Refactor of PolymerExpressions. Adds "as" expressions.

pkg/polymer_expressions/test/syntax_test.dart

 // Copyright (c) 2013, 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 'dart:async';
 import 'dart:html';
 
 import 'package:logging/logging.dart';
 import 'package:observe/observe.dart';
 import 'package:polymer_expressions/polymer_expressions.dart';
+import 'package:polymer_expressions/eval.dart';
 import 'package:template_binding/template_binding.dart';
-import 'package:unittest/html_config.dart';
+import 'package:unittest/html_enhanced_config.dart';
 import 'package:unittest/unittest.dart';
 
 main() {
-  useHtmlConfiguration();
+  useHtmlEnhancedConfiguration();
 
   group('PolymerExpressions', () {
-    var testDiv;
+    DivElement testDiv;
+    int _scope_id;
 
     setUp(() {
       document.body.append(testDiv = new DivElement());
+      _scope_id = 0;
     });
 
     tearDown(() {
-      testDiv.firstChild.remove();
+      testDiv.children.clear();
       testDiv = null;
     });
 
-    test('should make two-way bindings to inputs', () {
-      testDiv.nodes.add(new Element.html('''
-          <template id="test" bind>
-            <input id="input" value="{{ firstName }}">
-          </template>'''));
-      var person = new Person('John', 'Messerly', ['A', 'B', 'C']);
-      templateBind(query('#test'))
-          ..bindingDelegate = new PolymerExpressions()
-          ..model = person;
-      return new Future.delayed(new Duration()).then((_) {
-        InputElement input = query('#input');
-        expect(input.value, 'John');
-        input.focus();
-        input.value = 'Justin';
-        input.blur();
-        var event = new Event('change');
-        // TODO(justin): figure out how to trigger keyboard events to test
-        // two-way bindings
-      });
-    });
-
-    test('should handle null collections in "in" expressions', () {
-      testDiv.nodes.add(new Element.html('''
-          <template id="test" bind>
-            <template repeat="{{ item in items }}">
-              {{ item }}
-            </template>
-          </template>'''));
-      templateBind(query('#test')).bindingDelegate =
-          new PolymerExpressions(globals: {'items': null});
-      // the template should be the only node
-      expect(testDiv.nodes.length, 1);
-      expect(testDiv.nodes[0].id, 'test');
-    });
-
-    test('should silently handle bad variable names', () {
-      var logger = new Logger('polymer_expressions');
-      var logFuture = logger.onRecord.toList();
-      testDiv.nodes.add(new Element.html('''
-          <template id="test" bind>{{ foo }}</template>'''));
-      templateBind(query('#test'))
-          ..bindingDelegate = new PolymerExpressions()
-          ..model = [];
-      return new Future(() {
-        logger.clearListeners();
-        return logFuture.then((records) {
-          expect(records.length, 1);
-          expect(records.first.message,
-              contains('Error evaluating expression'));
-          expect(records.first.message, contains('foo'));
+    Scope testScopeFactory({model, Map<String, Object> variables,
+        Scope parent}) {
+      var testVariables = variables == null ? {} : new Map.from(variables);
+      testVariables['_scope_id'] = _scope_id++;
+      var scope = new Scope(model: model, variables: testVariables,
+          parent: parent);
+      return scope;
+    }
+
+    Future<Element> setUpTest(String html, {model, Map globals}) {
+      var tag = new Element.html(html);
+      templateBind(tag)
+        ..bindingDelegate = new PolymerExpressions(globals: globals,
+            scopeFactory: testScopeFactory)
+        ..model = model;
+      testDiv.children.clear();
+      testDiv.append(tag);
+      return waitForChange(testDiv);
+    }
+
+    group('scope creation', () {
+      // These tests are sensitive to some internals of the implementation that
+      // might not be visible to applications, but are useful for verifying that
+      // that we're not creating too many Scopes.
+
+      // The reason that we create two Scopes in the cases with one binding is
+      // that <template bind> has one scope for the context to evaluate the bind
+      // binding in, and another scope for the bindings inside the template.
+
+      // We could try to optimize the outer scope away in cases where the
+      // expression is empty, but there are a lot of special cases in the
+      // syntax code already.
+      test('should create two scopes for a single binding', () =>
+        setUpTest('''
+            <template id="test" bind>
+              <div>{{ _scope_id }}</div>

[Siggi Cherem (dart-lang), 2014/03/19 18:37:27]

FYI - just ran this test locally in dart2js, seems to fail because it tries to
lookup the symbol via mirrors and throws an error thinking that _scope_id is a
private property.

