Initial 'Extract Method' refactoring implementation.

pkg/analysis_server/test/services/refactoring/extract_method_test.dart

+// Copyright (c) 2014, 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.
+
+library test.services.refactoring.extract_method;
+
+import 'dart:async';
+
+import 'package:analysis_server/src/protocol2.dart';
+import 'package:analysis_server/src/services/refactoring/extract_method.dart';
+import 'package:analysis_testing/reflective_tests.dart';
+import 'package:unittest/unittest.dart';
+
+import 'abstract_refactoring.dart';
+
+
+main() {
+  groupSep = ' | ';
+  runReflectiveTests(ExtractMethodTest);
+}
+
+
+@ReflectiveTestCase()
+class ExtractMethodTest extends RefactoringTest {
+  ExtractMethodRefactoringImpl refactoring;
+
+  test_bad_assignmentLeftHandSide() {
+    indexTestUnit('''
+main() {
+  int aaa;
+  aaa = 0;
+}
+''');
+    _createRefactoringForString('aaa ');
+    return _assertConditionsFatal(
+        'Cannot extract the left-hand side of an assignment.');
+  }
+
+  test_bad_comment_selectionEndsInside() {
+    indexTestUnit('''
+main() {
+// start
+  print(0);
+/*
+// end
+*/
+}
+''');
+    _createRefactoringForStartEndComments();
+    return _assertConditionsFatal('Selection ends inside a comment.');
+  }
+
+  test_bad_comment_selectionStartsInside() {
+    indexTestUnit('''
+main() {
+/*
+// start
+*/
+  print(0);
+// end
+}
+''');
+    _createRefactoringForStartEndComments();
+    return _assertConditionsFatal('Selection begins inside a comment.');
+  }
+
+  test_bad_conflict_method_alreadyDeclaresMethod() {
+    indexTestUnit('''
+class A {
+  void res() {}
+  main() {
+// start
+    print(0);
+// end
+  }
+}
+''');
+    _createRefactoringForStartEndComments();
+    // TODO(scheglov) implement
+//    return _assertConditionsError("Class 'A' already declares method with name 'res'.");
+  }
+
+  test_bad_conflict_method_shadowsSuperDeclaration() {
+    indexTestUnit('''
+class A {
+  void res() {} // marker
+}
+class B extends A {
+  main() {
+    res();
+// start
+    print(0);
+// end
+  }
+}
+''');
+    _createRefactoringForStartEndComments();
+    // TODO(scheglov) implement
+//    return _assertConditionsError("Created method will shadow method 'A.res'.");
+  }
+
+  test_bad_conflict_topLevel_alreadyDeclaresFunction() {
+    indexTestUnit('''
+void res() {}
+main() {
+// start
+  print(0);
+// end
+}
+''');
+    _createRefactoringForStartEndComments();
+    // TODO(scheglov) implement
+//    return _assertConditionsError("Library already declares function with name 'res'.");
+  }
+
+  test_bad_conflict_topLevel_willHideInheritedMemberUsage() {
+    indexTestUnit('''
+class A {
+  void res() {}
+}
+class B extends A {
+  foo() {
+    res(); // marker
+  }
+}
+main() {
+// start
+  print(0);
+// end
+}
+''');
+    _createRefactoringForStartEndComments();
+    // TODO(scheglov) implement
+//    return _assertConditionsError("Created function will shadow method 'A.res'.");
+  }
+
+  test_bad_constructor_initializer() {
+    indexTestUnit('''
+class A {
+  int f;
+  A() : f = 0 {}
+}
+''');
+    _createRefactoringForString('f = 0');
+    return _assertConditionsFatal(
+        'Cannot extract a constructor initializer. Select expression part of initializer.');
+  }
+
+  test_bad_constructor_redirectingConstructor() {
+    indexTestUnit('''
+class A {
+  A() : this.named();
+  A.named() {}
+}
+''');
+    _createRefactoringForString('this.named()');
+    return _assertConditionsFatal(
+        'Cannot extract a constructor initializer. Select expression part of initializer.');
+  }
+
+  test_bad_constructor_superConstructor() {
+    indexTestUnit('''
+class A {}
+class B extends A {
+  B() : super();
+}
+''');
+    _createRefactoringForString('super()');
+    return _assertConditionsFatal(
+        'Cannot extract a constructor initializer. Select expression part of initializer.');
+  }
+
+  test_bad_doWhile_body() {
+    indexTestUnit('''
+main() {
+  do 
+// start
+  { 
+  }
+// end
+  while (true);
+}
+''');
+    _createRefactoringForStartEndComments();
+    return _assertConditionsFatal(
+        "Operation not applicable to a 'do' statement's body and expression.");
+  }
+
+  test_bad_emptySelection() {
+    indexTestUnit('''
+main() {
+// start
+// end
+  print(0);
+}
+''');
+    _createRefactoringForStartEndComments();
+    return _assertConditionsFatal(
+        "Can only extract a single expression or a set of statements.");
+  }
+
+  test_bad_forLoop_conditionAndUpdaters() {
+    indexTestUnit('''
+main() {
+  for ( 
+    int i = 0;
+// start
+    i < 10; 
+    i++
+// end
+  ) {}
+}
+''');
+    _createRefactoringForStartEndComments();
+    return _assertConditionsFatal(
+        "Operation not applicable to a 'for' statement's condition and updaters.");
+  }
+
+  test_bad_forLoop_init() {
+    indexTestUnit('''
+main() {
+  for ( 
+// start
+    int i = 0
+// end
+    ; i < 10;
+    i++
+  ) {}
+}
+''');
+    _createRefactoringForStartEndComments();
+    return _assertConditionsFatal(
+        "Cannot extract initialization part of a 'for' statement.");
+  }
+
+  test_bad_forLoop_initAndCondition() {
+    indexTestUnit('''
+main() {
+  for ( 
+// start
+    int i = 0;
+    i < 10;
+// end
+    i++
