patch 7.4.1703
Problem:    Can't assert for not equal and not matching.
Solution:   Add assert_notmatch() and assert_notequal().
diff --git a/src/testdir/test_assert.vim b/src/testdir/test_assert.vim
index bc025b4..d7fb638 100644
--- a/src/testdir/test_assert.vim
+++ b/src/testdir/test_assert.vim
@@ -18,6 +18,22 @@
   call assert_equal(4, n)
   let l = [1, 2, 3]
   call assert_equal([1, 2, 3], l)
+
+  let s = 'foo'
+  call assert_equal('bar', s)
+  call assert_match("Expected 'bar' but got 'foo'", v:errors[0])
+  call remove(v:errors, 0)
+endfunc
+
+func Test_assert_notequal()
+  let n = 4
+  call assert_notequal('foo', n)
+  let s = 'foo'
+  call assert_notequal([1, 2, 3], s)
+
+  call assert_notequal('foo', s)
+  call assert_match("Expected 'foo' differs from 'foo'", v:errors[0])
+  call remove(v:errors, 0)
 endfunc
 
 func Test_assert_exception()
@@ -74,6 +90,15 @@
   call remove(v:errors, 0)
 endfunc
 
+func Test_notmatch()
+  call assert_notmatch('foo', 'bar')
+  call assert_notmatch('^foobar$', 'foobars')
+
+  call assert_notmatch('foo', 'foobar')
+  call assert_match("Pattern 'foo' does match 'foobar'", v:errors[0])
+  call remove(v:errors, 0)
+endfunc
+
 func Test_assert_fail_fails()
   call assert_fails('xxx', {})
   call assert_match("Expected {} but got 'E731:", v:errors[0])