bugfixes; update README.md

spec/buffer_spec.lua

@@ -4,10 +4,27 @@ local withbuf = require '__tt_test_tools'
 describe('Buffer', function()
   it('should replace all lines', function()
     withbuf({}, function()
-      local buf = Buffer.new()
+      local buf = Buffer.from_nr()
       buf:all():replace 'bleh'
       local actual_lines = vim.api.nvim_buf_get_lines(buf.buf, 0, -1, false)
       assert.are.same({ 'bleh' }, actual_lines)
     end)
   end)
+
+  it('should replace all but first and last lines', function()
+    withbuf({
+      'one',
+      'two',
+      'three',
+    }, function()
+      local buf = Buffer.from_nr()
+      buf:lines(1, -2):replace 'too'
+      local actual_lines = vim.api.nvim_buf_get_lines(buf.buf, 0, -1, false)
+      assert.are.same({
+        'one',
+        'too',
+        'three',
+      }, actual_lines)
+    end)
+  end)
 end)