+  ) {}
+}
+''');
+    _createRefactoringForStartEndComments();
+    return _assertConditionsFatal(
+        "Operation not applicable to a 'for' statement's initializer and condition.");
+  }
+
+  test_bad_forLoop_updaters() {
+    indexTestUnit('''
+main() {
+  for ( 
+    int i = 0;
+    i < 10;
+// start
+    i++
+// end
+  ) {}
+}
+''');
+    _createRefactoringForStartEndComments();
+    return _assertConditionsFatal(
+        "Cannot extract increment part of a 'for' statement.");
+  }
+
+  test_bad_forLoop_updatersAndBody() {
+    indexTestUnit('''
+main() {
+  for ( 
+    int i = 0;
+    i < 10;
+// start
+    i++
+  ) {}
+// end
+}
+''');
+    _createRefactoringForStartEndComments();
+    return _assertConditionsFatal(
+        "Operation not applicable to a 'for' statement's updaters and body.");
+  }
+
+  test_bad_methodName_reference() {
+    indexTestUnit('''
+main() {
+  main();
+}
+''');
+    _createRefactoringWithSuffix('main', '();');
+    return _assertConditionsFatal("Cannot extract a single method name.");
+  }
+
+  test_bad_namePartOfDeclaration_function() {
+    indexTestUnit('''
+main() {
+}
+''');
+    _createRefactoringForString('main');
+    return _assertConditionsFatal(
+        "Cannot extract the name part of a declaration.");
+  }
+
+  test_bad_namePartOfDeclaration_variable() {
+    indexTestUnit('''
+main() {
+  int vvv = 0;
+}
+''');
+    _createRefactoringForString('vvv');
+    return _assertConditionsFatal(
+        "Cannot extract the name part of a declaration.");
+  }
+
+  test_bad_namePartOfQualified() {
+    indexTestUnit('''
+class A {
+  var fff;
+}
+main() {
+  A a;
+  a.fff = 1;
+}
+''');
+    _createRefactoringWithSuffix('fff', ' = 1');
+    return _assertConditionsFatal(
+        "Can not extract name part of a property access.");
+  }
+
+  test_bad_newMethodName_notIdentifier() {
+    indexTestUnit('''
+main() {
+// start
+  print(0);
+// end
+}
+''');
+    _createRefactoringForStartEndComments();
+    refactoring.name = 'bad-name';
+    // TODO(scheglov) implement
+//    return _assertConditionsFatal("Method name must not contain '-'.");
+  }
+
+  test_bad_notSameParent() {
+    indexTestUnit('''
+main() {
+  while (false) 
+// start
+  { 
+  } 
+  print(0);
+// end
+}
+''');
+    _createRefactoringForStartEndComments();
+    return _assertConditionsFatal(
+        'Not all selected statements are enclosed by the same parent statement.');
+  }
+
+  test_bad_parameterName_duplicate() {
+    indexTestUnit('''
+main() {
+  int v1 = 1;
+  int v2 = 2;
+// start
+  int a = v1 + v2; // marker
+// end
+}
+''');
+    _createRefactoringForStartEndComments();
+    // TODO(scheglov) implement
+    // update parameters
+//    {
+//      Parameter[] parameters = refactoring.getParameters();
+//      assertThat(parameters).hasSize(2);
+//      parameters[0].setNewName("dup");
+//      parameters[1].setNewName("dup");
+//      refactoring.setParameters(parameters);
+//    }
+//    // check conditions
+//    refactoringStatus = refactoring.checkFinalConditions(pm);
+//    assertRefactoringStatus(
+//        refactoringStatus,
+//        RefactoringStatusSeverity.ERROR,
+//        "Parameter 'dup' already exists");
+  }
+
+  test_bad_parameterName_inUse() {
+    indexTestUnit('''
+main() {
+  int v1 = 1;
+  int v2 = 2;
+// start
+  int a = v1 + v2; // marker
+// end
+}
+''');
+    _createRefactoringForStartEndComments();
+    // TODO(scheglov) implement
+    // update parameters
+//    {
+//      Parameter[] parameters = refactoring.getParameters();
+//      assertThat(parameters).hasSize(2);
+//      parameters[0].setNewName("a");
+//      refactoring.setParameters(parameters);
+//    }
+//    // check conditions
+//    refactoringStatus = refactoring.checkFinalConditions(pm);
+//    assertRefactoringStatus(
+//        refactoringStatus,
+//        RefactoringStatusSeverity.ERROR,
+//        "'a' is already used as a name in the selected code");
+  }
+
+  test_bad_selectionEndsInSomeNode() {
+    indexTestUnit('''
+main() {
+// start
+  print(0);
+  print(1);
+// end
+}
+''');
+    _createRefactoringForStartEndString('print(0', 'int(1)');
+    return _assertConditionsFatal(
+        "The selection does not cover a set of statements or an expression. "
+            "Extend selection to a valid range.");
+  }
+
+  test_bad_statements_return_andAssignsVariable() {
+    indexTestUnit('''
+main() {
+// start
+  var v = 0;
+  return 42;
+// end
+  print(v);
+}
+''');
+    _createRefactoringForStartEndComments();
+    return _assertConditionsFatal(
+        "Ambiguous return value: Selected block contains assignment(s) to "
+            "local variables and return statement.");
+  }
+
+  test_bad_switchCase() {
+    indexTestUnit('''
+main() {
+  switch (1) { 
+// start
+    case 0: break;
+// end
+  }
+}
+''');
+    _createRefactoringForStartEndComments();
+    return _assertConditionsFatal(
+        "Selection must either cover whole switch statement "
+            "or parts of a single case block.");
+  }
+
+  test_bad_tokensBetweenLastNodeAndSelectionEnd() {
+    indexTestUnit('''
+main() {
+// start
+  print(0);
+  print(1);
+}
+// end
+''');
+    _createRefactoringForStartEndComments();
+    return _assertConditionsFatal(