Renaming the variable _scope_id to scopeIdCounter fixes the issue.

[justinfagnani, 2014/04/24 00:26:13]

This has been fixed in template binding, and I no longer expose the scope_id
anyway.

+            </template>''',
+            model: new Model('a'))
+        .then((_) {
+          expect(testDiv.children.length, 2);
+          expect(testDiv.children[1].text, '1');
+        }));
+
+      test('should create a single scope for two bindings', () =>
+        setUpTest('''
+            <template id="test" bind>
+              <div>{{ _scope_id }}</div>
+              <div>{{ _scope_id }}</div>
+            </template>''',
+            model: new Model('a'))
+        .then((_) {
+          expect(testDiv.children.length, 3);
+          expect(testDiv.children[1].text, '1');
+          expect(testDiv.children[2].text, '1');
+        }));
+
+      test('should create a new scope for a bind/as binding', () {
+        return setUpTest('''
+            <template id="test" bind>
+              <div>{{ _scope_id }}</div>
+              <template bind="{{ data as a }}" id="inner">
+                <div>{{ _scope_id }}</div>
+                <div>{{ a }}</div>
+                <div>{{ data }}</div>
+              </template>
+            </template>''',
+            model: new Model('foo'))
+        .then((_) {
+          expect(testDiv.children.length, 6);
+          expect(testDiv.children[1].text, '1');
+          expect(testDiv.children[3].text, '2');
+          expect(testDiv.children[4].text, 'foo');
+          expect(testDiv.children[5].text, 'foo');
         });
       });
-    });
+
+      test('should create scopes for a repeat/in binding', () {
+        return setUpTest('''
+            <template id="test" bind>
+              <div>{{ _scope_id }}</div>
+              <template repeat="{{ i in items }}" id="inner">
+                <div>{{ _scope_id }}</div>
+                <div>{{ i }}</div>
+                <div>{{ data }}</div>
+              </template>
+            </template>''',
+            model: new Model('foo'), globals: {'items': ['a', 'b', 'c']})
+        .then((_) {
+          expect(testDiv.children.length, 12);
+          expect(testDiv.children[1].text, '1');
+          expect(testDiv.children[3].text, '2');
+          expect(testDiv.children[4].text, 'a');
+          expect(testDiv.children[5].text, 'foo');
+          expect(testDiv.children[6].text, '3');
+          expect(testDiv.children[7].text, 'b');
+          expect(testDiv.children[8].text, 'foo');
+          expect(testDiv.children[9].text, '4');
+          expect(testDiv.children[10].text, 'c');
+          expect(testDiv.children[11].text, 'foo');
+        });
+      });
+
+
+    });
+
+    group('with template bind', () {
+
+      test('should show a simple binding on the model', () =>
+        setUpTest('''
+            <template id="test" bind>
+              <div>{{ data }}</div>
+            </template>''',
+            model: new Model('a'))
+        .then((_) {
+          expect(testDiv.children.length, 2);
+          expect(testDiv.children[1].text, 'a');
+        }));
+
+      test('should handle an empty binding on the model', () =>
+        setUpTest('''
+            <template id="test" bind>
+              <div>{{ }}</div>
+            </template>''',
+            model: 'a')
+        .then((_) {
+          expect(testDiv.children.length, 2);
+          expect(testDiv.children[1].text, 'a');
+        }));
+
+      test('should show a simple binding to a global', () =>
+        setUpTest('''
+            <template id="test" bind>
+              <div>{{ a }}</div>
+            </template>''',
+            globals: {'a': '123'})
+        .then((_) {
+          expect(testDiv.children.length, 2);
+          expect(testDiv.children[1].text, '123');
+        }));
+
+      test('should show an expression binding', () =>
+        setUpTest('''
+            <template id="test" bind>
+              <div>{{ data + 'b' }}</div>
+            </template>''',
+            model: new Model('a'))
+        .then((_) {
+          expect(testDiv.children.length, 2);
+          expect(testDiv.children[1].text, 'ab');
+        }));
+
+      test('should handle an expression in the bind attribute', () =>
+        setUpTest('''
+            <template id="test" bind="{{ data }}">
+              <div>{{ this }}</div>
+            </template>''',
+            model: new Model('a'))
+        .then((_) {
+          expect(testDiv.children.length, 2);
+          expect(testDiv.children[1].text, 'a');
+        }));
+
+      test('should handle a nested template with an expression in the bind '
+          'attribute', () =>
+        setUpTest('''
+            <template id="test" bind>
+              <template id="inner" bind="{{ data }}">
+                <div>{{ this }}</div>
+              </template>
+            </template>''',
+            model: new Model('a'))
+        .then((_) {
+          expect(testDiv.children.length, 3);
+          expect(testDiv.children[2].text, 'a');
+        }));
+
+
+      test('should handle an "as" expression in the bind attribute', () =>
+        setUpTest('''
+            <template id="test" bind="{{ data as a }}">
+              <div>{{ data }}b</div>
+              <div>{{ a }}c</div>
+            </template>''',
+            model: new Model('a'))
+        .then((_) {
+          expect(testDiv.children.length, 3);
+          expect(testDiv.children[1].text, 'ab');
+          expect(testDiv.children[2].text, 'ac');
