Add support for merging results from plugins

pkg/analysis_server/test/src/plugin/result_merger_test.dart

Index: pkg/analysis_server/test/src/plugin/result_merger_test.dart
diff --git a/pkg/analysis_server/test/src/plugin/result_merger_test.dart b/pkg/analysis_server/test/src/plugin/result_merger_test.dart
new file mode 100644
index 0000000000000000000000000000000000000000..c562e2e62222649957fb68fbdedbcbc5a33a80d0
--- /dev/null
+++ b/pkg/analysis_server/test/src/plugin/result_merger_test.dart
@@ -0,0 +1,698 @@
+// Copyright (c) 2017, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+import 'package:analysis_server/plugin/protocol/protocol.dart';
+import 'package:analysis_server/src/plugin/result_merger.dart';
+import 'package:test/test.dart';
+import 'package:test_reflective_loader/test_reflective_loader.dart';
+
+main() {
+  /*
+    import 'result_merger_test.dart' as result_merger_test;
+    result_merger_test.main();
+   */
+  defineReflectiveSuite(() {
+    defineReflectiveTests(ResultMergerTest);
+  });
+}
+
+@reflectiveTest
+class ResultMergerTest {
+  //
+  // The tests in this class should always perform the merge operation twice
+  // using the same input values in order to ensure that the input values are
+  // not modified by the merge operation.
+  //
+
+  ResultMerger merger = new ResultMerger();
+
+  AnalysisError createError(int offset) {
+    AnalysisErrorSeverity severity = AnalysisErrorSeverity.ERROR;
+    AnalysisErrorType type = AnalysisErrorType.HINT;
+    Location location = new Location('test.dart', offset, 2, 3, 4);
+    return new AnalysisError(severity, type, location, '', '');
+  }
+
+  void test_mergeAnalysisErrorFixes() {
+    AnalysisError error1 = createError(10);
+    AnalysisError error2 = createError(20);
+    AnalysisError error3 = createError(30);
+    AnalysisError error4 = createError(40);
+    SourceChange change1 = new SourceChange('a');
+    SourceChange change2 = new SourceChange('b');
+    SourceChange change3 = new SourceChange('c');
+    SourceChange change4 = new SourceChange('d');
+    SourceChange change5 = new SourceChange('e');
+    AnalysisErrorFixes fix1 = new AnalysisErrorFixes(error1, fixes: [change1]);
+    AnalysisErrorFixes fix2 = new AnalysisErrorFixes(error2, fixes: [change2]);
+    AnalysisErrorFixes fix3 = new AnalysisErrorFixes(error2, fixes: [change3]);
+    AnalysisErrorFixes fix4 = new AnalysisErrorFixes(error3, fixes: [change4]);
+    AnalysisErrorFixes fix5 = new AnalysisErrorFixes(error4, fixes: [change5]);
+    AnalysisErrorFixes fix2and3 =
+        new AnalysisErrorFixes(error2, fixes: [change2, change3]);
+
+    void runTest() {
+      expect(
+          merger.mergeAnalysisErrorFixes([
+            [fix1, fix2],
+            [fix3, fix4],
+            [fix5],
+            []
+          ]),
+          unorderedEquals([fix1, fix2and3, fix4, fix5]));
+    }
+
+    runTest();
+    runTest();
+  }
+
+  void test_mergeAnalysisErrors() {
+    AnalysisError error1 = createError(10);
+    AnalysisError error2 = createError(20);
+    AnalysisError error3 = createError(30);
+    AnalysisError error4 = createError(40);
+
+    void runTest() {
+      expect(
+          merger.mergeAnalysisErrors([
+            [error1, error2],
+            [error3],
+            [],
+            [error4]
+          ]),
