Allow "null" as a synonym for [] or {} in the analysis server API.

pkg/analysis_server/test/protocol_test.dart

Index: pkg/analysis_server/test/protocol_test.dart
diff --git a/pkg/analysis_server/test/protocol_test.dart b/pkg/analysis_server/test/protocol_test.dart
index 36bf1a2df5d2757cb7a9bbde8150b82379914c96..9013e9129995c2bfeea3edf66580238f0506f81f 100644
--- a/pkg/analysis_server/test/protocol_test.dart
+++ b/pkg/analysis_server/test/protocol_test.dart
@@ -75,6 +75,14 @@ class RequestTest {
   }
 
   @runTest
+  static void getParameter_null() {
+    String name = 'name';
+    Request request = new Request('0', '');
+    request.setParameter(name, null);
+    expect(request.getParameter(name, 'default').datum, equals(null));
+  }
+
+  @runTest
   static void getParameter_undefined() {
     String name = 'name';
     String defaultValue = 'default value';
@@ -92,6 +100,14 @@ class RequestTest {
   }
 
   @runTest
+  static void getRequiredParameter_null() {
+    String name = 'name';
+    Request request = new Request('0', '');
+    request.setParameter(name, null);
+    expect(request.getRequiredParameter(name).datum, equals(null));
+  }
+
+  @runTest
   static void getRequiredParameter_undefined() {
     String name = 'name';
     Request request = new Request('0', '');
@@ -291,6 +307,12 @@ class RequestDatumTest {
   }
 
   @runTest
+  static void indexOperator_null() {
+    setUp();
+    expect(() => makeDatum(null)['foo'], _throwsInvalidParameter);
+  }
+
+  @runTest
   static void indexOperator_missingKey() {
     setUp();
     expect(() => makeDatum({
@@ -321,6 +343,12 @@ class RequestDatumTest {
   }
 
   @runTest
+  static void hasKey_null() {
+    setUp();
+    expect(makeDatum(null).hasKey('foo'), isFalse);
+  }
+
+  @runTest
   static void forEachMap_nonMap() {
     setUp();
     expect(() => makeDatum(1).forEachMap((key, value) {
@@ -337,6 +365,14 @@ class RequestDatumTest {
   }
 
   @runTest
+  static void forEachMap_null() {
+    setUp();
+    makeDatum(null).forEachMap((key, value) {
+      fail('Empty map should not be iterated');
+    });
+  }
+
+  @runTest
   static void forEachMap_oneElementMap() {
     setUp();
     int callCount = 0;
@@ -389,12 +425,27 @@ class RequestDatumTest {
   }
 
   @runTest
+  static void isList() {
+    setUp();
+    expect(makeDatum(3).isList, isFalse);
+    expect(makeDatum(null).isList, isTrue);
+    expect(makeDatum([]).isList, isTrue);
+    expect(makeDatum(['foo', 'bar']).isList, isTrue);
+  }
+
+  @runTest
   static void asList_nonList() {
     setUp();
     expect(() => makeDatum(3).asList((datum) => null), _throwsInvalidParameter);
   }
 
   @runTest
+  static void asList_null() {
+    setUp();
+    expect(makeDatum(null).asList((datum) => datum.asString()), equals([]));
+  }
+
+  @runTest
   static void asList_emptyList() {
     setUp();
     expect(makeDatum([]).asList((datum) => datum.asString()), equals([]));
@@ -414,15 +465,66 @@ class RequestDatumTest {
   }
 
   @runTest
+  static void isStringList() {
+    setUp();
+    expect(makeDatum(['foo', 'bar']).isStringList, isTrue);
+    expect(makeDatum([]).isStringList, isTrue);
+    expect(makeDatum(null).isStringList, isTrue);
+    expect(makeDatum(['foo', 1]).isStringList, isFalse);
+    expect(makeDatum({}).isStringList, isFalse);
+  }
+
+  @runTest
   static void asStringList() {
     setUp();
     expect(makeDatum(['foo', 'bar']).asStringList(), equals(['foo', 'bar']));
     expect(makeDatum([]).asStringList(), equals([]));
+    expect(makeDatum(null).asStringList(), equals([]));
     expect(() => makeDatum(['foo', 1]).asStringList(), _throwsInvalidParameter);
     expect(() => makeDatum({}).asStringList(), _throwsInvalidParameter);
   }
 
   @runTest
+  static void isMap() {
+    setUp();
+    expect(makeDatum({
+      'key1': 'value1',
+      'key2': 'value2'
+    }).isMap, isTrue);
+    expect(makeDatum({}).isMap, isTrue);
+    expect(makeDatum(null).isMap, isTrue);
+    expect(makeDatum({
+      'key1': 'value1',
+      'key2': 2
+    }).isMap, isTrue);
+    expect(makeDatum({
+      'key1': 1,
+      'key2': 2
+    }).isMap, isTrue);
+    expect(makeDatum([]).isMap, isFalse);
+  }
+
+  @runTest
+  static void isStringMap() {
+    setUp();
+    expect(makeDatum({
+      'key1': 'value1',
+      'key2': 'value2'
+    }).isStringMap, isTrue);
+    expect(makeDatum({}).isStringMap, isTrue);
+    expect(makeDatum(null).isStringMap, isTrue);
+    expect(makeDatum({
+      'key1': 'value1',
+      'key2': 2
+    }).isStringMap, isFalse);
+    expect(makeDatum({
+      'key1': 1,
+      'key2': 2
+    }).isStringMap, isFalse);
+    expect(makeDatum([]).isMap, isFalse);
+  }
+
+  @runTest
   static void asStringMap() {
     setUp();
     expect(makeDatum({
@@ -445,6 +547,26 @@ class RequestDatumTest {
   }
 
   @runTest
+  static void isStringListMap() {
+    setUp();
+    expect(makeDatum({
+      'key1': ['value11', 'value12'],
+      'key2': ['value21', 'value22']
+    }).isStringListMap, isTrue);
+    expect(makeDatum({
+      'key1': 10,
+      'key2': 20
+    }).isStringListMap, isFalse);
+    expect(makeDatum({
+      'key1': [11, 12],
+      'key2': [21, 22]
+    }).isStringListMap, isFalse);
+    expect(makeDatum({}).isStringListMap, isTrue);
+    expect(makeDatum(null).isStringListMap, isTrue);
+    expect(makeDatum(3).isStringListMap, isFalse);
+  }
+
+  @runTest
   static void asStringListMap() {
     setUp();
     {
@@ -468,6 +590,9 @@ class RequestDatumTest {
       };
       expect(() => makeDatum(map).asStringListMap(), _throwsInvalidParameter);
     }
+    expect(makeDatum({}).asStringListMap(), equals({}));
+    expect(makeDatum(null).asStringListMap(), equals({}));
+    expect(() => makeDatum(3).asStringListMap(), _throwsInvalidParameter);
   }
 }