+        }));
+
+      /**
+       * This test fails in dart2js because we appear to be tickling a bug in
+       * mirrors via _TemplateIterator.
+       */
+      test('should not resolve names in the outer template from within a nested '
+          'template with a bind binding', () =>
+          setUpTest('''
+              <template id="test" bind>
+                <div>{{ data }}</div>
+                <div>{{ b }}</div>
+                <template id="inner" bind="{{ b }}">
+                  <div>{{ data }}</div>
+                  <div>{{ b }}</div>
+                  <div>{{ this }}</div>
+                </template>
+              </template>''',
+              model: new Model('foo'), globals: {'b': 'bbb'})
+          .then((_) {
+            expect(testDiv.children.map((c) => c.text),
+                ['', 'foo', 'bbb', '', '', 'bbb', 'bbb']);
+        }));
+
+      test('should shadow names in the outer template from within a nested '
+          'template', () =>
+          setUpTest('''
+            <template id="test" bind>
+              <div>{{ a }}</div>
+              <div>{{ b }}</div>
+              <template bind="{{ b as a }}">
+                <div>{{ a }}</div>
+                <div>{{ b }}</div>
+              </template>
+            </template>''',
+            globals: {'a': 'aaa', 'b': 'bbb'})
+        .then((_) {
+          expect(testDiv.children.map((c) => c.text),
+              ['', 'aaa', 'bbb', '', 'bbb', 'bbb']);
+        }));
+
+    });
+
+    group('with template repeat', () {
+
+      test('should handle "in" expressions', () =>
+        setUpTest('''
+            <template id="test" bind>
+              <div>{{ data }}</div>
+              <template repeat="{{ item in items }}">
+                <div>{{ item }}{{ data }}</div>
+              </template>
+            </template>''',
+            globals: {'items': [1, 2, 3]},
+            model: new Model('a'))
+        .then((_) {
+          // expect 6 children: two templates, a div and three instances
+          expect(testDiv.children.map((c) => c.text),
+              ['', 'a', '', '1a', '2a', '3a']);
+        }));
+
+    });
+
+    group('with template if', () {
+
+      Future doTest(value, bool shouldRender) =>
+        setUpTest('''
+            <template id="test" bind>
+              <div>{{ data }}</div>
+              <template if="{{ show }}">
+                <div>{{ data }}</div>
+              </template>
+            </template>''',
+            globals: {'show': value},
+            model: new Model('a'))
+        .then((_) {
+          if (shouldRender) {
+            expect(testDiv.children.length, 4);
+            expect(testDiv.children[1].text, 'a');
+            expect(testDiv.children[3].text, 'a');
+          } else {
+            expect(testDiv.children.length, 3);
+            expect(testDiv.children[1].text, 'a');
+          }
+        });
+
+      test('should render for a true expression',
+          () => doTest(true, true));
+
+      test('should treat a non-null expression as truthy',
+          () => doTest('a', true));
+
+      test('should treat an empty list as truthy',
+          () => doTest([], true));
+
+      test('should handle a false expression',
+          () => doTest(false, false));
+
+      test('should treat null as falsey',
+          () => doTest(null, false));
+    });
+
+    group('error handling', () {
+
+      test('should handle and log bad variable names', () {
+        var logger = new Logger('polymer_expressions');
+        var logFuture = logger.onRecord.toList();
+        return setUpTest('''
+            <template id="test" bind>
+              <span>A</span>
+              <span>{{ foo }}</span>
+              <span>B</span>
+            </template>''')
+        .then((_) {
+          expect(testDiv.children.length, 4);
+          expect(testDiv.children.skip(1).map((c) => c.text), ['A', '', 'B']);
+          logger.clearListeners();
+          return logFuture.then((records) {
+            expect(records.length, 1);
+            expect(records.first.message,
+                contains('Error evaluating expression'));
+            expect(records.first.message, contains('foo'));
+          });
+        });
+      });
+
+      test('should handle null collections in "in" expressions', () =>
+        setUpTest('''
+            <template id="test" bind>
+              <template repeat="{{ item in items }}">
+                {{ item }}
+              </template>
+            </template>''',
+            globals: {'items': null})
+        .then((_) {
+          expect(testDiv.children.length, 2);
+          expect(testDiv.children[0].id, 'test');
+        }));
+
+    });
+
+    group('regression tests', () {
+
+      test('should bind to literals', () =>
+        setUpTest('''
+            <template id="test" bind>
+              <div>{{ 123 }}</div>
+              <div>{{ 123.456 }}</div>
+              <div>{{ "abc" }}</div>
+              <div>{{ true }}</div>
+              <div>{{ null }}</div>
+            </template>''',
+            globals: {'items': null})
+        .then((_) {
+          expect(testDiv.children.length, 6);
+          expect(testDiv.children[1].text, '123');
+          expect(testDiv.children[2].text, '123.456');
+          expect(testDiv.children[3].text, 'abc');
+          expect(testDiv.children[4].text, 'true');
+          expect(testDiv.children[5].text, '');
+        }));
+
+      });
+
   });
 }
 