+          unorderedEquals([error1, error2, error3, error4]));
+    }
+
+    runTest();
+    runTest();
+  }
+
+  void test_mergeCompletionSuggestions() {
+    CompletionSuggestion createSuggestion(String completion) =>
+        new CompletionSuggestion(CompletionSuggestionKind.IDENTIFIER, 50,
+            completion, 0, 3, false, false);
+
+    CompletionSuggestion suggestion1 = createSuggestion('a');
+    CompletionSuggestion suggestion2 = createSuggestion('b');
+    CompletionSuggestion suggestion3 = createSuggestion('c');
+    CompletionSuggestion suggestion4 = createSuggestion('d');
+
+    void runTest() {
+      expect(
+          merger.mergeCompletionSuggestions([
+            [suggestion1],
+            [suggestion2, suggestion3, suggestion4],
+            []
+          ]),
+          unorderedEquals(
+              [suggestion1, suggestion2, suggestion3, suggestion4]));
+    }
+
+    runTest();
+    runTest();
+  }
+
+  void test_mergeFoldingRegion() {
+    FoldingKind kind = FoldingKind.COMMENT;
+    FoldingRegion region1 = new FoldingRegion(kind, 30, 5);
+    FoldingRegion region2 = new FoldingRegion(kind, 0, 4);
+    FoldingRegion region3 = new FoldingRegion(kind, 20, 6);
+    FoldingRegion region4 = new FoldingRegion(kind, 10, 3);
+    FoldingRegion region5 = new FoldingRegion(kind, 2, 6); // overlaps
+
+    void runTest() {
+      expect(
+          merger.mergeFoldingRegions([
+            [region1, region2],
+            [],
+            [region3],
+            [region4, region5]
+          ]),
+          unorderedEquals([region1, region2, region3, region4]));
+    }
+
+    runTest();
+    runTest();
+  }
+
+  void test_mergeHighlightRegions() {
+    HighlightRegionType type = HighlightRegionType.COMMENT_BLOCK;
+    HighlightRegion region1 = new HighlightRegion(type, 30, 5);
+    HighlightRegion region2 = new HighlightRegion(type, 0, 4);
+    HighlightRegion region3 = new HighlightRegion(type, 20, 6);
+    HighlightRegion region4 = new HighlightRegion(type, 10, 3);
+
+    void runTest() {
+      expect(
+          merger.mergeHighlightRegions([
+            [region1, region2],
+            [],
+            [region3],
+            [region4]
+          ]),
+          unorderedEquals([region1, region2, region3, region4]));
+    }
+
+    runTest();
+    runTest();
+  }
+
+  void test_mergeNavigation() {
+    NavigationTarget target(int fileIndex, int offset) {
+      return new NavigationTarget(
+          ElementKind.CLASS, fileIndex, offset, 1, 0, 0);
+    }
+
+    //
+    // Create the parameters from the server.
+    //
+    NavigationTarget target1_1 = target(0, 1);
+    NavigationTarget target1_2 = target(0, 2);
+    NavigationTarget target2_1 = target(1, 3);
+    NavigationTarget target2_2 = target(1, 4);
+    NavigationRegion region1_1 = new NavigationRegion(10, 4, [0]);
+    NavigationRegion region1_2 = new NavigationRegion(20, 4, [1]);
+    NavigationRegion region2_1 = new NavigationRegion(30, 4, [2]);
+    NavigationRegion region2_2 = new NavigationRegion(40, 4, [3]);
+    AnalysisNavigationParams params1 = new AnalysisNavigationParams(
+        'a.dart',
+        [region1_1, region1_2, region2_1, region2_2],
+        [target1_1, target1_2, target2_1, target2_2],
+        ['one.dart', 'two.dart']);
+    //
+    // Create the parameters from the second plugin.