+        "The end of the selection contains characters that do not belong to a statement.");
+  }
+
+  test_bad_tokensBetweenSelectionStartAndFirstNode() {
+    indexTestUnit('''
+main() {
+// start
+  print(0); // marker
+  print(1);
+// end
+}
+''');
+    _createRefactoringForStartEndString('); // marker', '// end');
+    return _assertConditionsFatal(
+        "The beginning of the selection contains characters that do not belong to a statement.");
+  }
+
+  test_bad_try_catchBlock_block() {
+    indexTestUnit('''
+main() {
+  try
+  {} 
+  catch (e)
+// start
+  {}
+// end
+}
+''');
+    _createRefactoringForStartEndComments();
+    return _assertConditionsFatal(
+        "Selection must either cover whole try statement or "
+            "parts of try, catch, or finally block.");
+  }
+
+  test_bad_try_catchBlock_complete() {
+    indexTestUnit('''
+main() {
+  try
+  {} 
+// start
+  catch (e)
+  {}
+// end
+}
+''');
+    _createRefactoringForStartEndComments();
+    return _assertConditionsFatal(
+        "Selection must either cover whole try statement or "
+            "parts of try, catch, or finally block.");
+  }
+
+  test_bad_try_catchBlock_exception() {
+    indexTestUnit('''
+main() {
+  try {
+  } catch ( 
+// start
+  e
+// end
+  ) {
+  }
+}
+''');
+    _createRefactoringForStartEndComments();
+    return _assertConditionsFatal(
+        'Cannot extract the name part of a declaration.');
+  }
+
+  test_bad_try_finallyBlock() {
+    indexTestUnit('''
+main() {
+  try
+  {} 
+  finally
+// start
+  {}
+// end
+}
+''');
+    _createRefactoringForStartEndComments();
+    return _assertConditionsFatal(
+        "Selection must either cover whole try statement or "
+            "parts of try, catch, or finally block.");
+  }
+
+  test_bad_try_tryBlock() {
+    indexTestUnit('''
+main() {
+  try
+// start
+  {} 
+// end
+  finally
+  {}
+}
+''');
+    _createRefactoringForStartEndComments();
+    return _assertConditionsFatal(
+        "Selection must either cover whole try statement or "
+            "parts of try, catch, or finally block.");
+  }
+
+  test_bad_typeReference() {
+    indexTestUnit('''
+main() {
+  int a = 0;
+}
+''');
+    _createRefactoringForString("int");
+    return _assertConditionsFatal(
+        "Cannot extract a single type reference.");
+  }
+
+  test_bad_variableDeclarationFragment() {
+    indexTestUnit('''
+main() {
+  int 
+// start
+    a = 1
+// end
+    ,b = 2;
+}
+''');
+    _createRefactoringForStartEndComments();
+    return _assertConditionsFatal(
+        "Cannot extract a variable declaration fragment. Select whole declaration statement.");
+  }
+
+  test_bad_while_conditionAndBody() {
+    indexTestUnit('''
+main() {
+  while 
+// start
+    (false) 
+  { 
+  } 
+// end
+}
+''');
+    _createRefactoringForStartEndComments();
+    return _assertConditionsFatal(
+        "Operation not applicable to a while statement's expression and body.");
+  }
+
+  test_canExtractGetter_false_fieldAssignment() {
+    indexTestUnit('''
+class A {
+  var f;
+  main() {
+// start
+    f = 1;
+// end
+  }
+}
+''');
+    _createRefactoringForStartEndComments();
+    // apply refactoring
+    return assertRefactoringConditionsOK().then((_) {
+      expect(refactoring.canCreateGetter, false);
+      expect(refactoring.createGetter, false);
+    });
+  }
+
+  test_canExtractGetter_false_hasParameters() {
+    indexTestUnit('''
+main(int p) {
+  int a = p + 1;
+}
+''');
+    _createRefactoringForString('p + 1');
+    // apply refactoring
+    return assertRefactoringConditionsOK().then((_) {
+      expect(refactoring.canCreateGetter, false);
+      expect(refactoring.createGetter, false);
+    });
+  }
+
+  test_canExtractGetter_false_returnNotUsed_assignment() {
+    indexTestUnit('''
+var topVar = 0;
+f(int p) {
+  topVar = 5;
+}
+''');
+    _createRefactoringForString('topVar = 5');
+    // apply refactoring
+    return assertRefactoringConditionsOK().then((_) {
+      expect(refactoring.canCreateGetter, false);
+      expect(refactoring.createGetter, false);
+    });
+  }
+
+  test_canExtractGetter_false_returnNotUsed_noReturn() {
+    indexTestUnit('''
+var topVar = 0;
+main() {
+// start
+  int a = 1;
+  int b = 2;
+  topVar = a + b;
+// end
+}
+''');
+    _createRefactoringForStartEndComments();
+    // apply refactoring
+    return assertRefactoringConditionsOK().then((_) {
+      expect(refactoring.canCreateGetter, false);
+      expect(refactoring.createGetter, false);
+    });
+  }
+
+  test_canExtractGetter_true() {
+    indexTestUnit('''
+main() {
+  int a = 1 + 2;
+}
+''');
+    _createRefactoringForString('1 + 2');
+    // apply refactoring
+    return assertRefactoringConditionsOK().then((_) {
+      expect(refactoring.canCreateGetter, true);
+      expect(refactoring.createGetter, true);
+    });
+  }
+
+  test_checkName() {
+    indexTestUnit('''
+main() {
+  int a = 1 + 2;
+}
+''');
+    _createRefactoringForString('1 + 2');
+    // null
+    refactoring.name = null;
+    assertRefactoringStatus(
+        refactoring.checkName(),
+        RefactoringProblemSeverity.FATAL,
+        expectedMessage: "Method name must not be null.");
+    // empty
+    refactoring.name = '';
+    assertRefactoringStatus(
