Lua: allow passing an environment to `run_lua_filter`.

The default is now to use a *copy* of the global environment when running a
filter; this ensures better separation when `run_lua_filter` is used multiple
times. A custom environment can be specified via the optional third parameter.

1 files changed, 44 insertions, 0 deletions

diff --git a/pandoc-lua-engine/test/lua/module/pandoc-utils.lua b/pandoc-lua-engine/test/lua/module/pandoc-utils.lua
index a31250bfe..573a5987a 100644
--- a/pandoc-lua-engine/test/lua/module/pandoc-utils.lua
+++ b/pandoc-lua-engine/test/lua/module/pandoc-utils.lua
@@ -1,5 +1,7 @@
 local tasty = require 'tasty'
+local pandoc = require 'pandoc'
 local utils = require 'pandoc.utils'
+local io = require 'io'
 
 local assert = tasty.assert
 local test = tasty.test_case
@@ -127,6 +129,48 @@ return {
     end)
   },
 
+  group 'run_lua_filter' {
+    test('runs a filter', function ()
+      local doc = pandoc.Pandoc("indivisible words")
+      pandoc.system.with_temporary_directory('lua-filter', function (dir)
+        local filter_path = pandoc.path.join{dir, 'test.lua'}
+        local filter = 'function Space() return " " end'
+        local fh = io.open(filter_path, 'wb')
+        fh:write(filter)
+        fh:close()
+        assert.are_equal(
+          utils.run_lua_filter(doc, filter_path),
+          pandoc.Pandoc(
+            pandoc.Plain(pandoc.Inlines{"indivisible", " ", "words"})
+          )
+        )
+      end)
+    end),
+    test("doesn't change the local environment by default", function ()
+      pandoc.system.with_temporary_directory('lua-filter', function (dir)
+        local filter_path = pandoc.path.join{dir, 'test.lua'}
+        local foo
+        local filter = 'foo = 42'
+        local fh = io.open(filter_path, 'wb')
+        fh:write(filter)
+        fh:close()
+        utils.run_lua_filter(pandoc.Pandoc{}, filter_path)
+        assert.is_nil(foo)
+      end)
+    end),
+    test("accepts an environment in which the filter is executed", function ()
+      pandoc.system.with_temporary_directory('lua-filter', function (dir)
+        local filter_path = pandoc.path.join{dir, 'test.lua'}
+        local filter = 'foo = 42'
+        local fh = io.open(filter_path, 'wb')
+        fh:write(filter)
+        fh:close()
+        utils.run_lua_filter(pandoc.Pandoc{}, filter_path, _ENV)
+        assert.are_equal(_ENV.foo, 42)
+      end)
+    end)
+  },
+
   group 'sha1' {
     test('hashing', function ()
       local ref_hash = '0a0a9f2a6772942557ab5355d76af442f8f65e01'