+    //
+    // same file and offset as target 2_2
+    NavigationTarget target2_3 = target(0, 4);
+    NavigationTarget target2_4 = target(0, 5);
+    NavigationTarget target3_1 = target(1, 6);
+    NavigationTarget target3_2 = target(1, 7);
+    // same region and target as region2_2
+    NavigationRegion region2_3 = new NavigationRegion(40, 4, [0]);
+    // same region as region2_2, but a different target
+    NavigationRegion region2_4 = new NavigationRegion(40, 4, [2]);
+    NavigationRegion region2_5 = new NavigationRegion(50, 4, [1]);
+    NavigationRegion region3_1 = new NavigationRegion(60, 4, [2]);
+    NavigationRegion region3_2 = new NavigationRegion(70, 4, [3]);
+    AnalysisNavigationParams params2 = new AnalysisNavigationParams(
+        'a.dart',
+        [region2_3, region2_4, region2_5, region3_1, region3_2],
+        [target2_3, target2_4, target3_1, target3_2],
+        ['two.dart', 'three.dart']);
+    AnalysisNavigationParams expected = new AnalysisNavigationParams('a.dart', [
+      region1_1,
+      region1_2,
+      region2_1,
+      new NavigationRegion(40, 4, [3, 5]), // union of region2_2 and region2_4
+      new NavigationRegion(50, 4, [4]), // region2_5
+      new NavigationRegion(60, 4, [5]), // region3_1
+      new NavigationRegion(70, 4, [6]), // region3_2
+    ], [
+      target1_1,
+      target1_2,
+      target2_1,
+      target2_2,
+      target(1, 5), // target2_4
+      target(2, 6), // target3_1
+      target(2, 7), // target3_2
+    ], [
+      'one.dart',
+      'two.dart',
+      'three.dart'
+    ]);
+
+    void runTest() {
+      expect(merger.mergeNavigation([params1, params2]), expected);
+    }
+
+    runTest();
+    runTest();
+  }
+
+  void test_mergeOccurrences() {
+    Element element1 = new Element(ElementKind.CLASS, 'e1', 0);
+    Element element2 = new Element(ElementKind.CLASS, 'e2', 0);
+    Element element3 = new Element(ElementKind.CLASS, 'e3', 0);
+    Occurrences occurrence1 = new Occurrences(element1, [1, 2, 4], 2);
+    Occurrences occurrence2 = new Occurrences(element2, [5], 2);
+    Occurrences occurrence3 = new Occurrences(element1, [2, 3], 2);
+    Occurrences occurrence4 = new Occurrences(element3, [8], 2);
+    Occurrences occurrence5 = new Occurrences(element2, [6], 2);
+    Occurrences occurrence6 = new Occurrences(element3, [7, 9], 2);
+    Occurrences result1 = new Occurrences(element1, [1, 2, 3, 4], 2);
+    Occurrences result2 = new Occurrences(element2, [5, 6], 2);
+    Occurrences result3 = new Occurrences(element3, [7, 8, 9], 2);
+
+    void runTest() {
+      expect(
+          merger.mergeOccurrences([
+            [occurrence1, occurrence2],
+            [],
+            [occurrence3, occurrence4],
+            [occurrence5, occurrence6]
+          ]),
+          unorderedEquals([result1, result2, result3]));
+    }
+
+    runTest();
+    runTest();
+  }
+
+  void test_mergeOutline() {
+    Element element(ElementKind kind, int offset) {
+      Location location = new Location('', offset, 0, 0, 0);
+      return new Element(kind, '', 0, location: location);
+    }
+
+    Element element1 = element(ElementKind.CLASS, 100);
+    Element element1_1 = element(ElementKind.METHOD, 110);
+    Element element1_2 = element(ElementKind.METHOD, 120);
+    Element element2 = element(ElementKind.CLASS, 200);
+    Element element2_1 = element(ElementKind.METHOD, 210);
+    Element element2_2 = element(ElementKind.METHOD, 220);
+    Element element3_1 = element(ElementKind.METHOD, 220); // same as 2_2
+    Element element3_2 = element(ElementKind.METHOD, 230);
+    Element element4 = element(ElementKind.CLASS, 300);
+    Element element4_1 = element(ElementKind.METHOD, 310);
+    //
+    // Unique, contributed from first plugin.
+    //
+    // element1
+    // - element1_1
+    // - element1_2
+    //
+    Outline outline1_1 = new Outline(element1_1, 0, 0, children: []);
+    Outline outline1_2 = new Outline(element1_2, 0, 0, children: []);
+    Outline outline1 =
+        new Outline(element1, 0, 0, children: [outline1_1, outline1_2]);
+    //
+    // Same top level element, common child.
+    //
+    // element2
+    // - element2_1
+    // - element2_2
+    // element2
+    // - element3_1
+    // - element3_2
+    //
+    Outline outline2_1 = new Outline(element2_1, 0, 0, children: []);
+    Outline outline2_2 = new Outline(element2_2, 0, 0, children: []);
+    Outline outline3_1 = new Outline(element3_1, 0, 0, children: []);
+    Outline outline3_2 = new Outline(element3_2, 0, 0, children: []);
+    Outline outline2 =
+        new Outline(element2, 0, 0, children: [outline2_1, outline2_2]);
+    Outline outline3 =
+        new Outline(element2, 0, 0, children: [outline3_1, outline3_2]);
+    Outline outline2and3 = new Outline(element2, 0, 0,
+        children: [outline2_1, outline2_2, outline3_2]);
+    //
+    // Unique, contributed from second plugin.