+        refactoring.checkName(),
+        RefactoringProblemSeverity.FATAL,
+        expectedMessage: "Method name must not be empty.");
+    // OK
+    refactoring.name = 'res';
+    assertRefactoringStatusOK(refactoring.checkName());
+  }
+
+  test_closure_asFunction_singleExpression() {
+    indexTestUnit('''
+process(f(x)) {}
+main() {
+  process((x) => x * 2);
+}
+''');
+    _createRefactoringForString('(x) => x * 2');
+    // apply refactoring
+    return _assertSuccessfulRefactoring('''
+process(f(x)) {}
+main() {
+  process(res);
+}
+
+res(x) => x * 2;
+''');
+  }
+
+  test_closure_asFunction_statements() {
+    indexTestUnit('''
+process(f(x)) {}
+main() {
+  process((x) {
+    print(x);
+    return x * 2;
+  }); // marker
+}
+''');
+    _createRefactoringForStartEndString('(x) {', '); // marker');
+    // apply refactoring
+    return _assertSuccessfulRefactoring('''
+process(f(x)) {}
+main() {
+  process(res); // marker
+}
+
+res(x) {
+  print(x);
+  return x * 2;
+}
+''');
+  }
+
+  test_closure_asMethod_statements() {
+    indexTestUnit('''
+process(f(x)) {}
+class A {
+  int k = 2;
+  main() {
+    process((x) {
+      print(x);
+      return x * k;
+    }); // marker
+  }
+}
+''');
+    _createRefactoringForStartEndString('(x) {', '); // marker');
+    // apply refactoring
+    return _assertSuccessfulRefactoring('''
+process(f(x)) {}
+class A {
+  int k = 2;
+  main() {
+    process(res); // marker
+  }
+
+  res(x) {
+    print(x);
+    return x * k;
+  }
+}
+''');
+  }
+
+  test_closure_bad_referencesLocalVariable() {
+    indexTestUnit('''
+process(f(x)) {}
+main() {
+  int k = 2;
+  process((x) => x * k);
+}
+''');
+    _createRefactoringForString('(x) => x * k');
+    // check
+    return refactoring.checkInitialConditions().then((status) {
+      assertRefactoringStatus(
+          status,
+          RefactoringProblemSeverity.FATAL,
+          expectedMessage:
+              'Cannot extract closure as method, it references 1 external variable(s).');
+    });
+  }
+
+  test_closure_bad_referencesParameter() {
+    indexTestUnit('''
+process(f(x)) {}
+main(int k) {
+  process((x) => x * k);
+}
+''');
+    _createRefactoringForString('(x) => x * k');
+    // check
+    return refactoring.checkInitialConditions().then((status) {
+      assertRefactoringStatus(
+          status,
+          RefactoringProblemSeverity.FATAL,
+          expectedMessage:
+              'Cannot extract closure as method, it references 1 external variable(s).');
+    });
+  }
+
+  test_fromTopLevelVariableInitializerClosure() {
+    indexTestUnit('''
+var X = 1;
+
+var Y = () {
+  return 1 + X;
+};
+''');
+    _createRefactoringForString('1 + X');
+    // apply refactoring
+    return _assertSuccessfulRefactoring('''
+var X = 1;
+
+var Y = () {
+  return res();
+};
+
+num res() => 1 + X;
+''');
+  }
+
+  test_getExtractGetter_false_do() {
+    indexTestUnit('''
+main() {
+// start
+  int v = 0;
+  do {
+    v++;
+  } while (v < 10);
+// end
+  print(v);
+}
+''');
+    _createRefactoringForStartEndComments();
+    // apply refactoring
+    return assertRefactoringConditionsOK().then((_) {
+      expect(refactoring.createGetter, false);
+    });
+  }
+
+  test_getExtractGetter_false_for() {
+    indexTestUnit('''
+main() {
+// start
+  int v = 0;
+  for (int i = 0; i < 10; i++) {
+    v += i;
+  }
+// end
+  print(v);
+}
+''');
+    _createRefactoringForStartEndComments();
+    // apply refactoring
+    return assertRefactoringConditionsOK().then((_) {
+      expect(refactoring.createGetter, false);
+    });
+  }
+
+  test_getExtractGetter_false_forEach() {
+    indexTestUnit('''
+main() {
+// start
+  int v = 0;
+  for (int i in [1, 2, 3]) {
+    v += i;
+  }
+// end
+  print(v);
+}
+''');
+    _createRefactoringForStartEndComments();
+    // apply refactoring
+    return assertRefactoringConditionsOK().then((_) {
+      expect(refactoring.createGetter, false);
+    });
+  }
+
+  test_getExtractGetter_false_methodInvocation_expression() {
+    indexTestUnit('''
+main() {
+  int v = calculateSomething() + 5;
+}
+int calculateSomething() => 42;
+''');
+    _createRefactoringForString('calculateSomething() + 5');
+    // apply refactoring
+    return assertRefactoringConditionsOK().then((_) {
+      expect(refactoring.createGetter, false);
+    });
+  }
+
+  test_getExtractGetter_false_methodInvocation_statements() {
+    indexTestUnit('''
+main() {
+// start
+  int v = calculateSomething();
+// end
+  print(v);
+}
+int calculateSomething() => 42;
+''');
+    _createRefactoringForStartEndComments();
+    // apply refactoring
+    return assertRefactoringConditionsOK().then((_) {
+      expect(refactoring.createGetter, false);
+    });
+  }
+
+  test_getExtractGetter_false_while() {
+    indexTestUnit('''
+main() {
+// start
+  int v = 0;
+  while (v < 10) {
+    v++;
+  }
+// end
+  print(v);
+}
+''');
+    _createRefactoringForStartEndComments();
+    // apply refactoring
+    return assertRefactoringConditionsOK().then((_) {
+      expect(refactoring.createGetter, false);
+    });
+  }
+
+  test_getExtractGetter_true_simpleBlock() {
+    indexTestUnit('''
+main() {
+// start
+  int v = 1 + 2;
+// end
+  print(v);
+}
+''');
