline4", Context.getRewrittenText(ID));
+}
+
+TEST_F(ReplacementTest, AdjacentReplacements) {
+  FileID ID = Context.createInMemoryFile("input.cpp",
+                                         "ab");
+  Replacements Replaces = toReplacements(
+      {Replacement(Context.Sources, Context.getLocation(ID, 1, 1), 1, "x"),
+       Replacement(Context.Sources, Context.getLocation(ID, 1, 2), 1, "y")});
+  EXPECT_TRUE(applyAllReplacements(Replaces, Context.Rewrite));
+  EXPECT_EQ("xy", Context.getRewrittenText(ID));
+}
+
+TEST_F(ReplacementTest, AddDuplicateReplacements) {
+  FileID ID = Context.createInMemoryFile("input.cpp",
+                                         "line1\nline2\nline3\nline4");
+  auto Replaces = toReplacements({Replacement(
+      Context.Sources, Context.getLocation(ID, 2, 1), 5, "replaced")});
+
+  auto Err = Replaces.add(Replacement(
+      Context.Sources, Context.getLocation(ID, 2, 1), 5, "replaced"));
+  EXPECT_TRUE(!Err);
+  llvm::consumeError(std::move(Err));
+
+  Err = Replaces.add(Replacement(Context.Sources, Context.getLocation(ID, 2, 1),
+                                 5, "replaced"));
+  EXPECT_TRUE(!Err);
+  llvm::consumeError(std::move(Err));
+
+  EXPECT_TRUE(applyAllReplacements(Replaces, Context.Rewrite));
+  EXPECT_EQ("line1\nreplaced\nline3\nline4", Context.getRewrittenText(ID));
+}
+
+TEST_F(ReplacementTest, FailOrderDependentReplacements) {
+  FileID ID = Context.createInMemoryFile("input.cpp",
+                                         "line1\nline2\nline3\nline4");
+  auto Replaces = toReplacements({Replacement(
+      Context.Sources, Context.getLocation(ID, 2, 1), 5, "other")});
+
+  Replacement ConflictReplacement(Context.Sources,
+                                  Context.getLocation(ID, 2, 1), 5, "rehto");
+  auto Err = Replaces.add(ConflictReplacement);
+  EXPECT_TRUE(checkReplacementError(std::move(Err),
+                                    replacement_error::overlap_conflict,
+                                    *Replaces.begin(), ConflictReplacement));
+
+  EXPECT_TRUE(applyAllReplacements(Replaces, Context.Rewrite));
+  EXPECT_EQ("line1\nother\nline3\nline4", Context.getRewrittenText(ID));
+}
+
+TEST_F(ReplacementTest, InvalidSourceLocationFailsApplyAll) {
+  Replacements Replaces =
+      toReplacements({Replacement(Context.Sources, SourceLocation(), 5, "2")});
+
+  EXPECT_FALSE(applyAllReplacements(Replaces, Context.Rewrite));
+}
+
+TEST_F(ReplacementTest, MultipleFilesReplaceAndFormat) {
+  // Column limit is 20.
+  std::string Code1 = "Long *a =\n"
+                      "    new Long();\n"
+                      "long x = 1;";
+  std::string Expected1 = "auto a = new Long();\n"
+                          "long x =\n"
+                          "    12345678901;";
+  std::string Code2 = "int x = 123;\n"
+                      "int y = 0;";
+  std::string Expected2 = "int x =\n"
+                          "    1234567890123;\n"
+                          "int y = 10;";
+  StringRef File1 = "format_1.cpp";
+  StringRef File2 = "format_2.cpp";
+  FileID ID1 = Context.createInMemoryFile(File1, Code1);
+  FileID ID2 = Context.createInMemoryFile(File2, Code2);
+
+  // Scrambled the order of replacements.
+  std::map<std::string, Replacements> FileToReplaces;
+  FileToReplaces[File1] = toReplacements(
+      {tooling::Replacement(Context.Sources, Context.getLocation(ID1, 1, 1), 6,
+                            "auto "),
+       tooling::Replacement(Context.Sources, Context.getLocation(ID1, 3, 10), 1,
+                            "12345678901")});
+  FileToReplaces[File2] = toReplacements(
+      {tooling::Replacement(Context.Sources, Context.getLocation(ID2, 1, 12), 0,
+                            "4567890123"),
+       tooling::Replacement(Context.Sources, Context.getLocation(ID2, 2, 9), 1,
+                            "10")});
+  EXPECT_TRUE(
+      formatAndApplyAllReplacements(FileToReplaces, Context.Rewrite,
+                                    "{BasedOnStyle: LLVM, ColumnLimit: 20}"));
+  EXPECT_EQ(Expected1, Context.getRewrittenText(ID1));
+  EXPECT_EQ(Expected2, Context.getRewrittenText(ID2));
+}
+
+TEST(ShiftedCodePositionTest, FindsNewCodePosition) {
+  Replacements Replaces =
+      toReplacements({Replacement("", 0, 1, ""), Replacement("", 4, 3, " ")});
+  // Assume ' int   i;' is turned into 'int i;' and cursor is located at '|'.
+  EXPECT_EQ(0u, Replaces.getShiftedCodePosition(0)); // |int   i;
+  EXPECT_EQ(0u, Replaces.getShiftedCodePosition(1)); //  |nt   i;
+  EXPECT_EQ(1u, Replaces.getShiftedCodePosition(2)); //  i|t   i;
+  EXPECT_EQ(2u, Replaces.getShiftedCodePosition(3)); //  in|   i;
+  EXPECT_EQ(3u, Replaces.getShiftedCodePosition(4)); //  int|  i;
+  EXPECT_EQ(3u, Replaces.getShiftedCodePosition(5)); //  int | i;
+  EXPECT_EQ(3u, Replaces.getShiftedCodePosition(6)); //  int  |i;
+  EXPECT_EQ(4u, Replaces.getShiftedCodePosition(7)); //  int   |;
+  EXPECT_EQ(5u, Replaces.getShiftedCodePosition(8)); //  int   i|
+}
+
+TEST(ShiftedCodePositionTest, FindsNewCodePositionWithInserts) {
+  Replacements Replaces = toReplacements({Replacement("", 4, 0, "\"\n\"")});
+  // Assume '"12345678"' is turned into '"1234"\n"5678"'.
+  EXPECT_EQ(3u, Replaces.getShiftedCodePosition(3)); // "123|5678"
+  EXPECT_EQ(7u, Replaces.getShiftedCodePosition(4)); // "1234|678"
+  EXPECT_EQ(8u, Replaces.getShiftedCodePosition(5)); // "12345|78"
+}
+
+TEST(ShiftedCodePositionTest, FindsNewCodePositionInReplacedText) {
+  // Replace the first four characters with "abcd".