+    //
+    // element4
+    // - element4_1
+    //
+    Outline outline4_1 = new Outline(element4_1, 0, 0, children: []);
+    Outline outline4 = new Outline(element4, 0, 0, children: [outline4_1]);
+
+    void runTest() {
+      expect(
+          merger.mergeOutline([
+            [outline1, outline2],
+            [],
+            [outline3, outline4]
+          ]),
+          unorderedEquals([outline1, outline2and3, outline4]));
+    }
+
+    runTest();
+    runTest();
+  }
+
+  void test_mergeRefactoringFeedbacks_convertGetterToMethodFeedback() {
+    RefactoringFeedback feedback1 = new ConvertGetterToMethodFeedback();
+    RefactoringFeedback feedback2 = new ConvertGetterToMethodFeedback();
+
+    void runTest() {
+      expect(merger.mergeRefactoringFeedbacks([feedback1, feedback2]),
+          equals(feedback1));
+    }
+
+    runTest();
+    runTest();
+  }
+
+  void test_mergeRefactoringFeedbacks_convertMethodToGetterFeedback() {
+    RefactoringFeedback feedback1 = new ConvertMethodToGetterFeedback();
+    RefactoringFeedback feedback2 = new ConvertMethodToGetterFeedback();
+
+    void runTest() {
+      expect(merger.mergeRefactoringFeedbacks([feedback1, feedback2]),
+          equals(feedback1));
+    }
+
+    runTest();
+    runTest();
+  }
+
+  void
+      test_mergeRefactoringFeedbacks_extractLocalVariableFeedback_addEverything() {
+    List<String> names1 = <String>['a', 'b', 'c'];
+    List<int> offsets1 = <int>[10, 20];
+    List<int> lengths1 = <int>[4, 5];
+    List<int> coveringOffsets1 = <int>[100, 150, 200];
+    List<int> coveringLengths1 = <int>[200, 100, 20];
+    RefactoringFeedback feedback1 = new ExtractLocalVariableFeedback(
+        names1, offsets1, lengths1,
+        coveringExpressionOffsets: coveringOffsets1,
+        coveringExpressionLengths: coveringLengths1);
+    List<String> names2 = <String>['c', 'd'];
+    List<int> offsets2 = <int>[30];
+    List<int> lengths2 = <int>[6];
+    List<int> coveringOffsets2 = <int>[210];
+    List<int> coveringLengths2 = <int>[5];
+    RefactoringFeedback feedback2 = new ExtractLocalVariableFeedback(
+        names2, offsets2, lengths2,
+        coveringExpressionOffsets: coveringOffsets2,
+        coveringExpressionLengths: coveringLengths2);
+    List<String> resultNames = <String>['a', 'b', 'c', 'd'];
+    List<int> resultOffsets = new List<int>.from(offsets1)..addAll(offsets2);
+    List<int> resultLengths = new List<int>.from(lengths1)..addAll(lengths2);
+    List<int> resultCoveringOffsets = new List<int>.from(coveringOffsets1)
+      ..addAll(coveringOffsets2);
+    List<int> resultCoveringLengths = new List<int>.from(coveringLengths1)
+      ..addAll(coveringLengths2);
+    RefactoringFeedback result = new ExtractLocalVariableFeedback(
+        resultNames, resultOffsets, resultLengths,
+        coveringExpressionOffsets: resultCoveringOffsets,
+        coveringExpressionLengths: resultCoveringLengths);
+
+    void runTest() {
+      expect(merger.mergeRefactoringFeedbacks([feedback1, feedback2]),
+          equals(result));
+    }
+
+    runTest();
+    runTest();
+  }
+
+  void
+      test_mergeRefactoringFeedbacks_extractLocalVariableFeedback_addOffsetsAndLengths() {
+    List<String> names1 = <String>['a', 'b', 'c'];
+    List<int> offsets1 = <int>[10, 20];
+    List<int> lengths1 = <int>[4, 5];
+    List<int> coveringOffsets1 = <int>[100, 150, 200];
+    List<int> coveringLengths1 = <int>[200, 100, 20];
