Implement multitest failure expectations.

pkg/testing/lib/src/chain.dart

Index: pkg/testing/lib/src/chain.dart
diff --git a/pkg/testing/lib/src/chain.dart b/pkg/testing/lib/src/chain.dart
index 4d7063cc2079805f9aa670db1b4c9d05db0f0ceb..1dcd538b4c665fd38a4c4cfb4fee80a561bdb434 100644
--- a/pkg/testing/lib/src/chain.dart
+++ b/pkg/testing/lib/src/chain.dart
@@ -196,7 +196,8 @@ abstract class ChainContext {
           }
           if (description.multitestExpectations != null) {
             if (isError(description.multitestExpectations)) {
-              result = result.toNegativeTestResult();
+              result = toNegativeTestResult(
+                  result, description.multitestExpectations);
             }
           } else if (lastStep == lastStepRun &&
               description.shortName.endsWith("negative_test")) {
@@ -205,7 +206,7 @@ abstract class ChainContext {
             } else if (result.outcome == Expectation.FAIL) {
               result.addLog("Negative test reported an error as expeceted.\n");
             }
-            result = result.toNegativeTestResult();
+            result = toNegativeTestResult(result);
           }
           if (!expectedOutcomes.contains(result.outcome)) {
             result.addLog("$sb");
@@ -316,13 +317,7 @@ class Result<O> {
     logs.add(log);
   }
 
-  Result<O> toNegativeTestResult() {
-    Expectation outcome = this.outcome;
-    if (outcome == Expectation.PASS) {
-      outcome = Expectation.FAIL;
-    } else if (outcome == Expectation.FAIL) {
-      outcome = Expectation.PASS;
-    }
+  Result<O> copyWithOutcome(Expectation outcome) {
     return new Result<O>(output, outcome, error, trace)
         ..logs.addAll(logs);
   }
@@ -339,3 +334,22 @@ Future<Null> runChain(
     return context.run(suite, selectors);
   });
 }
+
+Result toNegativeTestResult(Result result, [Set<String> expectations]) {
+  Expectation outcome = result.outcome;
+  if (outcome == Expectation.PASS) {
+    if (expectations == null) {
+      outcome = Expectation.FAIL;
+    } else if (expectations.contains("compile-time error")) {
+      outcome = Expectation.MISSING_COMPILETIME_ERROR;
+    } else if (expectations.contains("runtime error") ||
+        expectations.contains("dynamic type error")) {
+      outcome = Expectation.MISSING_RUNTIME_ERROR;
+    } else {
+      outcome = Expectation.FAIL;
+    }
+  } else if (outcome == Expectation.FAIL) {
+    outcome = Expectation.PASS;
+  }
+  return result.copyWithOutcome(outcome);
+}