+  auto Replaces = toReplacements({Replacement("", 0, 4, "abcd")});
+  for (unsigned i = 0; i < 3; ++i)
+    EXPECT_EQ(i, Replaces.getShiftedCodePosition(i));
+}
+
+TEST(ShiftedCodePositionTest, NoReplacementText) {
+  Replacements Replaces = toReplacements({Replacement("", 0, 42, "")});
+  EXPECT_EQ(0u, Replaces.getShiftedCodePosition(0));
+  EXPECT_EQ(0u, Replaces.getShiftedCodePosition(39));
+  EXPECT_EQ(3u, Replaces.getShiftedCodePosition(45));
+  EXPECT_EQ(0u, Replaces.getShiftedCodePosition(42));
+}
+
+class FlushRewrittenFilesTest : public ::testing::Test {
+public:
+   FlushRewrittenFilesTest() {}
+
+   ~FlushRewrittenFilesTest() override {
+    for (llvm::StringMap<std::string>::iterator I = TemporaryFiles.begin(),
+                                                E = TemporaryFiles.end();
+         I != E; ++I) {
+      llvm::StringRef Name = I->second;
+      std::error_code EC = llvm::sys::fs::remove(Name);
+      (void)EC;
+      assert(!EC);
+    }
+  }
+
+  FileID createFile(llvm::StringRef Name, llvm::StringRef Content) {
+    SmallString<1024> Path;
+    int FD;
+    std::error_code EC = llvm::sys::fs::createTemporaryFile(Name, "", FD, Path);
+    assert(!EC);
+    (void)EC;
+
+    llvm::raw_fd_ostream OutStream(FD, true);
+    OutStream << Content;
+    OutStream.close();
+    auto File = Context.Files.getFile(Path);
+    assert(File);
+
+    StringRef Found =
+        TemporaryFiles.insert(std::make_pair(Name, Path.str())).first->second;
+    assert(Found == Path);
+    (void)Found;
+    return Context.Sources.createFileID(*File, SourceLocation(),
+                                        SrcMgr::C_User);
+  }
+
+  std::string getFileContentFromDisk(llvm::StringRef Name) {
+    std::string Path = TemporaryFiles.lookup(Name);
+    assert(!Path.empty());
+    // We need to read directly from the FileManager without relaying through
+    // a FileEntry, as otherwise we'd read through an already opened file
+    // descriptor, which might not see the changes made.
+    // FIXME: Figure out whether there is a way to get the SourceManger to
+    // reopen the file.
+    auto FileBuffer = Context.Files.getBufferForFile(Path);
+    return (*FileBuffer)->getBuffer();
+  }
+
+  llvm::StringMap<std::string> TemporaryFiles;
+  RewriterTestContext Context;
+};
+
+TEST_F(FlushRewrittenFilesTest, StoresChangesOnDisk) {
+  FileID ID = createFile("input.cpp", "line1\nline2\nline3\nline4");
+  Replacements Replaces = toReplacements({Replacement(
+      Context.Sources, Context.getLocation(ID, 2, 1), 5, "replaced")});
+  EXPECT_TRUE(applyAllReplacements(Replaces, Context.Rewrite));
+  EXPECT_FALSE(Context.Rewrite.overwriteChangedFiles());
+  EXPECT_EQ("line1\nreplaced\nline3\nline4",
+            getFileContentFromDisk("input.cpp"));
+}
+
+namespace {
+template <typename T>
+class TestVisitor : public clang::RecursiveASTVisitor<T> {
+public:
+  bool runOver(StringRef Code) {
+    return runToolOnCode(std::make_unique<TestAction>(this), Code);
+  }
+
+protected:
+  clang::SourceManager *SM;
+  clang::ASTContext *Context;
+
+private:
+  class FindConsumer : public clang::ASTConsumer {
+  public:
+    FindConsumer(TestVisitor *Visitor) : Visitor(Visitor) {}
+
+    void HandleTranslationUnit(clang::ASTContext &Context) override {
+      Visitor->TraverseDecl(Context.getTranslationUnitDecl());
+    }
+
+  private:
+    TestVisitor *Visitor;
+  };
+
+  class TestAction : public clang::ASTFrontendAction {
+  public:
+    TestAction(TestVisitor *Visitor) : Visitor(Visitor) {}
+
+    std::unique_ptr<clang::ASTConsumer>
+    CreateASTConsumer(clang::CompilerInstance &compiler,
+                      llvm::StringRef dummy) override {
+      Visitor->SM = &compiler.getSourceManager();
+      Visitor->Context = &compiler.getASTContext();
+      /// TestConsumer will be deleted by the framework calling us.
+      return std::make_unique<FindConsumer>(Visitor);
+    }
+
+  private:
+    TestVisitor *Visitor;
+  };
+};
+} // end namespace
+
+void expectReplacementAt(const Replacement &Replace,
+                         StringRef File, unsigned Offset, unsigned Length) {
+  ASSERT_TRUE(Replace.isApplicable());
+  EXPECT_EQ(File, Replace.getFilePath());
+  EXPECT_EQ(Offset, Replace.getOffset());
+  EXPECT_EQ(Length, Replace.getLength());
+}
+
+class ClassDeclXVisitor : public TestVisitor<ClassDeclXVisitor> {
+public:
+  bool VisitCXXRecordDecl(CXXRecordDecl *Record) {
+    if (Record->getName() == "X") {
+      Replace = Replacement(*SM, Record, "");
+    }
+    return true;
+  }
+  Replacement Replace;
+};
+
+TEST(Replacement, CanBeConstructedFromNode) {
+  ClassDeclXVisitor ClassDeclX;
+  EXPECT_TRUE(ClassDeclX.runOver("     class X;"));
+  expectReplacementAt(ClassDeclX.Replace, "input.cc", 5, 7);
+}
+
+TEST(Replacement, ReplacesAtSpellingLocation) {
+  ClassDeclXVisitor ClassDeclX;
+  EXPECT_TRUE(ClassDeclX.runOver("#define A(Y) Y\nA(class X);"));
+  expectReplacementAt(ClassDeclX.Replace, "input.cc", 17, 7);
+}
+
+class CallToFVisitor : public TestVisitor<CallToFVisitor> {
+public:
+  bool VisitCallExpr(CallExpr *Call) {
+    if (Call->getDirectCallee()->getName() == "F") {
+      Replace = Replacement(*SM, Call, "");
+    }
+    return true;
+  }
+  Replacement Replace;
+};
+
+TEST(Replacement, FunctionCall) {
+  CallToFVisitor CallToF;
+  EXPECT_TRUE(CallToF.runOver("void F(); void G() { F(); }"));
+  expectReplacementAt(CallToF.Replace, "input.cc", 21, 3);
+}
+
+TEST(Replacement, TemplatedFunctionCall) {
+  CallToFVisitor CallToF;
+  EXPECT_TRUE(CallToF.runOver(
+        "template <typename T> void F(); void G() { F<int>(); }"));
+  expectReplacementAt(CallToF.Replace, "input.cc", 43, 8);
+}
+
+class NestedNameSpecifierAVisitor
+    : public TestVisitor<NestedNameSpecifierAVisitor> {
+public:
+  bool TraverseNestedNameSpecifierLoc(NestedNameSpecifierLoc NNSLoc) {
+    if (NNSLoc.getNestedNameSpecifier()) {
+      if (const NamespaceDecl* NS = NNSLoc.getNestedNameSpecifier()->getAsNamespace()) {
+        if (NS->getName() == "a") {
+          Replace = Replacement(*SM, &NNSLoc, "", Context->getLangOpts());
+        }
+      }
+    }
+    return TestVisitor<NestedNameSpecifierAVisitor>::TraverseNestedNameSpecifierLoc(
+        NNSLoc);
+  }
+  Replacement Replace;
+};
+
+TEST(Replacement, ColonColon) {
+  NestedNameSpecifierAVisitor VisitNNSA;
+  EXPECT_TRUE(VisitNNSA.runOver("namespace a { void f() { ::a::f(); } }"));
+  expectReplacementAt(VisitNNSA.Replace, "input.cc", 25, 5);
+}
+
+TEST(Range, overlaps) {
+  EXPECT_TRUE(Range(10, 10).overlapsWith(Range(0, 11)));
+  EXPECT_TRUE(Range(0, 11).overlapsWith(Range(10, 10)));
+  EXPECT_FALSE(Range(10, 10).overlapsWith(Range(0, 10)));
+  EXPECT_FALSE(Range(0, 10).overlapsWith(Range(10, 10)));