+    RefactoringFeedback feedback1 = new ExtractLocalVariableFeedback(
+        names1, offsets1, lengths1,
+        coveringExpressionOffsets: coveringOffsets1,
+        coveringExpressionLengths: coveringLengths1);
+    List<String> names2 = <String>[];
+    List<int> offsets2 = <int>[30];
+    List<int> lengths2 = <int>[6];
+    RefactoringFeedback feedback2 =
+        new ExtractLocalVariableFeedback(names2, offsets2, lengths2);
+    List<int> resultOffsets = new List<int>.from(offsets1)..addAll(offsets2);
+    List<int> resultLengths = new List<int>.from(lengths1)..addAll(lengths2);
+    RefactoringFeedback result = new ExtractLocalVariableFeedback(
+        names1, resultOffsets, resultLengths,
+        coveringExpressionOffsets: coveringOffsets1,
+        coveringExpressionLengths: coveringLengths1);
+
+    void runTest() {
+      expect(merger.mergeRefactoringFeedbacks([feedback1, feedback2]),
+          equals(result));
+    }
+
+    runTest();
+    runTest();
+  }
+
+  void
+      test_mergeRefactoringFeedbacks_extractLocalVariableFeedback_noCoverings() {
+    List<String> names1 = <String>['a', 'b', 'c'];
+    List<int> offsets1 = <int>[10, 20];
+    List<int> lengths1 = <int>[4, 5];
+    RefactoringFeedback feedback1 =
+        new ExtractLocalVariableFeedback(names1, offsets1, lengths1);
+    List<String> names2 = <String>[];
+    List<int> offsets2 = <int>[30];
+    List<int> lengths2 = <int>[6];
+    RefactoringFeedback feedback2 =
+        new ExtractLocalVariableFeedback(names2, offsets2, lengths2);
+    List<int> resultOffsets = new List<int>.from(offsets1)..addAll(offsets2);
+    List<int> resultLengths = new List<int>.from(lengths1)..addAll(lengths2);
+    RefactoringFeedback result =
+        new ExtractLocalVariableFeedback(names1, resultOffsets, resultLengths);
+
+    void runTest() {
+      expect(merger.mergeRefactoringFeedbacks([feedback1, feedback2]),
+          equals(result));
+    }
+
+    runTest();
+    runTest();
+  }
+
+  void test_mergeRefactoringFeedbacks_extractMethodFeedback() {
+    int offset1 = 20;
+    int length1 = 5;
+    String returnType1 = 'int';
+    List<String> names1 = <String>['a', 'b', 'c'];
+    bool canCreateGetter1 = false;
+    List<RefactoringMethodParameter> parameters1 =
+        <RefactoringMethodParameter>[];
+    List<int> offsets1 = <int>[10, 20];
+    List<int> lengths1 = <int>[4, 5];
+    RefactoringFeedback feedback1 = new ExtractMethodFeedback(offset1, length1,
+        returnType1, names1, canCreateGetter1, parameters1, offsets1, lengths1);
+    List<String> names2 = <String>['c', 'd'];
+    bool canCreateGetter2 = true;
+    List<RefactoringMethodParameter> parameters2 =
+        <RefactoringMethodParameter>[];
+    List<int> offsets2 = <int>[30];
+    List<int> lengths2 = <int>[6];
+    RefactoringFeedback feedback2 = new ExtractMethodFeedback(
+        0, 0, '', names2, canCreateGetter2, parameters2, offsets2, lengths2);
+    List<String> resultNames = <String>['a', 'b', 'c', 'd'];
+    List<int> resultOffsets = new List<int>.from(offsets1)..addAll(offsets2);
+    List<int> resultLengths = new List<int>.from(lengths1)..addAll(lengths2);
+    RefactoringFeedback result = new ExtractMethodFeedback(
+        offset1,
+        length1,
+        returnType1,
+        resultNames,
+        false,
+        parameters1,
+        resultOffsets,
+        resultLengths);
+
+    void runTest() {
