Improved error messages for type mismatches.

pkg/unittest/test/matchers_test.dart

Index: pkg/unittest/test/matchers_test.dart
===================================================================
--- pkg/unittest/test/matchers_test.dart	(revision 21707)
+++ pkg/unittest/test/matchers_test.dart	(working copy)
@@ -237,21 +237,26 @@
       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', () {
@@ -502,7 +507,7 @@
       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', () {