+  EXPECT_TRUE(Range(0, 10).overlapsWith(Range(2, 6)));
+  EXPECT_TRUE(Range(2, 6).overlapsWith(Range(0, 10)));
+}
+
+TEST(Range, contains) {
+  EXPECT_TRUE(Range(0, 10).contains(Range(0, 10)));
+  EXPECT_TRUE(Range(0, 10).contains(Range(2, 6)));
+  EXPECT_FALSE(Range(2, 6).contains(Range(0, 10)));
+  EXPECT_FALSE(Range(0, 10).contains(Range(0, 11)));
+}
+
+TEST(Range, CalculateRangesOfReplacements) {
+  // Before: aaaabbbbbbz
+  // After : bbbbbbzzzzzzoooooooooooooooo
+  Replacements Replaces = toReplacements(
+      {Replacement("foo", 0, 4, ""), Replacement("foo", 10, 1, "zzzzzz"),
+       Replacement("foo", 11, 0, "oooooooooooooooo")});
+
+  std::vector<Range> Ranges = Replaces.getAffectedRanges();
+
+  EXPECT_EQ(2ul, Ranges.size());
+  EXPECT_TRUE(Ranges[0].getOffset() == 0);
+  EXPECT_TRUE(Ranges[0].getLength() == 0);
+  EXPECT_TRUE(Ranges[1].getOffset() == 6);
+  EXPECT_TRUE(Ranges[1].getLength() == 22);
+}
+
+TEST(Range, CalculateRangesOfInsertionAroundReplacement) {
+  Replacements Replaces = toReplacements(
+      {Replacement("foo", 0, 2, ""), Replacement("foo", 0, 0, "ba")});
+
+  std::vector<Range> Ranges = Replaces.getAffectedRanges();
+
+  EXPECT_EQ(1ul, Ranges.size());
+  EXPECT_EQ(0u, Ranges[0].getOffset());
+  EXPECT_EQ(2u, Ranges[0].getLength());
+}
+
+TEST(Range, RangesAfterEmptyReplacements) {
+  std::vector<Range> Ranges = {Range(5, 6), Range(10, 5)};
+  Replacements Replaces;
+  std::vector<Range> Expected = {Range(5, 10)};
+  EXPECT_EQ(Expected, calculateRangesAfterReplacements(Replaces, Ranges));
+}
+
+TEST(Range, RangesAfterReplacements) {
+  std::vector<Range> Ranges = {Range(5, 2), Range(10, 5)};
+  Replacements Replaces = toReplacements({Replacement("foo", 0, 2, "1234")});
+  std::vector<Range> Expected = {Range(0, 4), Range(7, 2), Range(12, 5)};
+  EXPECT_EQ(Expected, calculateRangesAfterReplacements(Replaces, Ranges));
+}
+
+TEST(Range, RangesBeforeReplacements) {
+  std::vector<Range> Ranges = {Range(5, 2), Range(10, 5)};
+  Replacements Replaces = toReplacements({Replacement("foo", 20, 2, "1234")});
+  std::vector<Range> Expected = {Range(5, 2), Range(10, 5), Range(20, 4)};
+  EXPECT_EQ(Expected, calculateRangesAfterReplacements(Replaces, Ranges));
+}
+
+TEST(Range, NotAffectedByReplacements) {
+  std::vector<Range> Ranges = {Range(0, 2), Range(5, 2), Range(10, 5)};
+  Replacements Replaces = toReplacements({Replacement("foo", 3, 2, "12"),
+                                          Replacement("foo", 12, 2, "12"),
+                                          Replacement("foo", 20, 5, "")});
+  std::vector<Range> Expected = {Range(0, 2), Range(3, 4), Range(10, 5),
+                                 Range(20, 0)};
+  EXPECT_EQ(Expected, calculateRangesAfterReplacements(Replaces, Ranges));
+}
+
+TEST(Range, RangesWithNonOverlappingReplacements) {
+  std::vector<Range> Ranges = {Range(0, 2), Range(5, 2), Range(10, 5)};
+  Replacements Replaces = toReplacements({Replacement("foo", 3, 1, ""),
+                                          Replacement("foo", 6, 1, "123"),
+                                          Replacement("foo", 20, 2, "12345")});
+  std::vector<Range> Expected = {Range(0, 2), Range(3, 0), Range(4, 4),
+                                 Range(11, 5), Range(21, 5)};
+  EXPECT_EQ(Expected, calculateRangesAfterReplacements(Replaces, Ranges));
+}
+
+TEST(Range, RangesWithOverlappingReplacements) {
+  std::vector<Range> Ranges = {Range(0, 2), Range(5, 2), Range(15, 5),
+                               Range(30, 5)};
+  Replacements Replaces = toReplacements(
+      {Replacement("foo", 1, 3, ""), Replacement("foo", 6, 1, "123"),
+       Replacement("foo", 13, 3, "1"), Replacement("foo", 25, 15, "")});
+  std::vector<Range> Expected = {Range(0, 1), Range(2, 4), Range(12, 5),
+                                 Range(22, 0)};
+  EXPECT_EQ(Expected, calculateRangesAfterReplacements(Replaces, Ranges));
+}
+
+TEST(Range, MergeIntoOneRange) {
+  std::vector<Range> Ranges = {Range(0, 2), Range(5, 2), Range(15, 5)};
+  Replacements Replaces =
+      toReplacements({Replacement("foo", 1, 15, "1234567890")});
+  std::vector<Range> Expected = {Range(0, 15)};
+  EXPECT_EQ(Expected, calculateRangesAfterReplacements(Replaces, Ranges));
+}
+
+TEST(Range, ReplacementsStartingAtRangeOffsets) {
+  std::vector<Range> Ranges = {Range(0, 2), Range(5, 5), Range(15, 5)};
+  Replacements Replaces = toReplacements(
+      {Replacement("foo", 0, 2, "12"), Replacement("foo", 5, 1, "123"),
+       Replacement("foo", 7, 4, "12345"), Replacement("foo", 15, 10, "12")});
+  std::vector<Range> Expected = {Range(0, 2), Range(5, 9), Range(18, 2)};
+  EXPECT_EQ(Expected, calculateRangesAfterReplacements(Replaces, Ranges));
+}
+
+TEST(Range, ReplacementsEndingAtRangeEnds) {
+  std::vector<Range> Ranges = {Range(0, 2), Range(5, 2), Range(15, 5)};
+  Replacements Replaces = toReplacements(
+      {Replacement("foo", 6, 1, "123"), Replacement("foo", 17, 3, "12")});
+  std::vector<Range> Expected = {Range(0, 2), Range(5, 4), Range(17, 4)};
+  EXPECT_EQ(Expected, calculateRangesAfterReplacements(Replaces, Ranges));
+}
+
+TEST(Range, AjacentReplacements) {
+  std::vector<Range> Ranges = {Range(0, 0), Range(15, 5)};
+  Replacements Replaces = toReplacements(
+      {Replacement("foo", 1, 2, "123"), Replacement("foo", 12, 3, "1234")});
+  std::vector<Range> Expected = {Range(0, 0), Range(1, 3), Range(13, 9)};
+  EXPECT_EQ(Expected, calculateRangesAfterReplacements(Replaces, Ranges));
+}
+
+TEST(Range, MergeRangesAfterReplacements) {
+  std::vector<Range> Ranges = {Range(8, 0), Range(5, 2), Range(9, 0), Range(0, 1)};
+  Replacements Replaces = toReplacements({Replacement("foo", 1, 3, ""),
+                                          Replacement("foo", 7, 0, "12"),
+                                          Replacement("foo", 9, 2, "")});
+  std::vector<Range> Expected = {Range(0, 1), Range(2, 4), Range(7, 0),
+                                 Range(8, 0)};
+  EXPECT_EQ(Expected, calculateRangesAfterReplacements(Replaces, Ranges));
+}
+
+TEST(Range, ConflictingRangesBeforeReplacements) {
+  std::vector<Range> Ranges = {Range(8, 3), Range(5, 4), Range(9, 1)};
+  Replacements Replaces = toReplacements({Replacement("foo", 1, 3, "")});
+  std::vector<Range> Expected = {Range(1, 0), Range(2, 6)};
+  EXPECT_EQ(Expected, calculateRangesAfterReplacements(Replaces, Ranges));
+}
+
+class MergeReplacementsTest : public ::testing::Test {
+protected:
+  void mergeAndTestRewrite(StringRef Code, StringRef Intermediate,
+                           StringRef Result, const Replacements &First,
+                           const Replacements &Second) {
+    // These are mainly to verify the test itself and make it easier to read.