+      expect(merger.mergeRefactoringFeedbacks([feedback1, feedback2]),
+          equals(result));
+    }
+
+    runTest();
+    runTest();
+  }
+
+  void test_mergeRefactoringFeedbacks_inlineLocalVariableFeedback() {
+    RefactoringFeedback feedback1 = new InlineLocalVariableFeedback('a', 2);
+    RefactoringFeedback feedback2 = new InlineLocalVariableFeedback('a', 3);
+    RefactoringFeedback result = new InlineLocalVariableFeedback('a', 5);
+
+    void runTest() {
+      expect(merger.mergeRefactoringFeedbacks([feedback1, feedback2]),
+          equals(result));
+    }
+
+    runTest();
+    runTest();
+  }
+
+  void test_mergeRefactoringFeedbacks_inlineMethodFeedback() {
+    RefactoringFeedback feedback1 = new InlineMethodFeedback('a', false);
+    RefactoringFeedback feedback2 = new InlineMethodFeedback('a', false);
+
+    void runTest() {
+      expect(merger.mergeRefactoringFeedbacks([feedback1, feedback2]),
+          equals(feedback1));
+    }
+
+    runTest();
+    runTest();
+  }
+
+  void test_mergeRefactoringFeedbacks_moveFileFeedback() {
+    RefactoringFeedback feedback1 = new MoveFileFeedback();
+    RefactoringFeedback feedback2 = new MoveFileFeedback();
+
+    void runTest() {
+      expect(merger.mergeRefactoringFeedbacks([feedback1, feedback2]),
+          equals(feedback1));
+    }
+
+    runTest();
+    runTest();
+  }
+
+  void test_mergeRefactoringFeedbacks_renameFeedback() {
+    RefactoringFeedback feedback1 = new RenameFeedback(10, 0, '', '');
+    RefactoringFeedback feedback2 = new RenameFeedback(20, 0, '', '');
+
+    void runTest() {
+      expect(merger.mergeRefactoringFeedbacks([feedback1, feedback2]),
+          equals(feedback1));
+    }
+
+    runTest();
+    runTest();
+  }
+
+  void test_mergeRefactoringKinds() {
+    RefactoringKind kind1 = RefactoringKind.CONVERT_GETTER_TO_METHOD;
+    RefactoringKind kind2 = RefactoringKind.EXTRACT_LOCAL_VARIABLE;
+    RefactoringKind kind3 = RefactoringKind.INLINE_LOCAL_VARIABLE;
+    RefactoringKind kind4 = RefactoringKind.MOVE_FILE;
+    RefactoringKind kind5 = RefactoringKind.EXTRACT_LOCAL_VARIABLE;
+
+    void runTest() {
+      expect(
+          merger.mergeRefactoringKinds([
+            [kind1, kind2],
+            [kind3],
+            [],
+            [kind4, kind5]
+          ]),
+          unorderedEquals([kind1, kind2, kind3, kind4]));
+    }
+
+    runTest();
+    runTest();
+  }
+
+  void test_mergeRefactorings() {
+    RefactoringProblem problem(String message) =>
+        new RefactoringProblem(RefactoringProblemSeverity.ERROR, message);
+    RefactoringProblem problem1 = problem('1');
+    RefactoringProblem problem2 = problem('2');
+    RefactoringProblem problem3 = problem('3');
+    RefactoringProblem problem4 = problem('4');
+    RefactoringProblem problem5 = problem('5');
+    RefactoringProblem problem6 = problem('6');
+
+    List<RefactoringProblem> initialProblems1 = <RefactoringProblem>[
+      problem1,
+      problem2
+    ];
+    List<RefactoringProblem> optionsProblems1 = <RefactoringProblem>[problem3];
+    List<RefactoringProblem> finalProblems1 = <RefactoringProblem>[problem4];
+    RefactoringFeedback feedback1 = new RenameFeedback(10, 0, '', '');
+    SourceFileEdit edit1 =
+        new SourceFileEdit('file1.dart', 11, edits: <SourceEdit>[
+      new SourceEdit(12, 2, 'w', id: 'e1'),
+      new SourceEdit(13, 3, 'x'),
+    ]);
+    SourceChange change1 =
+        new SourceChange('c1', edits: <SourceFileEdit>[edit1]);
