Use DDC-friendly test apis

Also removed no-op test
diff --git a/pubspec.yaml b/pubspec.yaml
index 7018a9d..a0b4925 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -11,4 +11,4 @@
   quiver: '^0.24.0'
 dev_dependencies:
   dart_style: '^0.2.0'
-  test: '^0.12.0'
+  test: '^0.12.17'
diff --git a/test/observable_test.dart b/test/observable_test.dart
index af4d9c3..fb07552 100644
--- a/test/observable_test.dart
+++ b/test/observable_test.dart
@@ -23,11 +23,6 @@
     for (var sub in subs) sub.cancel();
   });
 
-  test('handle future result', () {
-    var callback = expectAsync(() {});
-    return new Future(callback);
-  });
-
   test('no observers', () {
     var t = createModel(123);
     expect(t.value, 123);
@@ -48,7 +43,7 @@
     var t = createModel(123);
     int called = 0;
 
-    subs.add(t.changes.listen(expectAsync((records) {
+    subs.add(t.changes.listen(expectAsync1((records) {
       called++;
       expectPropertyChanges(records, 2);
     })));
@@ -62,7 +57,7 @@
     var t = createModel(123);
     int called = 0;
 
-    subs.add(t.changes.listen(expectAsync((records) {
+    subs.add(t.changes.listen(expectAsync1((records) {
       called++;
       expectPropertyChanges(records, 1);
       if (called == 1) {
@@ -81,8 +76,8 @@
       expectPropertyChanges(records, 2);
     }
 
-    subs.add(t.changes.listen(expectAsync(verifyRecords)));
-    subs.add(t.changes.listen(expectAsync(verifyRecords)));
+    subs.add(t.changes.listen(expectAsync1(verifyRecords)));
+    subs.add(t.changes.listen(expectAsync1(verifyRecords)));
 
     t.value = 41;
     t.value = 42;
@@ -112,7 +107,7 @@
   test('cancel listening', () {
     var t = createModel(123);
     var sub;
-    sub = t.changes.listen(expectAsync((records) {
+    sub = t.changes.listen(expectAsync1((records) {
       expectPropertyChanges(records, 1);
       sub.cancel();
       t.value = 777;
@@ -123,12 +118,12 @@
   test('cancel and reobserve', () {
     var t = createModel(123);
     var sub;
-    sub = t.changes.listen(expectAsync((records) {
+    sub = t.changes.listen(expectAsync1((records) {
       expectPropertyChanges(records, 1);
       sub.cancel();
 
       scheduleMicrotask(() {
-        subs.add(t.changes.listen(expectAsync((records) {
+        subs.add(t.changes.listen(expectAsync1((records) {
           expectPropertyChanges(records, 1);
         })));
         t.value = 777;