+    auto AfterFirst = applyAllReplacements(Code, First);
+    EXPECT_TRUE(static_cast<bool>(AfterFirst));
+    auto InSequenceRewrite = applyAllReplacements(*AfterFirst, Second);
+    EXPECT_TRUE(static_cast<bool>(InSequenceRewrite));
+    EXPECT_EQ(Intermediate, *AfterFirst);
+    EXPECT_EQ(Result, *InSequenceRewrite);
+
+    tooling::Replacements Merged = First.merge(Second);
+    auto MergedRewrite = applyAllReplacements(Code, Merged);
+    EXPECT_TRUE(static_cast<bool>(MergedRewrite));
+    EXPECT_EQ(*InSequenceRewrite, *MergedRewrite);
+    if (*InSequenceRewrite != *MergedRewrite)
+      for (tooling::Replacement M : Merged)
+        llvm::errs() << M.getOffset() << " " << M.getLength() << " "
+                     << M.getReplacementText() << "\n";
+  }
+  void mergeAndTestRewrite(StringRef Code, const Replacements &First,
+                           const Replacements &Second) {
+    auto AfterFirst = applyAllReplacements(Code, First);
+    EXPECT_TRUE(static_cast<bool>(AfterFirst));
+    auto InSequenceRewrite = applyAllReplacements(*AfterFirst, Second);
+    tooling::Replacements Merged = First.merge(Second);
+    auto MergedRewrite = applyAllReplacements(Code, Merged);
+    EXPECT_TRUE(static_cast<bool>(MergedRewrite));
+    EXPECT_EQ(*InSequenceRewrite, *MergedRewrite);
+    if (*InSequenceRewrite != *MergedRewrite)
+      for (tooling::Replacement M : Merged)
+        llvm::errs() << M.getOffset() << " " << M.getLength() << " "
+                     << M.getReplacementText() << "\n";
+  }
+};
+
+TEST_F(MergeReplacementsTest, Offsets) {
+  mergeAndTestRewrite("aaa", "aabab", "cacabab",
+                      toReplacements({{"", 2, 0, "b"}, {"", 3, 0, "b"}}),
+                      toReplacements({{"", 0, 0, "c"}, {"", 1, 0, "c"}}));
+  mergeAndTestRewrite("aaa", "babaa", "babacac",
+                      toReplacements({{"", 0, 0, "b"}, {"", 1, 0, "b"}}),
+                      toReplacements({{"", 4, 0, "c"}, {"", 5, 0, "c"}}));
+  mergeAndTestRewrite("aaaa", "aaa", "aac", toReplacements({{"", 1, 1, ""}}),
+                      toReplacements({{"", 2, 1, "c"}}));
+
+  mergeAndTestRewrite("aa", "bbabba", "bbabcba",
+                      toReplacements({{"", 0, 0, "bb"}, {"", 1, 0, "bb"}}),
+                      toReplacements({{"", 4, 0, "c"}}));
+}
+
+TEST_F(MergeReplacementsTest, Concatenations) {
+  // Basic concatenations. It is important to merge these into a single
+  // replacement to ensure the correct order.
+  {
+    auto First = toReplacements({{"", 0, 0, "a"}});
+    auto Second = toReplacements({{"", 1, 0, "b"}});
+    EXPECT_EQ(toReplacements({{"", 0, 0, "ab"}}), First.merge(Second));
+  }
+  {
+    auto First = toReplacements({{"", 0, 0, "a"}});
+    auto Second = toReplacements({{"", 0, 0, "b"}});
+    EXPECT_EQ(toReplacements({{"", 0, 0, "ba"}}), First.merge(Second));
+  }
+  mergeAndTestRewrite("", "a", "ab", toReplacements({{"", 0, 0, "a"}}),
+                      toReplacements({{"", 1, 0, "b"}}));
+  mergeAndTestRewrite("", "a", "ba", toReplacements({{"", 0, 0, "a"}}),
+                      toReplacements({{"", 0, 0, "b"}}));
+}
+
+TEST_F(MergeReplacementsTest, NotChangingLengths) {
+  mergeAndTestRewrite("aaaa", "abba", "acca",
+                      toReplacements({{"", 1, 2, "bb"}}),
+                      toReplacements({{"", 1, 2, "cc"}}));
+  mergeAndTestRewrite("aaaa", "abba", "abcc",
+                      toReplacements({{"", 1, 2, "bb"}}),
+                      toReplacements({{"", 2, 2, "cc"}}));
+  mergeAndTestRewrite("aaaa", "abba", "ccba",
+                      toReplacements({{"", 1, 2, "bb"}}),
+                      toReplacements({{"", 0, 2, "cc"}}));
+  mergeAndTestRewrite("aaaaaa", "abbdda", "abccda",
+                      toReplacements({{"", 1, 2, "bb"}, {"", 3, 2, "dd"}}),
+                      toReplacements({{"", 2, 2, "cc"}}));
+}
+
+TEST_F(MergeReplacementsTest, OverlappingRanges) {
+  mergeAndTestRewrite("aaa", "bbd", "bcbcd",
+                      toReplacements({{"", 0, 1, "bb"}, {"", 1, 2, "d"}}),
+                      toReplacements({{"", 1, 0, "c"}, {"", 2, 0, "c"}}));
+
+  mergeAndTestRewrite("aaaa", "aabbaa", "acccca",
+                      toReplacements({{"", 2, 0, "bb"}}),
+                      toReplacements({{"", 1, 4, "cccc"}}));
+  mergeAndTestRewrite("aaaa", "aababa", "acccca",
+                      toReplacements({{"", 2, 0, "b"}, {"", 3, 0, "b"}}),
+                      toReplacements({{"", 1, 4, "cccc"}}));
+  mergeAndTestRewrite("aaaaaa", "abbbba", "abba",
+                      toReplacements({{"", 1, 4, "bbbb"}}),
+                      toReplacements({{"", 2, 2, ""}}));
+  mergeAndTestRewrite("aaaa", "aa", "cc",
+                      toReplacements({{"", 1, 1, ""}, {"", 2, 1, ""}}),
+                      toReplacements({{"", 0, 2, "cc"}}));
+  mergeAndTestRewrite("aa", "abbba", "abcbcba",
+                      toReplacements({{"", 1, 0, "bbb"}}),
+                      toReplacements({{"", 2, 0, "c"}, {"", 3, 0, "c"}}));
+
+  mergeAndTestRewrite(
+      "aaa", "abbab", "ccdd",
+      toReplacements({{"", 0, 1, ""}, {"", 2, 0, "bb"}, {"", 3, 0, "b"}}),
+      toReplacements({{"", 0, 2, "cc"}, {"", 2, 3, "dd"}}));
+  mergeAndTestRewrite(
+      "aa", "babbab", "ccdd",
+      toReplacements({{"", 0, 0, "b"}, {"", 1, 0, "bb"}, {"", 2, 0, "b"}}),
+      toReplacements({{"", 0, 3, "cc"}, {"", 3, 3, "dd"}}));
+}
+
+TEST(DeduplicateByFileTest, PathsWithDots) {
+  std::map<std::string, Replacements> FileToReplaces;
+  llvm::IntrusiveRefCntPtr<llvm::vfs::InMemoryFileSystem> VFS(
+      new llvm::vfs::InMemoryFileSystem());
+  FileManager FileMgr(FileSystemOptions(), VFS);
+#if !defined(_WIN32)
+  StringRef Path1 = "a/b/.././c.h";
+  StringRef Path2 = "a/c.h";
+#else
+  StringRef Path1 = "a\\b\\..\\.\\c.h";
+  StringRef Path2 = "a\\c.h";
+#endif
+  EXPECT_TRUE(VFS->addFile(Path1, 0, llvm::MemoryBuffer::getMemBuffer("")));
+  EXPECT_TRUE(VFS->addFile(Path2, 0, llvm::MemoryBuffer::getMemBuffer("")));
+  FileToReplaces[Path1] = Replacements();
+  FileToReplaces[Path2] = Replacements();
+  FileToReplaces = groupReplacementsByFile(FileMgr, FileToReplaces);
+  EXPECT_EQ(1u, FileToReplaces.size());
+  EXPECT_EQ(Path1, FileToReplaces.begin()->first);
+}
+
+TEST(DeduplicateByFileTest, PathWithDotSlash) {