+    List<String> potentialEdits1 = <String>['e1'];
+    EditGetRefactoringResult result1 = new EditGetRefactoringResult(
+        initialProblems1, optionsProblems1, finalProblems1,
+        feedback: feedback1, change: change1, potentialEdits: potentialEdits1);
+    List<RefactoringProblem> initialProblems2 = <RefactoringProblem>[problem5];
+    List<RefactoringProblem> optionsProblems2 = <RefactoringProblem>[];
+    List<RefactoringProblem> finalProblems2 = <RefactoringProblem>[problem6];
+    RefactoringFeedback feedback2 = new RenameFeedback(20, 0, '', '');
+    SourceFileEdit edit2 =
+        new SourceFileEdit('file2.dart', 21, edits: <SourceEdit>[
+      new SourceEdit(12, 2, 'y', id: 'e2'),
+      new SourceEdit(13, 3, 'z'),
+    ]);
+    SourceChange change2 =
+        new SourceChange('c2', edits: <SourceFileEdit>[edit2]);
+    List<String> potentialEdits2 = <String>['e2'];
+    EditGetRefactoringResult result2 = new EditGetRefactoringResult(
+        initialProblems2, optionsProblems2, finalProblems2,
+        feedback: feedback2, change: change2, potentialEdits: potentialEdits2);
+    List<RefactoringProblem> mergedInitialProblems = <RefactoringProblem>[
+      problem1,
+      problem2,
+      problem5
+    ];
+    List<RefactoringProblem> mergedOptionsProblems = <RefactoringProblem>[
+      problem3
+    ];
+    List<RefactoringProblem> mergedFinalProblems = <RefactoringProblem>[
+      problem4,
+      problem6
+    ];
+    SourceChange mergedChange =
+        new SourceChange('c1', edits: <SourceFileEdit>[edit1, edit2]);
+    List<String> mergedPotentialEdits = <String>['e1', 'e2'];
+    EditGetRefactoringResult mergedResult = new EditGetRefactoringResult(
+        mergedInitialProblems, mergedOptionsProblems, mergedFinalProblems,
+        feedback: merger.mergeRefactoringFeedbacks([feedback1, feedback2]),
+        change: mergedChange,
+        potentialEdits: mergedPotentialEdits);
+
+    void runTest() {
+      expect(merger.mergeRefactorings([result1, result2]), mergedResult);
+    }
+
+    runTest();
+    runTest();
+  }
+
+  void test_mergeSourceChanges() {
+    SourceChange kind1 = new SourceChange('');
+    SourceChange kind2 = new SourceChange('');
+    SourceChange kind3 = new SourceChange('');
+    SourceChange kind4 = new SourceChange('');
+
+    void runTest() {
+      expect(
+          merger.mergeSourceChanges([
+            [kind1, kind2],
+            [],
+            [kind3],
+            [kind4]
+          ]),
+          unorderedEquals([kind1, kind2, kind3, kind4]));
+    }
+
+    runTest();
+    runTest();
+  }
+
+  void test_overlaps_false_nested_left() {
+    expect(merger.overlaps(3, 5, 1, 7, allowNesting: true), isFalse);
+  }
+
+  void test_overlaps_false_nested_right() {
+    expect(merger.overlaps(1, 7, 3, 5, allowNesting: true), isFalse);
+  }
+
+  void test_overlaps_false_onLeft() {
+    expect(merger.overlaps(1, 3, 5, 7), isFalse);
+  }
+
+  void test_overlaps_false_onRight() {
+    expect(merger.overlaps(5, 7, 1, 3), isFalse);
+  }
+
+  void test_overlaps_true_nested_left() {
+    expect(merger.overlaps(3, 5, 1, 7), isTrue);
+  }
+
+  void test_overlaps_true_nested_right() {
+    expect(merger.overlaps(1, 7, 3, 5), isTrue);
+  }
+
+  void test_overlaps_true_onLeft() {
+    expect(merger.overlaps(1, 5, 3, 7), isTrue);
+  }
+
+  void test_overlaps_true_onRight() {
+    expect(merger.overlaps(3, 7, 1, 5), isTrue);
+  }
+}