Add a task to the new task model for computing constant values.

pkg/analyzer/test/src/task/dart_test.dart

 // Copyright (c) 2015, 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.src.task.dart_test;
 
 import 'package:analyzer/src/context/cache.dart';
 import 'package:analyzer/src/generated/ast.dart';
+import 'package:analyzer/src/generated/constant.dart';
 import 'package:analyzer/src/generated/element.dart';
 import 'package:analyzer/src/generated/error.dart';
 import 'package:analyzer/src/generated/resolver.dart';
 import 'package:analyzer/src/generated/source.dart';
 import 'package:analyzer/src/task/dart.dart';
 import 'package:analyzer/task/dart.dart';
 import 'package:analyzer/task/general.dart';
 import 'package:analyzer/task/model.dart';
 import 'package:unittest/unittest.dart';
 
 import '../../generated/test_support.dart';
 import '../../reflective_tests.dart';
 import '../context/abstract_context.dart';
 
 main() {
   groupSep = ' | ';
   runReflectiveTests(BuildClassConstructorsTaskTest);
   runReflectiveTests(BuildCompilationUnitElementTaskTest);
   runReflectiveTests(BuildDirectiveElementsTaskTest);
   runReflectiveTests(BuildEnumMemberElementsTaskTest);
   runReflectiveTests(BuildSourceClosuresTaskTest);
   runReflectiveTests(BuildExportNamespaceTaskTest);
   runReflectiveTests(BuildFunctionTypeAliasesTaskTest);
   runReflectiveTests(BuildLibraryConstructorsTaskTest);
   runReflectiveTests(BuildLibraryElementTaskTest);
   runReflectiveTests(BuildPublicNamespaceTaskTest);
   runReflectiveTests(BuildTypeProviderTaskTest);
   runReflectiveTests(ComputeConstantDependenciesTaskTest);
+  runReflectiveTests(ComputeConstantValueTaskTest);
   runReflectiveTests(ContainingLibrariesTaskTest);
   runReflectiveTests(DartErrorsTaskTest);
   runReflectiveTests(GatherUsedImportedElementsTaskTest);
   runReflectiveTests(GatherUsedLocalElementsTaskTest);
   runReflectiveTests(GenerateHintsTaskTest);
   runReflectiveTests(LibraryUnitErrorsTaskTest);
   runReflectiveTests(ParseDartTaskTest);
   runReflectiveTests(ResolveUnitTypeNamesTaskTest);
   runReflectiveTests(ResolveLibraryTypeNamesTaskTest);
   runReflectiveTests(ResolveReferencesTaskTest);
@@ skipping 1129 matching lines @@
         accessor.isGetter && accessor.name == 'x').variable;
     Element y = accessors.firstWhere((PropertyAccessorElement accessor) =>
         accessor.isGetter && accessor.name == 'y').variable;
     // Now compute the dependencies for x, and check that it is the list [y].
     _computeResult(x, CONSTANT_DEPENDENCIES);
     expect(outputs[CONSTANT_DEPENDENCIES], [y]);
   }
 }
 
 @reflectiveTest
+class ComputeConstantValueTaskTest extends _AbstractDartTaskTest {
+  fail_circular_reference() {
+    // TODO(paulberry): get this to work.
+    EvaluationResultImpl evaluationResult = _computeTopLevelVariableConstValue(
+        'x', '''
+const x = y + 1;
+const y = x + 1;
+''');
+    expect(evaluationResult, isNotNull);
+    expect(evaluationResult.value, isNull);
+    expect(evaluationResult.errors, hasLength(1));
+    expect(evaluationResult.errors[0].errorCode,
+        CompileTimeErrorCode.RECURSIVE_COMPILE_TIME_CONSTANT);
+  }
+
+  test_dependency() {
+    EvaluationResultImpl evaluationResult = _computeTopLevelVariableConstValue(
+        'x', '''
+const x = y + 1;
+const y = 1;
+''');
+    expect(evaluationResult, isNotNull);
+    expect(evaluationResult.value, isNotNull);
+    expect(evaluationResult.value.intValue, 2);
+  }
+
+  test_simple_constant() {
+    EvaluationResultImpl evaluationResult = _computeTopLevelVariableConstValue(
+        'x', '''
+const x = 1;
+''');
+    expect(evaluationResult, isNotNull);
+    expect(evaluationResult.value, isNotNull);
+    expect(evaluationResult.value.intValue, 1);
+  }
+
+  EvaluationResultImpl _computeTopLevelVariableConstValue(
+      String variableName, String content) {
+    Source source = newSource('/test.dart', content);
+    // First compute the library element for the source.
+    _computeResult(source, LIBRARY_ELEMENT1);
+    LibraryElement libraryElement = outputs[LIBRARY_ELEMENT1];
+    // Find the element for the given constant.
+    List<PropertyAccessorElement> accessors =
+        libraryElement.definingCompilationUnit.accessors;
+    Element variableElement = accessors
+        .firstWhere((PropertyAccessorElement accessor) {
+      return accessor.isGetter && accessor.name == variableName;
+    }).variable;
+    // Now compute the value of the constant.
+    _computeResult(variableElement, CONSTANT_EVALUATED_ELEMENT);
+    expect(outputs[CONSTANT_EVALUATED_ELEMENT], same(variableElement));
+    EvaluationResultImpl evaluationResult =
+        (variableElement as TopLevelVariableElementImpl).evaluationResult;
+    return evaluationResult;
+  }
+}
+
+@reflectiveTest
 class ContainingLibrariesTaskTest extends _AbstractDartTaskTest {
   test_buildInputs() {
     Map<String, TaskInput> inputs =
         ContainingLibrariesTask.buildInputs(emptySource);
     expect(inputs, isNotNull);
     expect(inputs, isEmpty);
   }
 
   test_constructor() {
     ContainingLibrariesTask task =
@@ skipping 911 matching lines @@
   /**
    * Fill [errorListener] with [result] errors in the current [task].
    */
   void _fillErrorListener(ResultDescriptor<List<AnalysisError>> result) {
     List<AnalysisError> errors = task.outputs[result];
     expect(errors, isNotNull, reason: result.name);
     errorListener = new GatheringErrorListener();
     errorListener.addAll(errors);
   }
 }