+  std::map<std::string, Replacements> FileToReplaces;
+  llvm::IntrusiveRefCntPtr<llvm::vfs::InMemoryFileSystem> VFS(
+      new llvm::vfs::InMemoryFileSystem());
+  FileManager FileMgr(FileSystemOptions(), VFS);
+#if !defined(_WIN32)
+  StringRef Path1 = "./a/b/c.h";
+  StringRef Path2 = "a/b/c.h";
+#else
+  StringRef Path1 = ".\\a\\b\\c.h";
+  StringRef Path2 = "a\\b\\c.h";
+#endif
+  EXPECT_TRUE(VFS->addFile(Path1, 0, llvm::MemoryBuffer::getMemBuffer("")));
+  EXPECT_TRUE(VFS->addFile(Path2, 0, llvm::MemoryBuffer::getMemBuffer("")));
+  FileToReplaces[Path1] = Replacements();
+  FileToReplaces[Path2] = Replacements();
+  FileToReplaces = groupReplacementsByFile(FileMgr, FileToReplaces);
+  EXPECT_EQ(1u, FileToReplaces.size());
+  EXPECT_EQ(Path1, FileToReplaces.begin()->first);
+}
+
+TEST(DeduplicateByFileTest, NonExistingFilePath) {
+  std::map<std::string, Replacements> FileToReplaces;
+  llvm::IntrusiveRefCntPtr<llvm::vfs::InMemoryFileSystem> VFS(
+      new llvm::vfs::InMemoryFileSystem());
+  FileManager FileMgr(FileSystemOptions(), VFS);
+#if !defined(_WIN32)
+  StringRef Path1 = "./a/b/c.h";
+  StringRef Path2 = "a/b/c.h";
+#else
+  StringRef Path1 = ".\\a\\b\\c.h";
+  StringRef Path2 = "a\\b\\c.h";
+#endif
+  FileToReplaces[Path1] = Replacements();
+  FileToReplaces[Path2] = Replacements();
+  FileToReplaces = groupReplacementsByFile(FileMgr, FileToReplaces);
+  EXPECT_TRUE(FileToReplaces.empty());
+}
+
+class AtomicChangeTest : public ::testing::Test {
+  protected:
+    void SetUp() override {
+      DefaultFileID = Context.createInMemoryFile("input.cpp", DefaultCode);
+      DefaultLoc = Context.Sources.getLocForStartOfFile(DefaultFileID)
+                       .getLocWithOffset(20);
+      assert(DefaultLoc.isValid() && "Default location must be valid.");
+    }
+
+    RewriterTestContext Context;
+    std::string DefaultCode = std::string(100, 'a');
+    unsigned DefaultOffset = 20;
+    SourceLocation DefaultLoc;
+    FileID DefaultFileID;
+};
+
+TEST_F(AtomicChangeTest, AtomicChangeToYAML) {
+  AtomicChange Change(Context.Sources, DefaultLoc);
+  llvm::Error Err =
+      Change.insert(Context.Sources, DefaultLoc, "aa", /*InsertAfter=*/false);
+  ASSERT_TRUE(!Err);
+  Err = Change.insert(Context.Sources, DefaultLoc.getLocWithOffset(10), "bb",
+                    /*InsertAfter=*/false);
+  ASSERT_TRUE(!Err);
+  Change.addHeader("a.h");
+  Change.removeHeader("b.h");
+  std::string YAMLString = Change.toYAMLString();
+
+  // NOTE: If this test starts to fail for no obvious reason, check whitespace.
+  ASSERT_STREQ("---\n"
+               "Key:             'input.cpp:20'\n"
+               "FilePath:        input.cpp\n"
+               "Error:           ''\n"
+               "InsertedHeaders:\n"
+               "  - a.h\n"
+               "RemovedHeaders:\n"
+               "  - b.h\n"
+               "Replacements:\n"
+               "  - FilePath:        input.cpp\n"
+               "    Offset:          20\n"
+               "    Length:          0\n"
+               "    ReplacementText: aa\n"
+               "  - FilePath:        input.cpp\n"
+               "    Offset:          30\n"
+               "    Length:          0\n"
+               "    ReplacementText: bb\n"
+               "...\n",
+               YAMLString.c_str());
+}
+
+TEST_F(AtomicChangeTest, YAMLToAtomicChange) {
+  std::string YamlContent = "---\n"
+                            "Key:             'input.cpp:20'\n"
+                            "FilePath:        input.cpp\n"
+                            "Error:           'ok'\n"
+                            "InsertedHeaders:\n"
+                            "  - a.h\n"
+                            "RemovedHeaders:\n"
+                            "  - b.h\n"
+                            "Replacements:\n"
+                            "  - FilePath:        input.cpp\n"
+                            "    Offset:          20\n"
+                            "    Length:          0\n"
+                            "    ReplacementText: aa\n"
+                            "  - FilePath:        input.cpp\n"
+                            "    Offset:          30\n"
+                            "    Length:          0\n"
+                            "    ReplacementText: bb\n"
+                            "...\n";
+  AtomicChange ExpectedChange(Context.Sources, DefaultLoc);
+  llvm::Error Err = ExpectedChange.insert(Context.Sources, DefaultLoc, "aa",
+                                        /*InsertAfter=*/false);
+  ASSERT_TRUE(!Err);
+  Err = ExpectedChange.insert(Context.Sources, DefaultLoc.getLocWithOffset(10),
+                            "bb", /*InsertAfter=*/false);
+  ASSERT_TRUE(!Err);
+
+  ExpectedChange.addHeader("a.h");
+  ExpectedChange.removeHeader("b.h");
+  ExpectedChange.setError("ok");
+
+  AtomicChange ActualChange = AtomicChange::convertFromYAML(YamlContent);
+  EXPECT_EQ(ExpectedChange.getKey(), ActualChange.getKey());
+  EXPECT_EQ(ExpectedChange.getFilePath(), ActualChange.getFilePath());
+  EXPECT_EQ(ExpectedChange.getError(), ActualChange.getError());
+  EXPECT_EQ(ExpectedChange.getInsertedHeaders(),
+            ActualChange.getInsertedHeaders());
+  EXPECT_EQ(ExpectedChange.getRemovedHeaders(),
+            ActualChange.getRemovedHeaders());
+  EXPECT_EQ(ExpectedChange.getReplacements().size(),
+            ActualChange.getReplacements().size());
+  EXPECT_EQ(2u, ActualChange.getReplacements().size());
+  EXPECT_EQ(*ExpectedChange.getReplacements().begin(),
+            *ActualChange.getReplacements().begin());
+  EXPECT_EQ(*(++ExpectedChange.getReplacements().begin()),
+            *(++ActualChange.getReplacements().begin()));
+}
+
+TEST_F(AtomicChangeTest, CheckKeyAndKeyFile) {
+  AtomicChange Change(Context.Sources, DefaultLoc);
+  EXPECT_EQ("input.cpp:20", Change.getKey());
+  EXPECT_EQ("input.cpp", Change.getFilePath());
+}
+
+TEST_F(AtomicChangeTest, Replace) {
+  AtomicChange Change(Context.Sources, DefaultLoc);
+  llvm::Error Err = Change.replace(Context.Sources, DefaultLoc, 2, "aa");
+  ASSERT_TRUE(!Err);
+  EXPECT_EQ(Change.getReplacements().size(), 1u);
+  EXPECT_EQ(*Change.getReplacements().begin(),
+            Replacement(Context.Sources, DefaultLoc, 2, "aa"));
+
+  // Add a new replacement that conflicts with the existing one.
