Improved error messages for type mismatches.

pkg/unittest/test/matchers_test.dart

 // Copyright (c) 2012, 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 unittestTests;
 import 'package:unittest/unittest.dart';
 import 'dart:async';
 import 'dart:collection';
 part 'test_utils.dart';
 
@@ skipping 219 matching lines @@
         "Expected: an object with length of <2> "
         "but: was <[0]> with length of <1>.");
 
       b.add(0);
       shouldFail(b, hasLength(1),
         "Expected: an object with length of <1> "
         "but: was <[0, 0]> with length of <2>.");
       shouldPass(b, hasLength(2));
     });
 
-    test('type mismatch', () {
-      var a = new DateTime.utc(2000);
-      var b = a.toString();
-      // We should get something like:
-      //    Expected: '2000-01-01 00:00:00.000Z'
-      //    but: expected String:'2000-01-01 00:00:00.000Z'
-      //    but was DateTime:<2000-01-01 00:00:00.000Z>.
-      // However, if minification is applied, then the type names
-      // will be shortened to two letters. The key thing is that
-      // there will be a "but: expected" part in the middle;
-      // this only happens with type mismatches or mismatches
-      // inside container types.
-      shouldFail(a, equals(b),
-          matches(new RegExp("^Expected.*but: expected .*but was.*\$")));
+    test('scalar type mismatch', () {
+      shouldFail('error', equals(5.0),
+          matches("^Expected: <5\.0>"
+                  "     but: was .*:'error' \\(not type .*\\)\.\$"));

[Siggi Cherem (dart-lang), 2013/04/19 17:18:24]

now that is shorter, can we spell it out here?

" but: was String:'error' ..."

(same below)

+    });
+
+    test('nested type mismatch', () {
+      shouldFail(['error'], equals([5.0]),
+          matches(r"^Expected: <\[5\.0\]>"
+                  "     but: expected double:<5\.0> "
+                  "but was .*:'error' mismatch at position 0\.\$"));
+    });
+
+    test('doubly-nested type mismatch', () {
+      shouldFail([['error']], equals([[5.0]]),
+          matches(r"^Expected: <\[\[5\.0\]\]>"
+                  "     but: expected double:<5\.0> "
+                  "but was .*:'error' mismatch at position 0 "
+                  "mismatch at position 0\.\$"));
     });
   });
 
   group('Numeric Matchers', () {
 
     test('greaterThan', () {
       shouldPass(10, greaterThan(9));
       shouldFail(9, greaterThan(10),
         "Expected: a value greater than <10> but: was <9>.");
     });
@@ skipping 231 matching lines @@
       shouldFail(e, someElement(2),
           "Expected: some element <2> but: was <[1, 1, 1]>.");
     });
 
     test('orderedEquals', () {
       shouldPass([null], orderedEquals([null]));
       var d = [1, 2];
       shouldPass(d, orderedEquals([1, 2]));
       shouldFail(d, orderedEquals([2, 1]),
           "Expected: equals <[2, 1]> ordered "
-          "but: was <1> mismatch at position 0.");
+          "but: expected <2> but was <1> mismatch at position 0.");
     });
 
     test('unorderedEquals', () {
       var d = [1, 2];
       shouldPass(d, unorderedEquals([2, 1]));
       shouldFail(d, unorderedEquals([1]),
           "Expected: equals <[1]> unordered "
           "but: has too many elements (2 > 1).");
       shouldFail(d, unorderedEquals([3, 2, 1]),
           "Expected: equals <[3, 2, 1]> unordered "
@@ skipping 187 matching lines @@
       var w = new Widget();
       w.price = 10;
       shouldPass(w, new HasPrice(greaterThan(0)));
       shouldFail(w, new HasPrice(greaterThan(10)),
           'Expected: Widget with a price that is a value greater than <10> '
           'but: price was <10>.');
     });
   });
 }