+    _createRefactoringForStartEndComments();
+    // apply refactoring
+    return assertRefactoringConditionsOK().then((_) {
+      expect(refactoring.createGetter, true);
+    });
+  }
+
+  test_getExtractGetter_true_singleExpression() {
+    indexTestUnit('''
+main() {
+// start
+  int v = 1 + 2;
+// end
+  print(v);
+}
+''');
+    _createRefactoringForString('1 + 2');
+    // apply refactoring
+    return assertRefactoringConditionsOK().then((_) {
+      expect(refactoring.createGetter, true);
+    });
+  }
+
+  test_getRefactoringName_function() {
+    indexTestUnit('''
+main() {
+  print(1 + 2);
+}
+''');
+    _createRefactoringForString('1 + 2');
+    expect(refactoring.refactoringName, 'Extract Function');
+  }
+
+  test_getRefactoringName_method() {
+    indexTestUnit('''
+class A {
+  main() {
+    print(1 + 2);
+  }
+}
+''');
+    _createRefactoringForString('1 + 2');
+    expect(refactoring.refactoringName, 'Extract Method');
+  }
+
+  test_setExtractGetter() {
+    indexTestUnit('''
+main() {
+  int a = 1 + 2;
+}
+''');
+    _createRefactoringForString('1 + 2');
+    // apply refactoring
+    return assertRefactoringConditionsOK().then((_) {
+      expect(refactoring.canCreateGetter, true);
+      expect(refactoring.createGetter, true);
+      return refactoring.createChange().then((SourceChange refactoringChange) {
+        this.refactoringChange = refactoringChange;
+        assertTestChangeResult('''
+main() {
+  int a = res;
+}
+
+int get res => 1 + 2;
+''');
+      });
+    });
+  }
+
+  test_singleExpression() {
+    indexTestUnit('''
+main() {
+  int a = 1 + 2;
+}
+''');
+    _createRefactoringForString('1 + 2');
+    // apply refactoring
+    return _assertSuccessfulRefactoring('''
+main() {
+  int a = res();
+}
+
+int res() => 1 + 2;
+''');
+  }
+
+  test_singleExpression_cascade() {
+    indexTestUnit('''
+main() {
+  String s = '';
+  var v = s..length;
+}
+''');
+    _createRefactoringForString('s..length');
+    // apply refactoring
+    return _assertSuccessfulRefactoring('''
+main() {
+  String s = '';
+  var v = res(s);
+}
+
+String res(String s) => s..length;
+''');
+  }
+
+  test_singleExpression_dynamic() {
+    indexTestUnit('''
+dynaFunction() {}
+main() {
+  var v = dynaFunction(); // marker
+}
+''');
+    _createRefactoringWithSuffix('dynaFunction()', '; // marker');
+    // apply refactoring
+    return _assertSuccessfulRefactoring('''
+dynaFunction() {}
+main() {
+  var v = res(); // marker
+}
+
+res() => dynaFunction();
+''');
+  }
+
+  test_singleExpression_ignore_assignmentLeftHandSize() {
+    indexTestUnit('''
+main() {
+  getButton().text = 'txt';
+  print(getButton().text); // marker
+}
+getButton() {}
+''');
+    _createRefactoringWithSuffix('getButton().text', '); // marker');
+    // apply refactoring
+    return _assertSuccessfulRefactoring('''
+main() {
+  getButton().text = 'txt';
+  print(res()); // marker
+}
+
+res() => getButton().text;
+getButton() {}
+''');
+  }
+
+  test_singleExpression_occurrences() {
+    indexTestUnit('''
+main() {
+  int v1 = 1;
+  int v2 = 2;
+  int v3 = 3;
+  int positiveA = v1 + v2; // marker
+  int positiveB = v2 + v3;
+  int positiveC = v1 +  v2;
+  int positiveD = v1/*abc*/ + v2;
+  int negA = 1 + 2;
+  int negB = 1 + v2;
+  int negC = v1 + 2;
+  int negD = v1 * v2;
+}
+''');
+    _createRefactoringWithSuffix('v1 + v2', '; // marker');
+    // apply refactoring
+    return _assertSuccessfulRefactoring('''
+main() {
+  int v1 = 1;
+  int v2 = 2;
+  int v3 = 3;
+  int positiveA = res(v1, v2); // marker
+  int positiveB = res(v2, v3);
+  int positiveC = res(v1, v2);
+  int positiveD = res(v1, v2);
+  int negA = 1 + 2;
+  int negB = 1 + v2;
+  int negC = v1 + 2;
+  int negD = v1 * v2;
+}
+
+int res(int v1, int v2) => v1 + v2;
+''');
+  }
+
+  test_singleExpression_occurrences_disabled() {
+    indexTestUnit('''
+main() {
+  int v1 = 1;
+  int v2 = 2;
+  int v3 = 3;
+  int a = v1 + v2; // marker
+  int b = v2 + v3;
+}
+''');
+    _createRefactoringWithSuffix('v1 + v2', '; // marker');
+    refactoring.extractAll = false;
+    // apply refactoring
+    return _assertSuccessfulRefactoring('''
+main() {
+  int v1 = 1;
+  int v2 = 2;
+  int v3 = 3;
+  int a = res(v1, v2); // marker
+  int b = v2 + v3;
+}
+
+int res(int v1, int v2) => v1 + v2;
+''');
+  }
+
+  test_singleExpression_occurrences_inClassOnly() {
+    indexTestUnit('''
+class A {
+  myMethod() {
+    int v1 = 1;
+    int v2 = 2;
+    int positiveA = v1 + v2; // marker
+  }
+}
+main() {
+  int v1 = 1;
+  int v2 = 2;
+  int negA = v1 + v2;
+}
+''');
+    _createRefactoringWithSuffix('v1 + v2', '; // marker');
+    // apply refactoring
+    return _assertSuccessfulRefactoring('''
+class A {
+  myMethod() {
+    int v1 = 1;
+    int v2 = 2;
+    int positiveA = res(v1, v2); // marker
+  }
+
+  int res(int v1, int v2) => v1 + v2;
+}
+main() {
+  int v1 = 1;
+  int v2 = 2;
+  int negA = v1 + v2;
+}
+''');
+  }
+
+  test_singleExpression_occurrences_inWholeUnit() {
+    indexTestUnit('''
+main() {
+  int v1 = 1;
+  int v2 = 2;
+  int positiveA = v1 + v2; // marker
+}
+class A {
+  myMethod() {
+    int v1 = 1;
+    int v2 = 2;
+    int positiveB = v1 + v2;
+  }
+}
+''');
+    _createRefactoringWithSuffix('v1 + v2', '; // marker');
