vim: fix python test

The previous test doesn't really work. Switch to a new test that
actually attempts to use vim's python capabilities.

Closes #8114.

Signed-off-by: Tomasz Pajor <tomek@polishgeeks.com>

Formula/vim.rb

@@ -119,18 +119,13 @@ class Vim < Formula
   end
 
   test do
-    # Simple test to check if Vim was linked to Python version in $PATH
     if build.with? "python"
-      vim_path = bin/"vim"
-
-      # Get linked framework using otool
-      otool_output = `otool -L #{vim_path} | grep -m 1 Python`.gsub(/\(.*\)/, "").strip.chomp
-
-      # Expand the link and get the python exec path
-      vim_framework_path = Pathname.new(otool_output).realpath.dirname.to_s.chomp
-      system_framework_path = `python-config --exec-prefix`.chomp
-
-      assert_equal system_framework_path, vim_framework_path
+      (testpath/"commands.vim").write <<-EOS.undent
+        :python import vim; vim.current.buffer[0] = 'hello world'
+        :wq
+      EOS
+      system bin/"vim", "-T", "dumb", "-s", "commands.vim", "test.txt"
+      assert_equal (testpath/"test.txt").read, "hello world\n"
     end
   end
 end