Migrate block 44.

pkg/expect/lib/expect.dart

Index: pkg/expect/lib/expect.dart
diff --git a/pkg/expect/lib/expect.dart b/pkg/expect/lib/expect.dart
index c9810b03504f6398de48e8318643a343785c16f6..3acf5327714806aa3898bd8ce9af08d2b0421e22 100644
--- a/pkg/expect/lib/expect.dart
+++ b/pkg/expect/lib/expect.dart
@@ -460,6 +460,10 @@ class Expect {
     Expect.throws(f, (error) => error is ArgumentError, "ArgumentError");
   }
 
+  static void throwsAssertionError(void f()) {
+    Expect.throws(f, (error) => error is AssertionError, "AssertionError");
+  }
+
   static void throwsCastError(void f()) {
     Expect.throws(f, (error) => error is CastError, "CastError");
   }