+    // apply refactoring
+    return _assertSuccessfulRefactoring('''
+main() {
+  int v1 = 1;
+  int v2 = 2;
+  int positiveA = res(v1, v2); // marker
+}
+
+int res(int v1, int v2) => v1 + v2;
+class A {
+  myMethod() {
+    int v1 = 1;
+    int v2 = 2;
+    int positiveB = res(v1, v2);
+  }
+}
+''');
+  }
+
+  test_singleExpression_returnTypeGeneric() {
+    indexTestUnit('''
+main() {
+  var v = new List<String>();
+}
+''');
+    _createRefactoringForString('new List<String>()');
+    // apply refactoring
+    return _assertSuccessfulRefactoring('''
+main() {
+  var v = res();
+}
+
+List<String> res() => new List<String>();
+''');
+  }
+
+  test_singleExpression_returnTypePrefix() {
+    indexTestUnit('''
+import 'dart:math' as pref;
+main() {
+  var v = new pref.Random();
+}
+''');
+    _createRefactoringForString('new pref.Random()');
+    // apply refactoring
+    return _assertSuccessfulRefactoring('''
+import 'dart:math' as pref;
+main() {
+  var v = res();
+}
+
+pref.Random res() => new pref.Random();
+''');
+  }
+
+  test_singleExpression_staticContext_extractFromInitializer() {
+    indexTestUnit('''
+class A {
+  A(int v) {}
+}
+class B extends A {
+  B() : super(1 + 2) {}
+}
+''');
+    _createRefactoringForString('1 + 2');
+    // apply refactoring
+    return _assertSuccessfulRefactoring('''
+class A {
+  A(int v) {}
+}
+class B extends A {
+  B() : super(res()) {}
+
+  static int res() => 1 + 2;
+}
+''');
+  }
+
+  test_singleExpression_staticContext_extractFromInstance() {
+    indexTestUnit('''
+class A {
+  instanceMethodA() {
+    int v1 = 1;
+    int v2 = 2;
+    int positiveA = v1 + v2; // marker
+  }
+  instanceMethodB() {
+    int v1 = 1;
+    int v2 = 2;
+    int positiveB = v1 + v2;
+  }
+  static staticMethodA() {
+    int v1 = 1;
+    int v2 = 2;
+    int positiveA = v1 + v2;
+  }
+}
+''');
+    _createRefactoringWithSuffix('v1 + v2', '; // marker');
+    // apply refactoring
+    return _assertSuccessfulRefactoring('''
+class A {
+  instanceMethodA() {
+    int v1 = 1;
+    int v2 = 2;
+    int positiveA = res(v1, v2); // marker
+  }
+
+  static int res(int v1, int v2) => v1 + v2;
+  instanceMethodB() {
+    int v1 = 1;
+    int v2 = 2;
+    int positiveB = res(v1, v2);
+  }
+  static staticMethodA() {
+    int v1 = 1;
+    int v2 = 2;
+    int positiveA = res(v1, v2);
+  }
+}
+''');
+  }
+
+  test_singleExpression_staticContext_extractFromStatic() {
+    indexTestUnit('''
+class A {
+  static staticMethodA() {
+    int v1 = 1;
+    int v2 = 2;
+    int positiveA = v1 + v2; // marker
+  }
+  static staticMethodB() {
+    int v1 = 1;
+    int v2 = 2;
+    int positiveB = v1 + v2;
+  }
+  instanceMethodA() {
+    int v1 = 1;
+    int v2 = 2;
+    int positiveA = v1 + v2;
+  }
+}
+''');
+    _createRefactoringWithSuffix('v1 + v2', '; // marker');
+    // apply refactoring
+    return _assertSuccessfulRefactoring('''
+class A {
+  static staticMethodA() {
+    int v1 = 1;
+    int v2 = 2;
+    int positiveA = res(v1, v2); // marker
+  }
+
+  static int res(int v1, int v2) => v1 + v2;
+  static staticMethodB() {
+    int v1 = 1;
+    int v2 = 2;
+    int positiveB = res(v1, v2);
+  }
+  instanceMethodA() {
+    int v1 = 1;
+    int v2 = 2;
+    int positiveA = res(v1, v2);
+  }
+}
+''');
+  }
+
+  test_singleExpression_staticContext_hasInInitializer() {
+    indexTestUnit('''
+class A {
+  A(int v) {}
+}
+class B extends A {
+  B() : super(1 + 2) {}
+  foo() {
+    print(1 + 2); // marker
+  }
+}
+''');
+    _createRefactoringWithSuffix('1 + 2', '); // marker');
+    // apply refactoring
+    return _assertSuccessfulRefactoring('''
+class A {
+  A(int v) {}
+}
+class B extends A {
+  B() : super(res()) {}
+  foo() {
+    print(res()); // marker
+  }
+
+  static int res() => 1 + 2;
+}
+''');
+  }
+
+  test_singleExpression_usesParameter() {
+    indexTestUnit('''
+fooA(int a1) {
+  int a2 = 2;
+  int a = a1 + a2;
+}
+fooB(int b1) {
+  int b2 = 2;
+  int b = b1 + b2;
+}
+''');
+    _createRefactoringForString('a1 + a2');
+    // apply refactoring
+    return _assertSuccessfulRefactoring('''
+fooA(int a1) {
+  int a2 = 2;
+  int a = res(a1, a2);
+}
+
+int res(int a1, int a2) => a1 + a2;
+fooB(int b1) {
+  int b2 = 2;
+  int b = res(b1, b2);
+}
+''');
+  }
+
+  test_singleExpression_withVariables() {
+    indexTestUnit('''
+main() {
+  int v1 = 1;
+  int v2 = 2;
+  int a = v1 + v2 + v1;
+}
+''');
+    _createRefactoringForString('v1 + v2 + v1');
+    // apply refactoring
+    return _assertSuccessfulRefactoring('''
+main() {
+  int v1 = 1;
+  int v2 = 2;
+  int a = res(v1, v2);
+}
+
+int res(int v1, int v2) => v1 + v2 + v1;
+''');
+  }
+
+  test_singleExpression_withVariables_doRename() {
+    // TODO(scheglov)
+  }
+
+  test_singleExpression_withVariables_doReorder() {
+    // TODO(scheglov)
+  }
+
+  test_singleExpression_withVariables_namedExpression() {
+    indexTestUnit('''
+main() {
+  int v1 = 1;
+  int v2 = 2;
+  int a = process(arg: v1 + v2);
+}
+process({arg}) {}
+''');
+    _createRefactoringForString('process(arg: v1 + v2)');
+    // apply refactoring
+    return _assertSuccessfulRefactoring('''
+main() {
+  int v1 = 1;
+  int v2 = 2;
+  int a = res(v1, v2);
+}
+
+res(int v1, int v2) => process(arg: v1 + v2);
