Add 'Introduce new local with cast type' quick assist.

pkg/analysis_server/test/services/correction/assist_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.correction.assist;
 
 import 'package:analysis_server/src/protocol.dart';
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/index/index.dart';
 import 'package:analysis_server/src/services/index/local_memory_index.dart';
@@ skipping 886 matching lines @@
   void test_importAddShow_BAD_hasShow() {
     _indexTestUnit('''
 import 'dart:math' show PI;
 main() {
   PI;
 }
 ''');
     assertNoAssistAt('import ', AssistKind.IMPORT_ADD_SHOW);
   }
 
+  void test_importAddShow_BAD_unresolvedUri() {
+    _indexTestUnit('''
+import '/no/such/lib.dart';
+''');
+    assertNoAssistAt('import ', AssistKind.IMPORT_ADD_SHOW);
+  }
+
   void test_importAddShow_BAD_unused() {
     _indexTestUnit('''
 import 'dart:math';
 ''');
     assertNoAssistAt('import ', AssistKind.IMPORT_ADD_SHOW);
   }
-
-  void test_importAddShow_BAD_unresolvedUri() {
-    _indexTestUnit('''
-import '/no/such/lib.dart';
-''');
-    assertNoAssistAt('import ', AssistKind.IMPORT_ADD_SHOW);
-  }
 
   void test_importAddShow_OK_hasUnresolvedIdentifier() {
     _indexTestUnit('''
 import 'dart:math';
 main(x) {
   PI;
   return x.foo();
 }
 ''');
     assertHasAssistAt('import ', AssistKind.IMPORT_ADD_SHOW, '''
@@ skipping 36 matching lines @@
     assertHasAssistAt('art:math', AssistKind.IMPORT_ADD_SHOW, '''
 import 'dart:math' show E, PI, max;
 main() {
   PI;
   E;
   max(1, 2);
 }
 ''');
   }
 
+  void test_introduceLocalCastType_BAD_notBlock() {
+    _indexTestUnit('''
+main(p) {
+  if (p is String)
+    print('not a block');
+}
+''');
+    assertNoAssistAt('if (p', AssistKind.INTRODUCE_LOCAL_CAST_TYPE);
+  }
+
+  void test_introduceLocalCastType_BAD_notIsExpression() {
+    _indexTestUnit('''
+main(p) {
+  if (p == null) {
+  }
+}
+''');
+    assertNoAssistAt('if (p', AssistKind.INTRODUCE_LOCAL_CAST_TYPE);
+  }
+
+  void test_introduceLocalCastType_OK_if() {
+    _indexTestUnit('''
+class MyTypeName {}
+main(p) {
+  if (p is MyTypeName) {
+  }
+  p = null;
+}
+''');
+    String expected = '''
+class MyTypeName {}
+main(p) {
+  if (p is MyTypeName) {
+    MyTypeName myTypeName = p;
+  }
+  p = null;
+}
+''';
+    assertHasAssistAt(
+        'is MyType',
+        AssistKind.INTRODUCE_LOCAL_CAST_TYPE,
+        expected);
+    _assertLinkedGroup(
+        change.linkedEditGroups[0],
+        ['myTypeName = '],
+        expectedSuggestions(
+            LinkedEditSuggestionKind.VARIABLE,
+            ['myTypeName', 'typeName', 'name']));
+    // another good location
+    assertHasAssistAt('if (p', AssistKind.INTRODUCE_LOCAL_CAST_TYPE, expected);
+  }
+
+  void test_introduceLocalCastType_OK_while() {
+    _indexTestUnit('''
+main(p) {
+  while (p is String) {
+  }
+  p = null;
+}
+''');
+    String expected = '''
+main(p) {
+  while (p is String) {
+    String s = p;
+  }
+  p = null;
+}
+''';
+    assertHasAssistAt(
+        'is String',
+        AssistKind.INTRODUCE_LOCAL_CAST_TYPE,
+        expected);
+    assertHasAssistAt(
+        'while (p',
+        AssistKind.INTRODUCE_LOCAL_CAST_TYPE,
+        expected);
+  }
+
   void test_invertIfStatement_blocks() {
     _indexTestUnit('''
 main() {
   if (true) {
     0;
   } else {
     1;
   }
 }
 ''');
@@ skipping 1256 matching lines @@
   void _indexTestUnit(String code) {
     resolveTestUnit(code);
     index.indexUnit(context, testUnit);
   }
 
   void _setStartEndSelection() {
     offset = findOffset('// start\n') + '// start\n'.length;
     length = findOffset('// end') - offset;
   }
 }