Lua: add a `pandoc.log` module.

3 files changed, 83 insertions, 1 deletions

diff --git a/pandoc-lua-engine/test/Tests/Lua.hs b/pandoc-lua-engine/test/Tests/Lua.hs
index 644f18204..76f3f467d 100644
--- a/pandoc-lua-engine/test/Tests/Lua.hs
+++ b/pandoc-lua-engine/test/Tests/Lua.hs
@@ -24,10 +24,12 @@ import Text.Pandoc.Builder (bulletList, definitionList, displayMath, divWith,
                             linebreak, math, orderedList, para, plain, rawBlock,
                             singleQuoted, space, str, strong,
                             HasMeta (setMeta))
-import Text.Pandoc.Class (runIOorExplode, setUserDataDir)
+import Text.Pandoc.Class ( CommonState (stVerbosity)
+                         , modifyCommonState, runIOorExplode, setUserDataDir)
 import Text.Pandoc.Definition (Attr, Block (BlockQuote, Div, Para), Pandoc,
                                Inline (Emph, Str), pandocTypesVersion)
 import Text.Pandoc.Error (PandocError (PandocLuaError))
+import Text.Pandoc.Logging (Verbosity (ERROR))
 import Text.Pandoc.Lua (Global (..), applyFilter, runLua, setGlobals)
 import Text.Pandoc.Options (def)
 import Text.Pandoc.Version (pandocVersionText)
@@ -238,6 +240,9 @@ assertFilterConversion msg filterPath docIn expectedDoc = do
 
 runLuaTest :: HasCallStack => Lua.LuaE PandocError a -> IO a
 runLuaTest op = runIOorExplode $ do
+  -- Disable printing of warnings on stderr: some tests will generate
+  -- warnings, we don't want to see those messages.
+  modifyCommonState $ \st -> st { stVerbosity = ERROR }
   res <- runLua $ do
     setGlobals [ PANDOC_WRITER_OPTIONS def ]
     op
diff --git a/pandoc-lua-engine/test/Tests/Lua/Module.hs b/pandoc-lua-engine/test/Tests/Lua/Module.hs
index 47100be78..a5a9570bd 100644
--- a/pandoc-lua-engine/test/Tests/Lua/Module.hs
+++ b/pandoc-lua-engine/test/Tests/Lua/Module.hs
@@ -29,6 +29,8 @@ tests =
                   ("lua" </> "module" </> "pandoc-image.lua")
   , testPandocLua "pandoc.json"
                   ("lua" </> "module" </> "pandoc-json.lua")
+  , testPandocLua "pandoc.log"
+                  ("lua" </> "module" </> "pandoc-log.lua")
   , testPandocLua "pandoc.mediabag"
                   ("lua" </> "module" </> "pandoc-mediabag.lua")
   , testPandocLua "pandoc.path"
diff --git a/pandoc-lua-engine/test/lua/module/pandoc-log.lua b/pandoc-lua-engine/test/lua/module/pandoc-log.lua
new file mode 100644
index 000000000..923f03cd9
--- /dev/null
+++ b/pandoc-lua-engine/test/lua/module/pandoc-log.lua
@@ -0,0 +1,75 @@
+--
+-- Tests for the pandoc.log module
+--
+-- =========================================
+-- PLEASE BE CAREFUL WHEN UPDATING THE TESTS
+-- =========================================
+--
+-- Some tests here are very, very fragile, as their correctness depends on the
+-- correct line number in this file.
+local log = require 'pandoc.log'
+local json = require 'pandoc.json'
+local tasty = require 'tasty'
+
+local group = tasty.test_group
+local test = tasty.test_case
+local assert = tasty.assert
+
+return {
+  group 'info' {
+    test('is a function', function ()
+           assert.are_equal(type(log.info), 'function')
+    end),
+    test('reports a warning', function ()
+      log.info('info test')
+      local msg = json.decode(json.encode(PANDOC_STATE.log[1]))
+      assert.are_equal(msg.message, 'info test')
+      assert.are_equal(msg.type, 'ScriptingInfo')
+    end),
+    test('info includes the correct number', function ()
+      log.info('line number test')
+      local msg = json.decode(json.encode(PANDOC_STATE.log[1]))
+      -- THIS NEEDS UPDATING if lines above are shifted.
+      assert.are_equal(msg.line, 30)
+    end),
+  },
+
+  group 'warn' {
+    test('is a function', function ()
+      assert.are_equal(type(log.warn), 'function')
+    end),
+    test('reports a warning', function ()
+      log.warn('testing')
+      local msg = json.decode(json.encode(PANDOC_STATE.log[1]))
+      assert.are_equal(msg.message, 'testing')
+      assert.are_equal(msg.type, 'ScriptingWarning')
+    end),
+  },
+
+  group 'silence' {
+    test('prevents info from being logged', function ()
+      local current_messages = PANDOC_STATE.log
+      log.silence(log.info, 'Just so you know')
+      assert.are_same(#current_messages, #PANDOC_STATE.log)
+      for i = 1, #current_messages do
+        assert.are_equal(
+          json.encode(current_messages[i]),
+          json.encode(PANDOC_STATE.log[i])
+        )
+      end
+    end),
+    test('returns the messages raised by the called function', function ()
+           local msgs = log.silence(log.info, 'Just so you know')
+           local msg = json.decode(json.encode(msgs[1]))
+           assert.are_equal(msg.message, 'Just so you know')
+    end),
+    test('returns function application results as additional return values',
+         function ()
+           local l, x, y = log.silence(function (a, b) return b, a + b end, 5, 8)
+           assert.are_same(l, {})
+           assert.are_equal(x, 8)
+        assert.are_equal(y, 13)
+      end
+    )
+  }
+}