+process({arg}) {}
+''');
+  }
+
+  test_singleExpression_withVariables_newType() {
+    // TODO(scheglov)
+  }
+
+  test_singleExpression_withVariables_useBestType() {
+    indexTestUnit('''
+main() {
+  var v1 = 1;
+  var v2 = 2;
+  var a = v1 + v2 + v1; // marker
+}
+''');
+    _createRefactoringForString('v1 + v2 + v1');
+    // apply refactoring
+    return _assertSuccessfulRefactoring('''
+main() {
+  var v1 = 1;
+  var v2 = 2;
+  var a = res(v1, v2); // marker
+}
+
+num res(int v1, int v2) => v1 + v2 + v1;
+''');
+  }
+
+  test_statements_assignment() {
+    indexTestUnit('''
+main() {
+  int v;
+// start
+  v = 5;
+// end
+  print(v);
+}
+''');
+    _createRefactoringForStartEndComments();
+    // apply refactoring
+    return _assertSuccessfulRefactoring('''
+main() {
+  int v;
+// start
+  v = res(v);
+// end
+  print(v);
+}
+
+int res(int v) {
+  v = 5;
+  return v;
+}
+''');
+  }
+
+  test_statements_changeIndentation() {
+    indexTestUnit('''
+main() {
+  {
+// start
+    if (true) {
+      print(0);
+    }
+// end
+  }
+}
+''');
+    _createRefactoringForStartEndComments();
+    // apply refactoring
+    return _assertSuccessfulRefactoring('''
+main() {
+  {
+// start
+    res();
+// end
+  }
+}
+
+void res() {
+  if (true) {
+    print(0);
+  }
+}
+''');
+  }
+
+  test_statements_changeIndentation_multilineString() {
+    indexTestUnit('''
+main() {
+  {
+// start
+    print("""
+first line
+second line
+    """);
+// end
+  }
+}
+''');
+    _createRefactoringForStartEndComments();
+    // apply refactoring
+    return _assertSuccessfulRefactoring('''
+main() {
+  {
+// start
+    res();
+// end
+  }
+}
+
+void res() {
+  print("""
+first line
+second line
+    """);
+}
+''');
+  }
+
+  test_statements_definesVariable_notUsedOutside() {
+    indexTestUnit('''
+main() {
+  int a = 1;
+  int b = 1;
+// start
+  int v = a + b;
+  print(v);
+// end
+}
+''');
+    _createRefactoringForStartEndComments();
+    // apply refactoring
+    return _assertSuccessfulRefactoring('''
+main() {
+  int a = 1;
+  int b = 1;
+// start
+  res(a, b);
+// end
+}
+
+void res(int a, int b) {
+  int v = a + b;
+  print(v);
+}
+''');
+  }
+
+  test_statements_definesVariable_oneUsedOutside_assignment() {
+    indexTestUnit('''
+myFunctionA() {
+  int a = 1;
+// start
+  a += 10;
+// end
+  print(a);
+}
+myFunctionB() {
+  int b = 2;
+  b += 10;
+  print(b);
+}
+''');
+    _createRefactoringForStartEndComments();
+    // apply refactoring
+    return _assertSuccessfulRefactoring('''
+myFunctionA() {
+  int a = 1;
+// start
+  a = res(a);
+// end
+  print(a);
+}
+
+int res(int a) {
+  a += 10;
+  return a;
+}
+myFunctionB() {
+  int b = 2;
+  b = res(b);
+  print(b);
+}
+''');
+  }
+
+  test_statements_definesVariable_oneUsedOutside_declaration() {
+    indexTestUnit('''
+myFunctionA() {
+  int a = 1;
+  int b = 2;
+// start
+  int v1 = a + b;
+// end
+  print(v1);
+}
+myFunctionB() {
+  int a = 3;
+  int b = 4;
+  int v2 = a + b;
+  print(v2);
+}
+''');
+    _createRefactoringForStartEndComments();
+    // apply refactoring
+    return _assertSuccessfulRefactoring('''
+myFunctionA() {
+  int a = 1;
+  int b = 2;
+// start
+  int v1 = res(a, b);
+// end
+  print(v1);
+}
+
+int res(int a, int b) {
+  int v1 = a + b;
+  return v1;
+}
+myFunctionB() {
+  int a = 3;
+  int b = 4;
+  int v2 = res(a, b);
+  print(v2);
+}
+''');
+  }
+
+  test_statements_definesVariable_twoUsedOutside() {
+    indexTestUnit('''
+main() {
+// start
+  int varA = 1;
+  int varB = 2;
+// end
+  int v = varA + varB;
+}
+''');
+    _createRefactoringForStartEndComments();
+    // check conditions
+    return refactoring.checkInitialConditions().then((status) {
+      assertRefactoringStatus(status, RefactoringProblemSeverity.FATAL);
+    });
+  }
+
+  test_statements_duplicate_absolutelySame() {
+    indexTestUnit('''
+myFunctionA() {
+  print(0);
+  print(1);
+}
+myFunctionB() {
+// start
+  print(0);
+  print(1);
+// end
+}
+''');
+    _createRefactoringForStartEndComments();
+    // apply refactoring
+    return _assertSuccessfulRefactoring('''
+myFunctionA() {
+  res();
+}
+myFunctionB() {
+// start
+  res();
+// end
+}
+
+void res() {
+  print(0);
+  print(1);
+}
+''');
+  }
+
+  test_statements_duplicate_declaresDifferentlyNamedVariable() {
+    indexTestUnit('''
+myFunctionA() {
+  int varA = 1;
+  print(varA);
+}
+myFunctionB() {
+// start
+  int varB = 1;
+  print(varB);
+// end
+}
+''');
+    _createRefactoringForStartEndComments();
+    // apply refactoring
+    return _assertSuccessfulRefactoring('''
+myFunctionA() {
+  res();
+}
+myFunctionB() {
+// start
+  res();
+// end
+}
+
+void res() {
+  int varB = 1;
+  print(varB);
+}
+''');
+  }
+
+  test_statements_dynamic() {
+    indexTestUnit('''
+dynaFunction(p) => 0;
+main() {
+// start
+  var a = 1;
+  var v = dynaFunction(a);
+// end
+  print(v);
+}
+''');
+    _createRefactoringForStartEndComments();
+    // apply refactoring
+    return _assertSuccessfulRefactoring('''
+dynaFunction(p) => 0;
+main() {
+// start
+  var v = res();
+// end
+  print(v);
+}
+
+res() {
+  var a = 1;
+  var v = dynaFunction(a);
+  return v;
+}
+''');
+  }
+
+  /**
+   * We should always add ";" when invoke method with extracted statements.