+  Err = Change.replace(Context.Sources, DefaultLoc, 3, "ab");
+  EXPECT_TRUE((bool)Err);
+  llvm::consumeError(std::move(Err));
+  EXPECT_EQ(Change.getReplacements().size(), 1u);
+}
+
+TEST_F(AtomicChangeTest, ReplaceWithRange) {
+  AtomicChange Change(Context.Sources, DefaultLoc);
+  SourceLocation End = DefaultLoc.getLocWithOffset(20);
+  llvm::Error Err = Change.replace(
+      Context.Sources, CharSourceRange::getCharRange(DefaultLoc, End), "aa");
+  ASSERT_TRUE(!Err);
+  EXPECT_EQ(Change.getReplacements().size(), 1u);
+  EXPECT_EQ(*Change.getReplacements().begin(),
+            Replacement(Context.Sources, DefaultLoc, 20, "aa"));
+}
+
+TEST_F(AtomicChangeTest, InsertBefore) {
+  AtomicChange Change(Context.Sources, DefaultLoc);
+  llvm::Error Err = Change.insert(Context.Sources, DefaultLoc, "aa");
+  ASSERT_TRUE(!Err);
+  EXPECT_EQ(Change.getReplacements().size(), 1u);
+  EXPECT_EQ(*Change.getReplacements().begin(),
+            Replacement(Context.Sources, DefaultLoc, 0, "aa"));
+  Err = Change.insert(Context.Sources, DefaultLoc, "b", /*InsertAfter=*/false);
+  ASSERT_TRUE(!Err);
+  EXPECT_EQ(Change.getReplacements().size(), 1u);
+  EXPECT_EQ(*Change.getReplacements().begin(),
+            Replacement(Context.Sources, DefaultLoc, 0, "baa"));
+}
+
+TEST_F(AtomicChangeTest, InsertAfter) {
+  AtomicChange Change(Context.Sources, DefaultLoc);
+  llvm::Error Err = Change.insert(Context.Sources, DefaultLoc, "aa");
+  ASSERT_TRUE(!Err);
+  EXPECT_EQ(Change.getReplacements().size(), 1u);
+  EXPECT_EQ(*Change.getReplacements().begin(),
+            Replacement(Context.Sources, DefaultLoc, 0, "aa"));
+  Err = Change.insert(Context.Sources, DefaultLoc, "b");
+  ASSERT_TRUE(!Err);
+  EXPECT_EQ(Change.getReplacements().size(), 1u);
+  EXPECT_EQ(*Change.getReplacements().begin(),
+            Replacement(Context.Sources, DefaultLoc, 0, "aab"));
+}
+
+TEST_F(AtomicChangeTest, InsertBeforeWithInvalidLocation) {
+  AtomicChange Change(Context.Sources, DefaultLoc);
+  llvm::Error Err =
+      Change.insert(Context.Sources, DefaultLoc, "a", /*InsertAfter=*/false);
+  ASSERT_TRUE(!Err);
+
+  // Invalid location.
+  Err = Change.insert(Context.Sources, SourceLocation(), "a",
+                    /*InsertAfter=*/false);
+  ASSERT_TRUE((bool)Err);
+  EXPECT_TRUE(checkReplacementError(
+      std::move(Err), replacement_error::wrong_file_path,
+      Replacement(Context.Sources, DefaultLoc, 0, "a"),
+      Replacement(Context.Sources, SourceLocation(), 0, "a")));
+}
+
+TEST_F(AtomicChangeTest, InsertBeforeToWrongFile) {
+  AtomicChange Change(Context.Sources, DefaultLoc);
+  llvm::Error Err =
+      Change.insert(Context.Sources, DefaultLoc, "a", /*InsertAfter=*/false);
+  ASSERT_TRUE(!Err);
+
+  // Inserting at a different file.
+  FileID NewID = Context.createInMemoryFile("extra.cpp", DefaultCode);
+  SourceLocation NewLoc = Context.Sources.getLocForStartOfFile(NewID);
+  Err = Change.insert(Context.Sources, NewLoc, "b", /*InsertAfter=*/false);
+  ASSERT_TRUE((bool)Err);
+  EXPECT_TRUE(
+      checkReplacementError(std::move(Err), replacement_error::wrong_file_path,
+                            Replacement(Context.Sources, DefaultLoc, 0, "a"),
+                            Replacement(Context.Sources, NewLoc, 0, "b")));
+}
+
+TEST_F(AtomicChangeTest, InsertAfterWithInvalidLocation) {
+  AtomicChange Change(Context.Sources, DefaultLoc);
+  llvm::Error Err = Change.insert(Context.Sources, DefaultLoc, "a");
+  ASSERT_TRUE(!Err);
+
+  // Invalid location.
+  Err = Change.insert(Context.Sources, SourceLocation(), "b");
+  ASSERT_TRUE((bool)Err);
+  EXPECT_TRUE(checkReplacementError(
+      std::move(Err), replacement_error::wrong_file_path,
+      Replacement(Context.Sources, DefaultLoc, 0, "a"),
+      Replacement(Context.Sources, SourceLocation(), 0, "b")));
+}
+
+class ApplyAtomicChangesTest : public ::testing::Test {
+protected:
+  ApplyAtomicChangesTest() : FilePath("file.cc") {
+    Spec.Cleanup = true;
+    Spec.Format = ApplyChangesSpec::kAll;
+    Spec.Style = format::getLLVMStyle();
+  }
+
+  ~ApplyAtomicChangesTest() override {}
+
+  void setInput(llvm::StringRef Input) {
+    Code = Input;
+    FID = Context.createInMemoryFile(FilePath, Code);
+  }
+
+  SourceLocation getLoc(unsigned Offset) const {
+    return Context.Sources.getLocForStartOfFile(FID).getLocWithOffset(Offset);
+  }
+
+  AtomicChange replacementToAtomicChange(llvm::StringRef Key, unsigned Offset,
+                                         unsigned Length,
+                                         llvm::StringRef Text) {
+    AtomicChange Change(FilePath, Key);
+    llvm::Error Err =
+        Change.replace(Context.Sources, getLoc(Offset), Length, Text);
+    EXPECT_FALSE(Err);
+    return Change;
+  }
+
+  std::string rewrite(bool FailureExpected = false) {
+    llvm::Expected<std::string> ChangedCode =
+        applyAtomicChanges(FilePath, Code, Changes, Spec);
+    EXPECT_EQ(FailureExpected, !ChangedCode);
+    if (!ChangedCode) {
+      llvm::errs() << "Failed to apply changes: "
+                   << llvm::toString(ChangedCode.takeError()) << "\n";
+      return "";
+    }
+    return *ChangedCode;
+  }
+
+  RewriterTestContext Context;
+  FileID FID;
+  ApplyChangesSpec Spec;
+  std::string Code;
+  std::string FilePath;
+  llvm::SmallVector<AtomicChange, 8> Changes;
+};
+
+TEST_F(ApplyAtomicChangesTest, BasicRefactoring) {
+  setInput("int a;");
+  AtomicChange Change(FilePath, "key1");
+  Changes.push_back(replacementToAtomicChange("key1", 4, 1, "b"));
+  EXPECT_EQ("int b;", rewrite());
+}
+
+TEST_F(ApplyAtomicChangesTest, SeveralRefactorings) {
+  setInput("int a;\n"
+           "int b;");
+  Changes.push_back(replacementToAtomicChange("key1", 0, 3, "float"));
+  Changes.push_back(replacementToAtomicChange("key2", 4, 1, "f"));
+  Changes.push_back(replacementToAtomicChange("key3", 11, 1, "g"));
+  Changes.push_back(replacementToAtomicChange("key4", 7, 3, "float"));