+Future<Element> waitForChange(Element e) {
+  var completer = new Completer<Element>();
+  new MutationObserver((mutations, observer) {
+    observer.disconnect();
+    completer.complete(e);
+  }).observe(e, childList: true);
+  return completer.future.timeout(new Duration(seconds: 1));
+}
+
 @reflectable
-class Person extends ChangeNotifier {
-  String _firstName;
-  String _lastName;
-  List<String> _items;
-
-  Person(this._firstName, this._lastName, this._items);
-
-  String get firstName => _firstName;
-
-  void set firstName(String value) {
-    _firstName = notifyPropertyChange(#firstName, _firstName, value);
+class Model extends ChangeNotifier {
+  String _data;
+
+  Model(this._data);
+
+  String get data => _data;
+
+  void set data(String value) {
+    _data = notifyPropertyChange(#data, _data, value);
   }
 
-  String get lastName => _lastName;
-
-  void set lastName(String value) {
-    _lastName = notifyPropertyChange(#lastName, _lastName, value);
-  }
-
-  String getFullName() => '$_firstName $_lastName';
-
-  List<String> get items => _items;
-
-  void set items(List<String> value) {
-    _items = notifyPropertyChange(#items, _items, value);
-  }
-
-  String toString() => "Person(firstName: $_firstName, lastName: $_lastName)";
+  String toString() => "Model(data: $_data)";
 }