+   */
+  test_statements_endsWithBlock() {
+    indexTestUnit('''
+main() {
+// start
+  if (true) {
+    print(0);
+  }
+// end
+}
+''');
+    _createRefactoringForStartEndComments();
+    // apply refactoring
+    return _assertSuccessfulRefactoring('''
+main() {
+// start
+  res();
+// end
+}
+
+void res() {
+  if (true) {
+    print(0);
+  }
+}
+''');
+  }
+
+  test_statements_inSwitchMember() {
+    indexTestUnit('''
+class A {
+  foo(int p) {
+    switch (p) {
+      case 0:
+// start
+        print(0);
+// end
+        break;
+      default:
+        break;
+    }
+  }
+}
+''');
+    _createRefactoringForStartEndComments();
+    // apply refactoring
+    return _assertSuccessfulRefactoring('''
+class A {
+  foo(int p) {
+    switch (p) {
+      case 0:
+// start
+        res();
+// end
+        break;
+      default:
+        break;
+    }
+  }
+
+  void res() {
+    print(0);
+  }
+}
+''');
+  }
+
+  test_statements_method() {
+    indexTestUnit('''
+class A {
+  foo() {
+// start
+    print(0);
+// end
+  }
+}
+''');
+    _createRefactoringForStartEndComments();
+    // apply refactoring
+    return _assertSuccessfulRefactoring('''
+class A {
+  foo() {
+// start
+    res();
+// end
+  }
+
+  void res() {
+    print(0);
+  }
+}
+''');
+  }
+
+  test_statements_noDuplicates() {
+    indexTestUnit('''
+main() {
+  int a = 1;
+  int b = 1;
+// start
+  print(a);
+// end
+}
+''');
+    _createRefactoringForStartEndComments();
+    // apply refactoring
+    return _assertSuccessfulRefactoring('''
+main() {
+  int a = 1;
+  int b = 1;
+// start
+  res(a);
+// end
+}
+
+void res(int a) {
+  print(a);
+}
+''');
+  }
+
+  test_statements_return_last() {
+    indexTestUnit('''
+main() {
+// start
+  int v = 5;
+  return v + 1;
+// end
+}
+''');
+    _createRefactoringForStartEndComments();
+    // apply refactoring
+    return _assertSuccessfulRefactoring('''
+main() {
+// start
+  return res();
+// end
+}
+
+int res() {
+  int v = 5;
+  return v + 1;
+}
+''');
+  }
+
+  test_statements_return_single() {
+    indexTestUnit('''
+main() {
+// start
+  return 42;
+// end
+}
+''');
+    _createRefactoringForStartEndComments();
+    // apply refactoring
+    return _assertSuccessfulRefactoring('''
+main() {
+// start
+  return res();
+// end
+}
+
+int res() {
+  return 42;
+}
+''');
+  }
+
+  /**
+   * We have 3 identical statements, but select only 2.
+   * This should not cause problems.
+   */
+  test_statements_twoOfThree() {
+    indexTestUnit('''
+main() {
+// start
+  print(0);
+  print(0);
+// end
+  print(0);
+}
+''');
+    _createRefactoringForStartEndComments();
+    // apply refactoring
+    return _assertSuccessfulRefactoring('''
+main() {
+// start
+  res();
+// end
+  print(0);
+}
+
+void res() {
+  print(0);
+  print(0);
+}
+''');
+  }
+
+  Future _assertConditionsError(String message) {
+    return refactoring.checkAllConditions().then((status) {
+      assertRefactoringStatus(
+          status,
+          RefactoringProblemSeverity.ERROR,
+          expectedMessage: message);
+    });
+  }
+
+  Future _assertConditionsFatal(String message) {
+    return refactoring.checkAllConditions().then((status) {
+      assertRefactoringStatus(
+          status,
+          RefactoringProblemSeverity.FATAL,
+          expectedMessage: message);
+    });
+  }
+
+  /**
+   * Checks that all conditions are OK and the result of applying the [Change]
+   * to [testUnit] is [expectedCode].
+   */
+  Future _assertSuccessfulRefactoring(String expectedCode) {
+    return assertRefactoringConditionsOK().then((_) {
+      refactoring.createGetter = false;
+      return refactoring.createChange().then((SourceChange refactoringChange) {
+        this.refactoringChange = refactoringChange;
+        assertTestChangeResult(expectedCode);
+      });
+    });
+  }
+
+  void _createRefactoring(int offset, int length) {
+    refactoring =
+        new ExtractMethodRefactoringImpl(searchEngine, testUnit, offset, length);
+    refactoring.name = 'res';
+  }
+
+
+//  Future _assertInitialConditions_fatal_selection() {
+//    return refactoring.checkInitialConditions().then((status) {
+//      assertRefactoringStatus(
+//          status,
+//          RefactoringProblemSeverity.FATAL,
+//          expectedMessage: 'Expression must be selected to activate this refactoring.');
+//    });
+//  }
+
+  void _createRefactoringForStartEndComments() {
+    int offset = findEnd('// start') + '\n'.length;
+    int end = findOffset('// end');
+    _createRefactoring(offset, end - offset);
+  }
+
+  void _createRefactoringForStartEndString(String startSearch,
+      String endSearch) {
+    int offset = findOffset(startSearch);
+    int end = findOffset(endSearch);
+    _createRefactoring(offset, end - offset);
+  }
+
+  /**
+   * Creates a new refactoring in [refactoring] for the selection range of the
+   * given [search] pattern.
+   */
+  void _createRefactoringForString(String search) {
+    int offset = findOffset(search);
+    int length = search.length;
+    _createRefactoring(offset, length);
+  }
+
+  void _createRefactoringWithSuffix(String selectionSearch, String suffix) {
+    int offset = findOffset(selectionSearch + suffix);
+    int length = selectionSearch.length;
+    _createRefactoring(offset, length);
+  }
+}