+  EXPECT_EQ("float f;\n"
+            "float g;",
+            rewrite());
+}
+
+TEST_F(ApplyAtomicChangesTest, IgnorePathsInRefactorings) {
+  setInput("int a;\n"
+           "int b;");
+  Changes.push_back(replacementToAtomicChange("key1", 4, 1, "aa"));
+
+  FileID ID = Context.createInMemoryFile("AnotherFile", "12345678912345");
+  Changes.emplace_back("AnotherFile", "key2");
+  auto Err = Changes.back().replace(
+      Context.Sources,
+      Context.Sources.getLocForStartOfFile(ID).getLocWithOffset(11), 1, "bb");
+  ASSERT_TRUE(!Err);
+  EXPECT_EQ("int aa;\n"
+            "int bb;",
+            rewrite());
+}
+
+TEST_F(ApplyAtomicChangesTest, AppliesDuplicateInsertions) {
+  setInput("int a;");
+  Changes.push_back(replacementToAtomicChange("key1", 5, 0, "b"));
+  Changes.push_back(replacementToAtomicChange("key2", 5, 0, "b"));
+  EXPECT_EQ("int abb;", rewrite());
+}
+
+TEST_F(ApplyAtomicChangesTest, BailsOnOverlappingRefactorings) {
+  setInput("int a;");
+  Changes.push_back(replacementToAtomicChange("key1", 0, 5, "float f"));
+  Changes.push_back(replacementToAtomicChange("key2", 4, 1, "b"));
+  EXPECT_EQ("", rewrite(/*FailureExpected=*/true));
+}
+
+TEST_F(ApplyAtomicChangesTest, BasicReformatting) {
+  setInput("int  a;");
+  Changes.push_back(replacementToAtomicChange("key1", 5, 1, "b"));
+  EXPECT_EQ("int b;", rewrite());
+}
+
+TEST_F(ApplyAtomicChangesTest, OnlyFormatWhenViolateColumnLimits) {
+  Spec.Format = ApplyChangesSpec::kViolations;
+  Spec.Style.ColumnLimit = 8;
+  setInput("int  a;\n"
+           "int    a;\n"
+           "int  aaaaaaaa;\n");
+  Changes.push_back(replacementToAtomicChange("key1", 5, 1, "x"));
+  Changes.push_back(replacementToAtomicChange("key2", 15, 1, "x"));
+  Changes.push_back(replacementToAtomicChange("key3", 23, 8, "xx"));
+  EXPECT_EQ("int  x;\n"
+            "int x;\n"
+            "int  xx;\n",
+            rewrite());
+}
+
+TEST_F(ApplyAtomicChangesTest, LastLineViolateColumnLimits) {
+  Spec.Format = ApplyChangesSpec::kViolations;
+  Spec.Style.ColumnLimit = 8;
+  setInput("int  a;\n"
+           "int    a;");
+  Changes.push_back(replacementToAtomicChange("key1", 0, 1, "i"));
+  Changes.push_back(replacementToAtomicChange("key2", 15, 2, "y;"));
+  EXPECT_EQ("int  a;\n"
+            "int y;",
+            rewrite());
+}
+
+TEST_F(ApplyAtomicChangesTest, LastLineWithNewlineViolateColumnLimits) {
+  Spec.Format = ApplyChangesSpec::kViolations;
+  Spec.Style.ColumnLimit = 8;
+  setInput("int  a;\n"
+           "int   a;\n");
+  Changes.push_back(replacementToAtomicChange("key1", 0, 1, "i"));
+  Changes.push_back(replacementToAtomicChange("key2", 14, 3, "y;\n"));
+  EXPECT_EQ("int  a;\n"
+            "int   y;\n",
+            rewrite());
+}
+
+TEST_F(ApplyAtomicChangesTest, Longer) {
+  setInput("int  a;");
+  Changes.push_back(replacementToAtomicChange("key1", 5, 1, "bbb"));
+  EXPECT_EQ("int bbb;", rewrite());
+}
+
+TEST_F(ApplyAtomicChangesTest, Shorter) {
+  setInput("int  aaa;");
+  Changes.push_back(replacementToAtomicChange("key1", 5, 3, "b"));
+  EXPECT_EQ("int b;", rewrite());
+}
+
+TEST_F(ApplyAtomicChangesTest, OnlyFormatChangedLines) {
+  setInput("int  aaa;\n"
+           "int a = b;\n"
+           "int  bbb;");
+  Changes.push_back(replacementToAtomicChange("key1", 14, 1, "b"));
+  EXPECT_EQ("int  aaa;\n"
+            "int b = b;\n"
+            "int  bbb;",
+            rewrite());
+}
+
+TEST_F(ApplyAtomicChangesTest, DisableFormatting) {
+  Spec.Format = ApplyChangesSpec::kNone;
+  setInput("int  aaa;\n"
+           "int a   = b;\n"
+           "int  bbb;");
+  Changes.push_back(replacementToAtomicChange("key1", 14, 1, "b"));
+  EXPECT_EQ("int  aaa;\n"
+            "int b   = b;\n"
+            "int  bbb;",
+            rewrite());
+}
+
+TEST_F(ApplyAtomicChangesTest, AdaptsToLocalPointerStyle) {
+  setInput("int *aaa;\n"
+           "int *bbb;");
+  Changes.push_back(replacementToAtomicChange("key1", 0, 0, "int* ccc;\n"));
+  EXPECT_EQ("int *ccc;\n"
+            "int *aaa;\n"
+            "int *bbb;",
+            rewrite());
+}
+
+TEST_F(ApplyAtomicChangesTest, AcceptsSurroundingFormatting) {
+  setInput("   int  aaa;\n"
+           "   int a = b;\n"
+           "   int  bbb;");
+  Changes.push_back(replacementToAtomicChange("key1", 20, 1, "b"));
+  EXPECT_EQ("   int  aaa;\n"
+            "   int b = b;\n"
+            "   int  bbb;",
+            rewrite());
+}
+
+TEST_F(ApplyAtomicChangesTest, BailsOutOnConflictingChanges) {
+  setInput("int c;\n"
+           "int f;");
+  // Insertions at the same offset are only allowed in the same AtomicChange.
+  Changes.push_back(replacementToAtomicChange("key1", 0, 0, "int a;\n"));
+  Changes.push_back(replacementToAtomicChange("key2", 0, 0, "int b;\n"));
+  EXPECT_EQ("", rewrite(/*FailureExpected=*/true));
+}
+
+TEST_F(ApplyAtomicChangesTest, InsertsNewIncludesInRightOrder) {
+  setInput("int a;");
+  Changes.emplace_back(FilePath, "key1");
+  Changes.back().addHeader("b");
+  Changes.back().addHeader("c");
+  Changes.emplace_back(FilePath, "key2");
+  Changes.back().addHeader("a");
+  EXPECT_EQ("#include \"a\"\n"
+            "#include \"b\"\n"
+            "#include \"c\"\n"
+            "int a;",
+            rewrite());
+}
+
+TEST_F(ApplyAtomicChangesTest, RemoveAndSortIncludes) {
+  setInput("#include \"a\"\n"
+           "#include \"b\"\n"
+           "#include \"c\"\n"
+           "\n"
+           "int a;");
+  Changes.emplace_back(FilePath, "key1");
+  Changes.back().removeHeader("b");
+  EXPECT_EQ("#include \"a\"\n"
+            "#include \"c\"\n"
+            "\n"
+            "int a;",
+            rewrite());
+}
+TEST_F(ApplyAtomicChangesTest, InsertsSystemIncludes) {
+  setInput("#include <asys>\n"
+           "#include <csys>\n"
+           "\n"
+           "#include \"a\"\n"
+           "#include \"c\"\n");
+  Changes.emplace_back(FilePath, "key1");
+  Changes.back().addHeader("<asys>"); // Already exists.
