vim-patch:7.4.1567

Problem:    Crash in assert_fails().
Solution:   Check for NULL. (Dominique Pelle)  Add a test.

1abb502635

test/functional/legacy/assert_spec.lua

@@ -142,4 +142,22 @@ describe('assert function:', function()
       })
     end)
   end)
+
+  -- assert_fails({cmd}, [, {error}])
+  describe('assert_fails', function()
+    it('should change v:errors when error does not match v:errmsg', function()
+      execute([[call assert_fails('xxx', {})]])
+      expected_errors({"Expected {} but got 'E731: using Dictionary as a String'"})
+    end)
+
+    it('should not change v:errors when cmd errors', function()
+      call('assert_fails', 'NonexistentCmd')
+      expected_empty()
+    end)
+
+    it('should change v:errors when cmd succeeds', function()
+      call('assert_fails', 'call empty("")')
+      expected_errors({'command did not fail: call empty("")'})
+    end)
+  end)
 end)