diff --git a/src/testdir/test_assert.vim b/src/testdir/test_assert.vim
index 01e7718..5d4abaa 100644
--- a/src/testdir/test_assert.vim
+++ b/src/testdir/test_assert.vim
@@ -276,6 +276,21 @@
   call assert_match("E1222: String or List required for argument 2", exp)
 
   try
+    call assert_equal(0, assert_fails('xxx', [#{one: 1}]))
+  catch
+    let exp = v:exception
+  endtry
+  call assert_match("E731: Using a Dictionary as a String", exp)
+
+  let exp = ''
+  try
+    call assert_equal(0, assert_fails('xxx', ['E492', #{one: 1}]))
+  catch
+    let exp = v:exception
+  endtry
+  call assert_match("E731: Using a Dictionary as a String", exp)
+
+  try
     call assert_equal(1, assert_fails('xxx', 'E492', '', 'burp'))
   catch
     let exp = v:exception
@@ -289,8 +304,8 @@
   endtry
   call assert_match("E1174: String required for argument 5", exp)
 
-  call assert_equal(1, assert_fails('c0', ['', '\1']))
-  call assert_match("Expected '\\\\\\\\1' but got 'E939: Positive count required: c0': c0", v:errors[0])
+  call assert_equal(1, assert_fails('c0', ['', '\(.\)\1']))
+  call assert_match("Expected '\\\\\\\\(.\\\\\\\\)\\\\\\\\1' but got 'E939: Positive count required: c0': c0", v:errors[0])
   call remove(v:errors, 0)
 endfunc