+  Changes.back().addHeader("<b>");
+  Changes.back().addHeader("<d>");
+  Changes.back().addHeader("\"b-already-escaped\"");
+  EXPECT_EQ("#include <asys>\n"
+            "#include <b>\n"
+            "#include <csys>\n"
+            "#include <d>\n"
+            "\n"
+            "#include \"a\"\n"
+            "#include \"b-already-escaped\"\n"
+            "#include \"c\"\n",
+            rewrite());
+}
+
+TEST_F(ApplyAtomicChangesTest, RemoveSystemIncludes) {
+  setInput("#include <a>\n"
+           "#include <b>\n"
+           "\n"
+           "#include \"c\""
+           "\n"
+           "int a;");
+  Changes.emplace_back(FilePath, "key1");
+  Changes.back().removeHeader("<a>");
+  EXPECT_EQ("#include <b>\n"
+            "\n"
+            "#include \"c\""
+            "\n"
+            "int a;",
+            rewrite());
+}
+
+TEST_F(ApplyAtomicChangesTest,
+       DoNotFormatFollowingLinesIfSeparatedWithNewline) {
+  setInput("#ifndef __H__\n"
+           "#define __H__\n"
+           "#include \"b\"\n"
+           "\n"
+           "int  a;\n"
+           "int  a;\n"
+           "int  a;\n"
+           "#endif // __H__\n");
+  Changes.push_back(replacementToAtomicChange("key1",
+                                              llvm::StringRef("#ifndef __H__\n"
+                                                              "#define __H__\n"
+                                                              "\n"
+                                                              "#include \"b\"\n"
+                                                              "int  a;\n"
+                                                              "int  ")
+                                                  .size(),
+                                              1, "b"));
+  Changes.back().addHeader("a");
+  EXPECT_EQ("#ifndef __H__\n"
+            "#define __H__\n"
+            "#include \"a\"\n"
+            "#include \"b\"\n"
+            "\n"
+            "int  a;\n"
+            "int b;\n"
+            "int  a;\n"
+            "#endif // __H__\n",
+            rewrite());
+}
+
+TEST_F(ApplyAtomicChangesTest, FormatsCorrectLineWhenHeaderIsRemoved) {
+  setInput("#include \"a\"\n"
+           "\n"
+           "int  a;\n"
+           "int  a;\n"
+           "int  a;");
+  Changes.push_back(replacementToAtomicChange("key1", 27, 1, "b"));
+  Changes.back().removeHeader("a");
+  EXPECT_EQ("\n"
+            "int  a;\n"
+            "int b;\n"
+            "int  a;",
+            rewrite());
+}
+
+TEST_F(ApplyAtomicChangesTest, CleansUpCtorInitializers) {
+  setInput("A::A() : a(), b() {}\n"
+           "A::A() : a(), b() {}\n"
+           "A::A() : a(), b() {}\n"
+           "A::A() : a()/**/, b() {}\n"
+           "A::A() : a()  ,// \n"
+           "   /**/    b()    {}");
+  Changes.emplace_back(FilePath, "key1");
+  auto Err = Changes.back().replace(Context.Sources, getLoc(9), 3, "");
+  ASSERT_TRUE(!Err);
+  Err = Changes.back().replace(Context.Sources, getLoc(35), 3, "");
+  ASSERT_TRUE(!Err);
+  Err = Changes.back().replace(Context.Sources, getLoc(51), 3, "");
+  ASSERT_TRUE(!Err);
+  Err = Changes.back().replace(Context.Sources, getLoc(56), 3, "");
+  ASSERT_TRUE(!Err);
+  Err = Changes.back().replace(Context.Sources, getLoc(72), 3, "");
+  ASSERT_TRUE(!Err);
+  Err = Changes.back().replace(Context.Sources, getLoc(97), 3, "");
+  ASSERT_TRUE(!Err);
+  Err = Changes.back().replace(Context.Sources, getLoc(118), 3, "");
+  ASSERT_TRUE(!Err);
+  EXPECT_EQ("A::A() : b() {}\n"
+            "A::A() : a() {}\n"
+            "A::A() {}\n"
+            "A::A() : b() {}\n"
+            "A::A() {}",
+            rewrite());
+}
+
+TEST_F(ApplyAtomicChangesTest, CleansUpParameterLists) {
+  setInput("void f(int i, float f, string s);\n"
+           "f(1, 2.0f, \"a\");\n"
+           "g(1, 1);");
+  Changes.emplace_back(FilePath, "key1");
+  auto Err = Changes.back().replace(Context.Sources, getLoc(7), 5, "");
+  ASSERT_TRUE(!Err);
+  Err = Changes.back().replace(Context.Sources, getLoc(23), 8, "");
+  ASSERT_TRUE(!Err);
+  Err = Changes.back().replace(Context.Sources, getLoc(36), 1, "");
+  ASSERT_TRUE(!Err);
+  Err = Changes.back().replace(Context.Sources, getLoc(45), 3, "");
+  ASSERT_TRUE(!Err);
+  Err = Changes.back().replace(Context.Sources, getLoc(53), 1, "");
+  ASSERT_TRUE(!Err);
+  Err = Changes.back().replace(Context.Sources, getLoc(56), 1, "");
+  ASSERT_TRUE(!Err);
+  EXPECT_EQ("void f(float f);\n"
+            "f(2.0f);\n"
+            "g();",
+            rewrite());
+}
+
+TEST_F(ApplyAtomicChangesTest, DisableCleanup) {
+  Spec.Cleanup = false;
+  setInput("void f(int i, float f, string s);\n"
+           "f(1, 2.0f, \"a\");\n"
+           "g(1, 1);");
+  Changes.emplace_back(FilePath, "key1");
+  auto Err = Changes.back().replace(Context.Sources, getLoc(7), 5, "");
+  ASSERT_TRUE(!Err);
+  Err = Changes.back().replace(Context.Sources, getLoc(23), 8, "");
+  ASSERT_TRUE(!Err);
+  Err = Changes.back().replace(Context.Sources, getLoc(36), 1, "");
+  ASSERT_TRUE(!Err);
+  Err = Changes.back().replace(Context.Sources, getLoc(45), 3, "");
+  ASSERT_TRUE(!Err);
+  Err = Changes.back().replace(Context.Sources, getLoc(53), 1, "");
+  ASSERT_TRUE(!Err);
+  Err = Changes.back().replace(Context.Sources, getLoc(56), 1, "");
+  ASSERT_TRUE(!Err);
+  EXPECT_EQ("void f(, float f, );\n"
+            "f(, 2.0f, );\n"
+            "g(, );",
+            rewrite());
+}
+
+TEST_F(ApplyAtomicChangesTest, EverythingDeleted) {
+  setInput("int a;");
+  Changes.push_back(replacementToAtomicChange("key1", 0, 6, ""));
+  EXPECT_EQ("", rewrite());
+}
+
+TEST_F(ApplyAtomicChangesTest, DoesNotDeleteInserts) {
+  setInput("int a;\n"
+           "int b;");
+  Changes.emplace_back(FilePath, "key1");
+  auto Err = Changes.back().replace(Context.Sources, getLoc(4), 1, "");
+  ASSERT_TRUE(!Err);
+  Err = Changes.back().replace(Context.Sources, getLoc(4), 0, "b");
+  ASSERT_TRUE(!Err);
+  Err = Changes.back().replace(Context.Sources, getLoc(11), 0, "a");
+  ASSERT_TRUE(!Err);
+  Err = Changes.back().replace(Context.Sources, getLoc(11), 1, "");
+  ASSERT_TRUE(!Err);
+  EXPECT_EQ("int b;\n"
+            "int a;",
+            rewrite());
+}
+
+} // end namespace tooling
+} // end namespace clang